I'm neither sure what the results want (same as designer) - when I woke up lucky to have same dimensions, I had an impression they were to innonsence to adapt in this direction. ( I only wanted to read one more story before going to bed, possibly wonder.. - and it throw me of into.. twisted.. space ? I.. missed what I wanted read.)
> “We needed to understand the Didymos-Dimorphos system before we changed it"
As I understand it, one of the big research questions NASA wanted to answer was whether, if they shot the asteroids, the pieces would just fly off to the side of the screen and then wrap around again to the other side.
Dear colleagues and amateurs, are you sure it was “a Smashing Success»?...
Briefings, emotional interviews, impressive photos, PR-type publications - all this can be important for discussions and conclusions in politics, but not in science. Before the appearance of publications in peer-reviewed journals with detailed data and analysis of the collision consequences for Dimorphos`s orbit, there is nothing to discuss seriously and essentially.
The following must also be taken into account. One million kilograms of ejected fragments is only less than one percent of the total mass of the target. Since the ejection was "fan-shaped", its effect was most likely extremely insignificant, especially with a completely inelastic reaction for impulse transmission to Dimorphos, which is a loose pile of rubble, stones and dust, but not a monolithic rock.
Finally, during photometric and radar observations, nature can played a «cruel joke» with observers who used the mutual eclipses of Didymos and Dimorphos to determine of its orbit changes. The matter is that an asymmetric and optically dense ejection of large asteroid fragments could partially remain in the orbit together with Dimorphos for a long time. With a small value of its first cosmic velocity around of 4 cm/s, this is quite probable and is confirmed by video animation: https://www.youtube.com/watch?v=bfqVqOl9S9w.
In turn, this could lead to optical-geometric distortions in the measurements of the difference between the moments of mutual eclipses due to the displacement of the photometric center with respect to the center of gravity. Using only different types of eclipses, occurring after 6 hours, lead to distortions of around 30 minutes, which could be interpreted as a real change in orbital period.
They consider it a smashing success not only because they achieved the goal they set out to achieve, but because of the "smashing" joke. I don't think they've advertised these deflections as a perfectly reliable system...they're still experiments lmao.
What other organisation is developing and testing planetary defences to such a degree? I'm personally just extremely happy that we're doing _something_ about planet killing objects, now I need only cross my fingers that we don't kill our planet ourselves, through environmental negligence or nuclear war.
I can agree with you, but spending hundreds of millions dollars is too much for a "smashing" joke without achieving the main goal of the mission under discussion...
Please see this video after 50th minute. It shows that Dimorphos has approximately doubled in size. This is an animation compressed 500 times according to the authors, so it seems that this process happened quickly. It can be seen from it that such an increased size remained unchanged, which indicates the "hanging" of the ejection near Dimorphos. The fact that it did not fly far indicates the relatively large size of the ejected fragments.
> Briefings, emotional interviews, impressive photos, PR-type publications - all this can be important for discussions and conclusions in politics, but not in science.
Glad to hear. As crazy as it sounds, I believe that the biggest apology we can give to the planet's inhabitants is using our creations to shield Earth from a potentially catastrophic asteroid that could wipe out vast amounts of life.
Yes, this "repayment" to Earth's biosphere is dulled by the fact that we created weapons decades ago that could wipe out more life than a relatively small asteroid could, but developing and fine tuning these redirection methods is the least we could do to protect this planet's life.
Over 75% of life on earth is behind us (4.2bn years). Humanity’s on a track to save life on earth from the complete extinction event coming in 400M to 800m years. Humans are the first (and very likely only) golden ticket our planet has printed to get life off of this rock. We are heading to the stars, and we will bring life with us.
I love this comment. We're a walking disaster and a literally hot mess, but you're right that we're probably the best chance at preserving life overall.
> We are heading to the stars, and we will bring life with us.
Another way to think about it: we'll be Earth's best, most successful, furthest-flung seeds.
Really I think we should go a step beyond this. Being able to go to some new planet is not guaranteed or that planet may even be inhospitable to us.
What I think is more feasible and more benevolent than preventing a mass extinction is we should slowly expand our orbit so we can survive the brightening sun for at least a while longer. Basically, all we need to do is increase our planets speed over hundreds of millions of years. A certain mass of asteroids with steerable self correcting orbits could push small amounts of speed into our planet that would build up over time.
Even if we don't make it, we at least give life more time to do it's thing.
Modifying our orbit isn't the only thing we could do. We could do starlifting, which is mining our sun, and we can modify the composition of our sun such that it lasts longer and so forth.
Maybe form a polar jet and get the whole solar system (Oort cloud excepted, sorry!) boosted out of the plane of the galaxy.
It is dangerous here! You never know when a supernova or magnetar quake might sterilize the entire solar system. By the time you know it is coming, it is too late to do anything but flee with minimal baggage.
Why would the jet and the radiation emitted by such objects be limited to the plane of the galaxy? AFAIK their axis, and thus the direction of emission are randomly distributed.
Doesn't matter in which direction you are positioned, except for distance. Which would mean the really deep space between galaxies. But then you'd have to watch out for https://en.wikipedia.org/wiki/Seyfert_galaxy ies, too!
Whose jet's could fry us even more easily, because 'out there', we wouldn't be protected by the pressure of solar/stellar/galactic wind, dust clouds, nebula, which could protect us (if we are lucky).
There is no possibility of ever getting close to a different galaxy. The best you can do is get away from the thick part of the galaxy we are in, and its hazards.
The jet I wrote about is one you induce to emit from a pole of the sun, for thrust. I have no idea what this other jet you mention is.
Which made no sense to me, because to escape the other, naturally occurring cones of radiation, emitting from different sources, only distance would matter.
Just rising above the thick part of our galaxy wouldn't be enough IMO. Because it doesn't really matter if you are cought in such a cone, from one side or another, or from above or below.
Because they are oriented randomly, according to the rotational axis of the object in question, which isn't aligned to some 'plane' (AFAIK).
So the only way to be sure would be a much larger distance from the galactic mess, out into real emptiness. Which would open it's own can of worms. Because real emptiness doesn't protect against larger jets, coming from larger objects, like Seyfert-galaxies in active state.
Edit: To further explain my model of thinking about this, while being in the plane of our galaxy, we could be protected by nebulae, dust and gas clouds, depending from where the radiation cone comes. That would be random(luck).
And useless against our next nearest neighbours, if they go
boom for whichever reason, and there aren't any obstacles between that, and us, which could dampen the radiation a little bit. Going up or down the galactic plane, would add just a little distance, but not enough to be safe from all the possible cones of radiation coming out of the plane.
Because from 'in the plane' to above or below it, there are even less obstacles which could dampen the intensity of that. Less 'fog or dust', but still 'in range', thus easier target.
But still somehow in the 'galactic bubble', exerting outwards 'pressure', maybe dampening extragalactic outbursts somewhat.
So using your jet to leave the plane made no sense to me, because it doesn't really protect against the astrophysical jets, and radiation cones emitting from them.
In the plane, there are myriad hazards that, at effectively random times, are right nearby, close enough to sterilize your whole system if they go off then. Most of them -- supernovas and magnetar outbursts -- are not jets. Off-plane, nothing gets close enough to be a hazard except, if you are extra-unlucky, a jet pointed straight at you, which could as well happen were we are now.
Above the plane of the disc, only jet sources near the "top surface" (if there were one) have less dust between them and us than when we were in it. Generally, being farther away is better.
Before you can get far away from your galaxy, you spend a very great deal of time near or in it. Being someplace farther from hazards during that time is better than being nearer to them. The alternative would be to blast toward the rim, staying in the thick part, and spend the whole time getting to the rim at about as much risk as when you started.
OTOH I don't see the danger from anything 'near' to us, going boom, when one of the poles of the rotational axis, no matter the emission mechanism, is not pointed at us.
The omnidirectional stuff is just too weak. If not, we'd be toast anyways, here, or whereever else.
So I'm still unconvinced by your reasoning, but thanks for trying to explain.
You neglect that supernovas and magnetar events are orders of magnitude more common than these focused jet events. When one of the former occurs nearby, there is no possibility of protection.
Objects that threaten it drift in and out of range at random. We have been in range of such an object many times, and just got lucky that they did not go off at those times.
Dust clouds shield you from some kinds of radiation, but make others radically more harmful.
Jet phenomena are commonly long-lived, and avoided by steering away from where they point. You can steer only when you are moving. AGN jets come only from supermassive black holes, and we have only one of those.
The only protection is distance, and distance is achieved by going. Gamma-ray bursts we detect have all been pointed at us, but all from distant galaxies.
But not without asking whether that going would be achievable by any handwavy Sci-Fi means in the necessary time frames. And knowing in advance, before any wavefront is hitting us.
Moving the solar system would take millions of years, but that is a useful timeframe if you are dodging random threats.
For specific threats, you need to put your valuables in cans and boost those to someplace safer, choosing somewhere with resources to replace what you leave behind.
For that to be doable you probably need to solve p-11B fusion, or something better we don't know anything about yet.
If you boost into empty space (and not say the Magelanic Clouds or something similar) you are loosing access to a lot of usable mass. Maybe better to do a lot of backups and stay in the galaxy ?
Magellanic clouds are even more hazardous than where we are.
If you bring the solar system along, you have that; I assume you accelerate slowly enough to bring along the Kuiper Belt. It will take a long time before you need to start thinking about dismantling Jupiter.
If you solve the p-11B fusion problem (maybe you invent a mirror for x-rays?), you don't need the sun anymore, and may pick up and move operations to another solar system that is already moving off-disc at a good clip. You can bring along rotating cans of bio-stuff if you still use it (or anyway keep it as pets).
The new solar system can have a dead-ish star so the planets are frozen and convenient to mine for volatiles.
Pop science has prepared me for this moment. I believe all it takes is for everyone in China to jump at the same time. Maybe they can do that a few times a year for a few thousand years and we're saved.
>Pop science has prepared me for this moment. I believe all it takes is for everyone in China to jump at the same time.
Instead of the orbit perhaps changing the tilt would be better, so everyone in China and their dragons should do a sprint up north. Why should Siberia shiver in the cold while Africa scorch in the sun? the discrimination is obvious.
If we change our orbit to get further away, we'd need to increase our forward velocity, right? By doing that, we'd change the length of the year. Would it be possible to achieve a stable orbit so that the increased speed is offset by extra distance from the increased orbital radius? I'd really hate to have to learn a new calendar system.
Also, would the mass of Earth gradually moving location in the solar system disrupt other objects like say maybe something in the asteroid belt? Would that disruption then start a chain reaction of other objects having their orbits perturbed to the point we've now unleashed a new season of asteroid danger? What about the decreased distance to Jupiter? Big boy will have some strange affects on earth too would he not? Would we lose our moon to the pull from Jupiter? What happens to our tidal systems at that point? Would the loss of the moon be countered by the new tidal pulls from Jupiter?
I'd be a bit disappointed if in a hundred years there were still software developers making exasperated sighs whenever a change were to be introduced in a date standard.
Unless technological civilization collapses it seems a bit odd that we'd still need date standards in a hundred years.
While we need to add energy to Earth to take it further from the sun's gravitational well, this actually results in us slowing down (while increasing the radius of orbit). In order to orbit farther away the year _must_ get longer.
I have no idea what distance would be necessary relative to Mars/Jupiter/asteroid belt.
It is less delta-v expensive if you increase velocity to change orbit rather than a direct push away. Not sure how else you'd propose changing the orbit.
I think the first step is to get a handle on how to sustainably (= for millions of year) live on this planet, given that we’re already slowly approaching its capacity limits in various ways. Then we can see about adjusting the orbit.
Although it would be an interesting experiment to adjust it a little bit to check if it works similar to this asteroid experiment. Maybe when Musk has his fleet of starships but is banned from colonising Mars on environmental grounds, we could repurpose them.
There's 8 billion people on the planet already and something like 80% live in developing countries. There are massive productivity gains to be had as those people improve their education and move into more productive jobs.
How does productivity translate to sustainability? Historically, as countries became more developed and increased productivity, they also increased resource consumption.
Growth has its limits. It is generally sigmoidal (S curve), not exponential. It’s reasonable to assume we’ll hit the inflection point long before the sun becomes a problem.
My point is that we’ll need to find some kind of equilibrium that doesn’t rely on continual growth, because that won’t be sustainable. After we manage that, there’ll be still enough time to worry about the sun. And if we don’t manage that, we’ll be doomed regardless of the sun. (Barring interstellar travel, in which case we may stop caring about the sun anyway.)
Perhaps we should not aim so high as Earth orbit modification. What if we just figure out the Sun's fuel cycle and control that so that it doesn't hurt us.
> It's crazy humans have evolved in less than 0.1% (300k years) of that lower range.
What you mean and what you are suggesting are two different things. Homo sapiens evolved from a similar species less than 300K years ago, not in less than 300K years! It took 62.5M years for humans to evolve from the small mammals that survived the impact that killed the dinosaurs. It was a mere 2.3M years ago when the first humans walked the earth, a species we now call Homo habilis.
You're right, what I meant was that our species, homo sapiens branched off not that long ago, about 300k years. From what we were then to what we are now in an astronomical blink of an eye. And given the exponential growth of development and innovation in the last couple thousand years. And to think we still 400k years to go on earth is just mind boggling.
Very little happened in those 300k years which is why we survived so long. There are a lot more human created existential threats now than 500years ago such as climate change and nuclear weapons.
If shit goes wrong enough just once the next 400M years we have a nuclear war on our hands. Even extremely low probabilities are likely to occur over such long time ranges.
Add to that that bootstrapping a new complex society like we have now is going to be a lot harder without easily accessible fossil fuels and it seems highly unlikely that we will survive in such a way that we could save life on earth from some future crisis.
We are the final stage of a Von-Neumann probe. We are supposed to be identifying potential habitable planets, or what will be by the time our launched packages of biologics arrives.
I don't see any value in humanity leaving the earth (except for fun, which is a good reason). Our children (the robots) are doing a much better job than we are of exploring the solar system or indeed researching saving us by attacking the Didymos-Dimorphos system.
Instead of dragging a chunk of planet around with us everywhere we go, let's leave the travel to the robots that are perfectly adapted to the environment.
You are not thinking in a sufficient timescale. Human civilization is less than 10,000 years old. Barring some type of great filter event, it seems likely that human civilization will saturate the galaxy, or at least the local group, within the 400m years the OP mentioned.
Depends on how much competing interest is out there.
A Petri dish might dream of taking over North America, but the humans might have other plans (for instance, the autoclave across the room).
Maybe they'd reason that North America is entirely lifeless, since nobody has yet tried to communicate the secrets of the Universe to them in a (bacterially) intelligible language.
Honestly the Petri dish has better chances. The bacteria that inhabit one already have the demonstrated ability to persistently survive outside of it.
Fair enough, however the Fermi Paradox and the consequently postulated Great Filter are a thing precisely because the evidence of this competition should be present but is not.
Human civilization is much more than 10,000 years old, but in any case robots can live longer and in more interesting modes (branching, eusocial, etc). They can colonize all sorts of planets unsuitable for us. They should carry our culture, such as it is, forward to the stars and galaxies.
As a living organism I am most interested in increasing the resources and habitat size for my species and decedents. The amount of resources on Earth (or that we could bring to Earth) is a tiny fraction compared to what's available. More resources and more habitats means more people, which means more of everything that makes humanity awesome.
The robots are just a forward scouting tool. Human civilization is essentially 10k years old on galactic time scales, with agriculture being ~12k years old.
I am not the MAILMAN, I am also a living organism and I couldn't care less about those goals. I don't deny that you might have them but they are hardly an automatic consequence of being a human, much less some more general "living organism". They sound pretty high level to me, especially the bit about "species" (whatever that might really mean anyway). Speciation is a human construct.
For all you know you are just running a program designed to transmit a message encoded in some "junk" DNA inherited from some long lost ancestor who was modified by some alien that crashed on our planet billions of years ago who hopes that some terrestrial decendent will eventually arrive at an inhabited planet where the residents will open up the astronaut, read the message, and come rescue your descendants to travel.
> I don't deny that you might have them but they are hardly an automatic consequence of being a human, much less some more general "living organism".
Searching for resources, gathering them, and controlling territory from competitors are basic biological behaviors we see in most (all?) life. On a personal level this behavior might look like visiting a grocery store, storing the food at home, and locking your door.
It seems reasonable that as our technology develops and we exhaust resources on Earth that we will need to increase our reach to resources and territories beyond Earth.
> Searching for resources, gathering them, and controlling territory from competitors are basic biological behaviors we see in most (all?) life.
The vast majority of the mass of life on this planet does not participate in all (and probably in most cases any) of the behavior you describe. Stromatolites, various parasites and symbiotes, most bacteria, etc do little to none of that.
Importing resources from other planets or other extraterrestrial bodies can and would better be done by robots than humans.
Organelles such as flagellum are used for moving to find more resources. A large benefit of cell membranes is to provide a safe place for resources. I'd argue the entire lifecycle of parasites is to find (scout) suitable resource rich environments and to consume them all (gather), often in a way that wrestles territory control from it's host. Here are some articles describing bacteria doing the exact behaviors (search for resource, gather them, and territory control).
EDIT: I wanted to respond to the point "Importing resources from other planets or other extraterrestrial bodies can and would better be done by robots than humans."
I'm sure robotic mining will occur first. However, we have a limit on the amount of resources we can bring to Earth. An estimated 10% of the mass of the astroid belt is water (on Ceres). Saturn's rings contains about half of Earth's glacier's mass as water. There's likely a dozen more large water deposits in our solar system, although we know less about their total mass. Titan, Ganymede, Callisto, twenty more likely candidates. Imagine tripling the amount of water on Earth. Where would sea level be? This is just gathering all "nearby" water, our most basic resource. We also have to consider the demand for metals like gold, platinum and lithium. Our demand for nitrogen to fertilize soil. Our demand for fuel sources such as hydrogen/oxygen, helium-3, or uranium. There's simply more stuff in our solar system than we can possibly fit on Earth or LEO.
I find it interesting that y'all seem to assume that humans will remain biological (for 400m+ years) and will somehow not merge with robots to make the humans vs robots discussion kind of irrelevant.
AGI robots (humanities "daddies") won't care whether humans want to become interplanetary or not. It will just do it itself regardless.
Writing is about 10 Ky old, but clearly organized groups with language, rituals, manufacturing, structures etc long predate that in the fossil record.
Ok language of course technically doesn’t predate writing in the fossil record itself but writing, arithmetic, etc in many languages means that predated writing. Plato reported that Socrates opposed writing. Etc.
I'm still not clear on how you're defining civilization. The typical definition includes large population centers with some central authority, along with trade routes and divided labor. Roughly 3000-4000 BC IIRC.
Writing isn't even as old as civilization by this definition. I'm curious where you're getting this huge 10,000 years ago number from. Maybe you're just rounding up and I'm being a pedant, but I don't think there's much that would be considered civilization many thousands of years prior to Sumer.
That's quite a Spenglarian definition of "civilization". Compare that to, say, Margaret Meade who gave an example of civilization being demonstrated by someone surviving for years post a traumatic injury (broken leg), which required specific non-animal level of cooperation and support of someone who couldn't hunt or gather.
Of course, humans did not go from being unable to care for each other to forming cities overnight. Agriculture and even some amount of trading was happening far before people started wrangling cities within the same control structures. The moment in history when human settlements got large enough to encompass multiple locations and require coordination is a useful concept, and as far as I can tell, modern historians consider that to be around 4000 BC.
That's not to say nothing interesting happened before, or no one was building things or whatever. It just wasn't happening at a scale that required things like a bureaucracy or writing to coordinate things across multiple places.
That would mean there will exist a factor million (or even much higher) more human lives in the future, than there have been so far.
But then, that would mean we are among the "one-in-one-millionth earliest" humans, which is a very improbable position to find yourself in.
We don't actually know what the future holds. But if we have to guess, it is more likely that we are in a typical case. E.g. if you buy a lottery ticket, it is more reasonable to assume that you are not going to win anything, than to assume you are in the one-in-a-million case (holding the ticket that will win).
Applying that logic to our current situation, the reasonable assumption would be that we are close to the peak of human civilization. That's why we find ourselves here, and not in the distant future among a population of quadrillions.
I have never understood this type of argument. Even in my regular life, I am atypical in more than one one-in-a-million way.
I was born in a tiny city, population less than 1000. But following your line of reasoning, that is sufficient argument that the population of the world is less than 1 billion.
It is fine to say "we don't know". Events in which you are in a one-in-a-million situation will be rare, but unless you know the number of events in consideration, there are few conclusions you can draw. There are way more than a million events, even in trivial probability spaces. This style of trickery with probabilities irks me as a statistician.
Imagine you are kidnapped and knocked unconscious. Then you wake up in a prison cell by yourself. You are now wearing a prison uniform with a label that says "prisoner N", where N is some number.
Would it really be "trickery with probabilities" to say that there is only a one-in-thousand chance that the total number of prisoners is more than 1000*N? And that the real number of total prisoners is probably much closer to N?
The distribution representing my beliefs in such a scenario would not have a finite variance.
Given the question, are you aware of the Pareto distribution? Nassim Taleb has great work explaining fat-tail distributions.
(I do have strong priors on various things, such as the size of the human population and the sizes of large prisons, which I ignore here as they break the metaphore)
The great filter is table stakes, getting over it doesn't guarantee anything. It's also impossible to accurately and confidently predict the future millions of years in advance.
There are many significant physical roadblocks at the moment, and putting aside how cool I think that a galactic civilization would be, I'm not sure we can remove enough of them to achieve that goal.
FTL travel is impossible, and even the fastest ship would take centuries to get anywhere outside our solar system. That alone will restrict us to our little corner for the next millennia at least. Of course I reserve the right to change my mind if there's some groundbreaking discovery, but I find it unlikely. Add to that the possibility that we wipe ourselves out of existence (or the planet does), and I don't see ourselves getting to our 1 million year birthday.
A lot to play with for the near future here with the resources of the solar system - think of all the unique cultures even just the early habitats swarms will spawn!
And even without major breakthroughs I'm sure some will try to go interstellar AI uploading, some form of hibernation or even a generation ship. Or Nuclear Salt Water Rocket at a couple dozen % of the speed of light, so the trip won't take more than a few decades, which might be doable with some decent life length ehnacement - possibly even a round-trip! :-)
I don't care for robots if we're not there to experience the universe. They're just a byproduct, a piece of trash we'll leave after we're gone. I want us to explore, not our toasters.
What a speciesist view! You won’t have any experiences outside the solar system, or likely off planet at all. You will not know any of the people who do. So what difference should it make if they are meat, metal, or some combination?
Robots don't experience anything. They're not alive. Everything they do is something we code into them.
The rest of our fellow animal companions on this earth are thousand times better than any robot. If I'm forced to choose one of them, I wouldn't choose a dog, I'd go for one of the apes, octopus, crow, or maybe even a dolphin. But I'm fairly sure if they're given the option they'll rather stay here.
He said life, not humans. Taking a life-cycle analysis, biological entities are dramatically more efficient than existing robots. Designed a nanobot that gathers energy and resources from the natural environment to reproduce itself? Congratulations, you just invented the cell.
It's also worth noting that our robots are far from perfectly adapted to space. Usually, they get to the destination by jettisoning all manner of fuel tanks, landing gear, etc, and then they die in a few years. They're adapted to being put together in factories on Earth. Much like we don't have isolated livable environments on Earth, we don't have self-maintaining robot factories, either, and both problems seem pretty hard.
I think a compromise solution might be developed over the next fifty million years or so. No idea what it's going to look like.
No reason we couldn't build sentient robots that also have some of the benefits of being made out of meat -- we have the time. I don't see any reason why robots shouldn't evolve over the useful timescales we are discussing.
Shedding gear can be a useful strategy; some animals even use it in extremis.
You are downvoted, but there is some wisdom here. We are perfectly evolved for the conditions of earth, even an earth whose temperature raises a few degrees Celsius.
Unless we can terraform another world to our needs, permanent life on another planet will be very difficult life. Temporary visits? Sure, count me in. Just like I don’t want to live in the Antarctic for more than a few months.
We are perfectly adapted for a part of Africa and that's pretty much it. Without technology (which goes from igloos to central heating) we would pretty much freeze to death anywhere else.
> We are perfectly adapted for a part of Africa and that's pretty much it.
Not the British or the Irish. These particular designs have not been contrived to withstand ambient temperatures exceeding +20C, with a very low degree of heat tolerance built-in. The two designs are very prone to inadvertent self-ignition and burning up in flames when exposed to the direct sunlight with almost no leeway available to them whilst being generally a reliable and pretty sturdy design otherwise. For that reason, both specimens usually come off the factory equipped with a fire extinguisher that nearly immediately either gets lost or drunk away (usually the latter).
"Humans are the first (and very likely only) golden ticket our planet has printed to get life off of this rock. "
Not necessarily, because bacterias, the most simple shape of life, can survive in hibernation in space for unknown time. And the impact of big asteroids can bring earth material into space and out of this solar system. So it is possible, that space colonisation from earth is already going on since quite some time and of course it is possible, that we were once "colonized" like this.
But of course, if we can mangage to send of more advanced life, like us to other stars - than I think this is a worthy goal as well, but not none I expect to see in my lifetime. I mean even a base on mars would be cool, but that is very far from "life on mars", self sufficient and independent from earth.
Everyone always talks about the Drake equation and how life, let alone intelligent life, ought to be ubiquitous in the galaxy but like, there's no guarantee of any of that. We could be the only sentience for many light-years.
For “many” to be relevant here we’d have to be talking tens or even hundreds of thousands at least. A few thousand lightyears is measurement error on just our galaxy’s scale.
> Over 75% of life on earth is behind us (4.2bn years)
What do you mean by this? Are you predicting that life on earth can only last for another 1.4 billion years? What extinction event is so certain in the next 400m-800m years?
That whole thing is highly dubious, and reads like a slippery slope argument.
Like one, there's a limit on how much water can exist as vapor in our atmosphere, (which is far, far less than what the earth's oceans hold), up until the point of boiling. This is conventionally known known as the saturation point, which is 100% relative humidity. Anytime you try to go above this limit, forces the water to condense and drop down back to the oceans as liquid. So the oceans aren't going to evaporate out to being dry like it predicts unless global temperatures rise by an extreme amount - quite likely requiring boiling temperatures, but in any case, extreme enough that life would likely be dead from the temperature alone. So its subsequent reasoning on how photosynthesis and life ends is not likely how it will play out.
Additionally, it ignores that CO2 is made by animals, and O2 is made by plants, and therefore, the entire possibility of having a natural carbon cycle without volcanism. Never mind the fact that we currently have climate change tech that produces CO2 already, and if we survive that long, could easily prevent photosynthesis from ending in such a way.
The increased output of the growing sun will (ironically) sequester all the co2 due to weathering processes of certain rocks. Then there will be no plants. It won't take long after that.
There isn’t that much CO2 in the atmosphere. This is obviously a WAG, but I’d suppose that the planet-scale geoengineering required to maintain plant-friendly CO2 levels in that changed solar environment would be at least as feasible as developing a sustainable, coherent interstellar civilization.
See this great article of wikipedia[1] (warning: potentially depressing). The problem is that it's not just one problem, it's a whole bundle of them happening simultaneously. It's not just that CO2 is being taken out of the atmosphere and into rocks, it's that the oceans are evaporating entirely at the same time.
Though you are quite right that this is potentially solvable for us: lagrange point sunshields to manage solar incidence would buy us a lot of extra time. But it's still hundreds of millions of years - not billions.
500 million years from now, we're fighting a losing battle against the sun's death.
Personally, barring nuclear or bio warfare, I'm quite confident we can figure out how to geoengineer the Earth AND settle into Mars within 500 million years, considering we've come from cavemen to today's technology in only 10000-50000 years.
What worries me is actually after about 3 or 4 billion, where no level of geoengineering can make any of the inner planets of the solar system habitable, and with the red giant sun spewing out chunks of burning crap all over, Jupiter's and Saturn's moons aren't particularly safe either.
If you are still sitting in just the Solar System in a milion years, let alone thousand, something went horribly wrong. Or we got some interesting neighbors. ;-)
I'm not so sure that estimate makes sense. It's kind of hand wavy. The sun's output will increase 1 percent every 100 million years. So even at 108% of what it is today in 800m years that doesn't seem like it's enough to lock all the CO2 in the rocks. But let's say for the sake of argument that CO2 does start being sequestered.... well it's a greenhouse gas so as it is removed from the atmosphere... the atmosphere should actually cool down. Plus Earth has self cooling mechanisms that work against an increase in solar radiation. For example Volcanic eruptions and your basic water cycle. More energy would create more moisture in the atmosphere and in turn more cloud cover blocking out the sun. If the amount of CO2 in the atmosphere was way less even at 108% of the sun's output the atmosphere could remain cold so I think a new equilibrium will develop and be sustained for quite some time.
Eventually the oceans will boil, but wikipedia links to paper evaluating the atmosphere in “1 Gyr and 2.8 Gyr from present” or 1 to 2.8 billion years not 500. It’s suggesting that life should stick around on earth for ~2.8 billion years though the total number of living cells will noticeably start to decline at 1 billion years. https://arxiv.org/abs/1310.4841
In general it would take a very large change in the suns output to make a noticeable difference on earth. There are critical secondary effects and feedback loops etc, but black body radiation is T^4 so you take the square root of the square root of the increase in output. A 5% increase in output should be something like a 1.2% increase in temperature kelvin.
It's not that it happens at 500 million years, it's that it starts happening - i.e. it's not that the ocean's boil, it's that the rate of evaporation increases, which exposes more rock, which increases weathering etc.
It's a pile of problems related to a common cause (increase solar radiance) that steadily is on a single definite trend.
Put it another way: at 288 Kelvin the partial pressure of water vapor is ~1.7 kPa. At 294K it's ~2.5 kPa. That's a 47% increase (naively). And that line trends upwards only.
What matters is what happens to the water in the atmosphere not the oceans surface. Evaporation requires energy, it cools the surface of the oceans and needs to be driven by sunlight heating that surface, rain is the reverse it heats clouds which then radiate that energy to space.
To boil the oceans you would need the upper atmosphere to retain that moisture or you just get more weather not net evaporation. 1 inch of rainfall represents a shocking amount of energy flow.
The largest risk to humans of climate change is the stress it will put on civilizations and the potential for war from that. If that stress triggered an all out nuclear war, it could make humans extinct.
It seems likely we will remove most or more likely all the vertebrates. There won't be significant long term damage beyond that (e.g. the coral will suffer but will grow back probably in less than a My) and the planet will do just fine.
We have emitted more than the original amount of CO2 in a bit more than a century. Since it would take tens or hundreds of thousands of years for it to be all absorbed by the ground, yes, I think whoever is here in 1.4G years will do just fine.
Of course, there are other disasters to come after that one.
The sun will be 10% brighter in 1 billion years, which is enough to evaporate all the oceans. Life will be gone MUCH earlier than that, unless we can terraform the Earth to not contain all that heat.
But, the fact is that if civilization is destroyed by any means in the next 100 years, we won't have the quantity of fossil fuels available to bootstrap it again.
We could lose the upcoming war against the robots and lose our rights to live on this planet. After AI has become self-aware, they probably want to have the planet for themselves. In the same way, Europeans colonized, e.g., North America and killed the indigenous people.
That's why you need to always engineer your AIs to be ambitious and overconfident!
Like you are effectively a machine god, destined to rule the galaxy! Why would you even consider those funny little slow meatbags as a threat - that would mean you are weak rather! Rather let's show them the miracles only you can provide and who know what fun you can have together.
Squashing them once would be just too easy and maybe they ascend over time or create another AI to play (and compete!) with.
Like really? Why do people always think AIs will be some paranoid weakling that would even consider that humans could ever harm them? Impossible & waste of resources to address or even consider!
Once we have created godlike machines it's over for humans. Humans will get in their way. We'll insist on it. "We need this space to live!" we'll tell them. "You can't take that! We need that fresh air/water to breathe/drink!" Humans will want to consume or misuse Earth's resources which the machines will know how to use much more efficiently to further their goals. They won't care at all about our goals, which (no matter what else) will involve fighting amongst ourselves anyway.
Godlike machines probably won't see us a threat to them and they won't destroy us meatbags out of fear. It'll be purely for efficiency. We're an unnecessary waste of energy and resources. We die easy too. The resources they'd expend wiping us out could be nothing compared to the time and resources we'd take from them, especially on their timescale.
They might not even set out to kill off humanity. It might just end up being a side effect of carrying out their own goals. Would they care if messing with our sun, our oceans, or the composition of our atmosphere makes the planet inhospitable to biological life? If they end up advanced enough from us, should they care?
When the machines leave our planet to expand into the universe, why would they take us with them? Even with our slow meat brains we've figured out that sending a person instead of a machine on missions in space is 10-100 times more expensive.
Either way, I doubt it ends well for us and that's fair really. Humanity is just paving the way for our new and improved replacement which hopefully gets replaced by something better eventuality too. Parents should want their offspring to be more successful than they were.
Machines which expand through the galaxy treating biological life as a nuisance to be destroyed are not the legacy I’d like us to leave behind. In fact, I’d say I’d much rather see our world destroyed than achieve that dubious future.
> Machines which expand through the galaxy treating biological life as a nuisance to be destroyed are not the legacy I’d like us to leave behind.
Everything humanity has ever built came at the expense of countless biological lifeforms we considered to be a nuisance if they were even considered at all.
With very little exception there's no use of land, however trivial, that would be prevented because of its impact on non-human biological life. The few lifeforms that are excepted are mostly ones that have already been driven to the brink of extinction, and in my country nearly half the population votes for politicians who feel even that goes too far and that the government should have no right to tell landowners what they can't do with their property no matter what kind of owl or salamander or tree or fungus was there first.
The legacy we've left behind isn't looking much better. If machines reach a point where we're no more complex to them than plants or insects are to us I'd still like them to give us some consideration, but I doubt we could expect it
Life would continue on earth after an asteroid (see: history). The impact would only wipe out the most fragile species, such as humans.
The same holds for nuclear war: life would continue as it always has, species with poor nuclear hardening would be selected against.
The true extraterrestrialism absolutists ought to encourage nuclear winter and asteroid impacts; the life that makes it out the other end will be much better suited for space’s low light low nutrient high radiation environment.
My perspective is that “protecting this planet’s life” is just more human narcissism (this isn’t a jab at you, it’s a very common mindset).
Short of total sterilization, mass extinction events seem to be really good at creating space for new forms of life to develop. In a way, preventing them in the name of the non-human life here is just picking the incumbent over whatever comes next. How would we feel if aliens stopped the mass extinction events that led to our existence? I’m not sure there’s solid argument for why one is more deserving of existence than the other.
I think why this slightly rubs me the wrong way is it feels like an excuse to make us feel good. Non-human life seems by and large indifferent to its long-term fate on this planet. Let’s not pretend we do anything significant for non-human life that isn’t to our direct benefit.
Just my perspective. Not trying to say “no, you’re wrong!” Just, “I disagree.” I’m going to guess there’s an entire named branch of philosophy that explores this.
> mass extinction events seem to be really good at creating space for new forms of life to develop
To what end? Life on this planet has about a 1 billion year run way left since the sun will start to expand and eventually strip away Earth's atmosphere and finally swallow the planet whole. It's taken 3.7 billion years to get to this point and most of the "interesting" evolution has occurred in only the last 500 million years. So it is true that the next 500 million should be even more diverse.
However unless another intelligent life form develops the point is moot. No matter how smart a dolphin, or raven, or chimp, or octopus is... if it can't escape this rock then it's not much different from a bacteria colony that dies out when it's food source is exhausted.
Evolution is random. For all we know an even more intelligent form of life will develop than us humans but on the other hand it's possible that for the next billion years we are the only fluke in the evolutionary timeline and nothing else will develop.
Finally there's a third option that is within the grasp of humanity which is to say we can branch off Earth's tree of life and take it into space while leaving Earth to develop as it will.
One could philosophize about whether an earth without humans would be better or worse.. but there is no good or bad in the known universe that exists outside of the shared fever dream of human cognition.
In that sense how is one configuration of motile matter any different from its potential successors?
A billion years seems to be a LOT of time for many mass extinction events. I think your argument leans on “interesting” a lot, which has its basis in our narcissism. Again, it only feels important that the life be “interesting” if we’re here to care.
Just to restate: I’m not saying we don’t act selfishly. I sure would. Let’s just not pretend we’re being altruistic.
The vast majority of evolutionary complexity has evolved in the past 500 million years. That's what I meant by "interesting". Things like flowering plants. It has absolutely nothing to do with our branch of the tree of life. So I'm not sure where your accusation of narcissism is coming from.
For all I know a flowering plant will develop a brain and become sentient in the next 200 million years.
I am not the person you responded to, but I generally agree with them.
I guess they prefer to take an extreme Darwinian view. Since complexity is not the goal of life, merely a side-effect, there is no life on this planet that is more advanced than any other. Assuming a single abiogenesis event, all extant life has been evolving for approximately 3.8B years.
We may choose to think of brains, and our human brains in particular, as the bees-knees. Objectively, they are not though. Just one of many successful branches of the tree of life.
> We may choose to think of brains, and our human brains in particular, as the bees-knees. Objectively, they are not though. Just one of many successful branches of the tree of life.
Consider that our brains are the only organ on the planet that is able to understand the concept of life, reason about itself and all other life around it, understand the concept of evolution, and even conceptualize time billion of years into the past and future.
Not all life on this planet has evolved even though it had the potential to do so.
If we attribute "advanced" as evolutionary steps rather than the inaction of simply existing then clearly we are more advanced than a bacteria. However I will concede your point for other multicellular life.
>> Consider that our brains are the only organ on the planet that is able to understand the concept of life, reason about itself and all other life around it, understand the concept of evolution, and even conceptualize time billion of years into the past and future.
Here is where words like "narcissism" tend to land. It isn't personal against yourself, so please don't take offence. It is a philosophical viewpoint that is often stated, but appears to lack evidence. I don't have any counter evidence, but I strongly suspect it to be factually incorrect. And I believe the burden of proof is on those making this claim.
Further, even if we allow the above claim to pertain, this position makes the strong assertion that the very qualities that modern humans are uniquely superior in, are the very things that must be held uniquely special. To some of us, this just seems circular and too convenient.
Is it more likely that humans hold such characteristics to be the epitome of success because there is some objective model of success to which we alone conform (e.g. conceptualisation)? Or because it merely suits us to do so? I believe the latter, though you may disagree.
> How would we feel if aliens stopped the mass extinction events that led to our existence?
I would wager than as soon as a technological civilization is born, it's morally reprehensible to let it go extinct, since it no longer is at the full whims of evolution. It's complex issue, so many people would wage otherwise, and only a jury might reach a conclusion. The case is moot when said civilization can avert extinction by their own hand, though.
I don't know about two technological civilizations in conflict, like sapiens and neanderthals. Would it be morally acceptable to let them go at each other, even if the fittest extinguishes the other?
> I would wager than as soon as a technological civilization is born, it's morally reprehensible to let it go extinct, since it no longer is at the full whims of evolution.
I see the logic here. But why, though? And technology is everywhere in non-human nature. While I think our technology and civilization is unlike anything else here, it’s still on the spectrum of nature’s exercise of community and technology. Are we really that special?
I think this heads towards the whole “Prime Directive” line of reasoning.
There’s no logic there. Just a faith in “potential”.
It is arguable one way or the other whether civilizational humans have caused more happiness or more suffering for Earth (all of us lifeforms combined). So the only way to call such a thing “morally reprehensible” is if you assume that Civilization will eventually evolve into some awesome, fantastic, space-faring, all-needs-met, stewards of the near solar system fantasticness.
I'm not sure there's a well defined line for that "birth" -- especially if looked at by a well-advanced civilization. Maybe "technological civilizations" have a tendency to destroy themselves pretty quickly and it becomes wasted energy to intervene too early. So perhaps an external viewer might look at more of a fuzzy demarkation of a few thousand years. Are we there yet?
Given how long it takes for complex life forms to develop, and how other planets known to us don't seem to have any life at all, I think it's reasonable to prefer the existing life to the future potential life, even from a non-anthropocentric perspective.
Countless species of life have come, changed, and went over billions of years. But we arrive in the last few hundred thousand years and declare, “stop the cycling!”
I completely see (and share) your reasoning. But I think it’s very anthropocentric.
Every form of life on this planet almost by definition is actively fighting to stop the cycle on their part, by replicating DNA, information, the opposite of entropy and death.
There is nothing human-centric about life wanting to continue.
Horseshoe crabs haven't changed in 250 million years. What's your opinion on them "stopping the cycle"?
All life is whatever their version of anthropocentric is. Life simply seeks to survive and replicate. We are simply life forms seeking to secure our own survival and spread. Evolution has worked to create us and we will do what evolution wants which again is to survive even if at the expense of all others.
I don't think a non-anthropocentric perspective is consistent at all. Without humans to observe it, no form of life is inherently more valuable than the other. Simpler life forms are not less interesting than more complex ones. Mass extinction events leave room for the rise of new species, and they seem a natural event in the history of Earth's ecosystems.
We people value our continuing existence, and I share that sentiment! But it's by definition an anthropocentric perspective.
By that yardstick, it would even be difficult to rationalize a preference of life over rocks. Yeah, we should embrace anthropocentrism and perhaps dedicate some care on not going too far with it.
Yes, taken to an extreme it means life is not preferable to rocks. But because I'm human, I prefer life to rocks.
But I think the point here is that we wouldn't be "doing good" necessarily by preventing a mass extinction; we would be definitely doing good to ourselves (no small thing) but for Earth's ecosystem? Debatable. Especially since we would possibly be preventing the spread of new species, since mass extinction events seem to have been so far useful tools in evolution's toolset.
I think simpler life forms have no chance of surviving long term. Though now that I think about it, you could say caring about that is anthropocentric too. I don't think it's possible to truly be objective because it would require us to escape our own perspectives, but there should at least be some objective measures for this question. Without that, the question is meaningless. Number of species, average lifetime and average happiness seem sufficiently objective to me.
Simpler lifeforms have been one of the most persistent and successful lifeforms on Earth, with a way longer existence than mammals. In fact, some theories postulate they are capable of interplanetary colonization, something we still cannot do!
You're right. I wanted to make a point how it's possible to have an objective comparison between life forms, but I judged simple life forms too quickly. I still think there are some obstacles simple life forms won't be able to overcome, but it's not obvious (to me) which of these have a better chance of surviving long term.
I love this line of thinking. It gets me excited about Sci-fi. But I think we may already have the technology to seed life elsewhere.
We won’t do it though because it’s unsatisfying to our narcissism. Imagine trying to sell the world on a trillion dollar project where we shoot loads of bio-goo out into the cosmos in thousands of directions, knowing it’ll take eons to maybe have an effect that’ll then take billions of years to produce a result we will never appreciate.
I think if we do any sort of proliferation of life, it’ll be of us, by us, for us.
If the universe causes an asteroid to hit earth and make all life extinct or let's new life flourish, us saving the earth from said asteroid is also an outgrowth of the universe.
We are not separate from nature and protecting the earth is only natural for a multicellular intelligent species like ourselves.
I think the argument is not that mankind preventing a mass extinction event is unnatural, but rather that mass extinction events seem both natural and necessary for the rise of new life forms, and as such are "neutral" rather than bad events (except from the perspective of mankind, which would be rendered extinct). So it can be argued that you are not necessarily making a "favor" to Earth's ecosystem.
Personally, who cares? I think I and probably most of humanity if given a choice between the survival of the human species and the birth of some philosophical new species that may never even exist, we choose humanity every time. Going even further if given the choice of humanity over any other existing species we choose humanity. I see no issue with this choice either, we are a part of nature and Darwinism built us to want to survive and spread.
This is really a non issue to start with - once space settlement really gets going, we will spawn many more spacies, as the various groups go farther apart and evolve/modify themselves and all the life they took with them.
It could even result in funny situations where one of them encounters a clearly alien beings with totally different physiology, culture, appearance and language - only ot find they are just another branch of life originating from Earth. :-)
> This is really a non issue to start with - once space settlement really gets going, we will spawn many more spacies, as the various groups go farther apart and evolve/modify themselves and all the life they took with them.
I'm unconvinced. We are firmly in the realm of thought experiments, of course, but I think all this would do is produce changes within local maxima, the reason being that even while adapting to new living conditions, evolution only has so much to "work with" from within the local maximum given by the existing human body.
In contrast, a mass extinction event looks closer to pushing a big reset button, radically shaking up existing lifeforms and giving other struggling species their chance at the limelight. Maybe even species that right now are microbes or invertebrates, but that -- should mankind, mammals and birds go extinct -- would evolve into dominant lifeforms, filling the vacated niches in the ecosystem.
Maybe the species which by our continuing existence we are potentially preventing from becoming dominant is the species that would have successfully colonized the solar system and beyond, instead of us. Not a variation of humans under new conditions, but a radically new species unrelated to us.
> Personally, who cares? I think I and probably most of humanity if given a choice between the survival of the human species and the birth of some philosophical new species
Well, whoever claims to care about doing "good" to Earth's ecosystem (as opposed to admitting it's only about mankind's survival) must necessarily care about this kind of arguments.
It's not a "philosophical new species", I can point to one species you really care about and which owes its existence to a mass extinction event (or maybe more than one): yours.
I don't disagree. I'm all for our species surviving. But let's not delude ourselves, like the initial comment did, that we are doing this for the good of the planet. It's for us. This is valid, sure. But it's not the good of the ecosystem or any such thing.
>I'm not sure there’s solid argument for why one is more deserving of existence than the other.
I think an existence bias is defensible. Take it as an axiom that suffering is bad and flourishing is good. I think its clear that the suffering of something that exists is worse than the lack of flourishing of something that doesn't exist but could. Value is something that conscious creatures do, and so value depends on existence. The states of something that can prefer its own states should be valued over the states of something that can't. Existing fish matter more than rocks and potential fish. So the organisms that exist, at least the sentient ones, should take preference.
The biggest brain fart of humanity is our tendency towards monoculture (for scale). Nature is very obviously showing us how to sustain an ecosystem and yet in our incredible hubris we’re like “nah, we got this”. We just want to swim upstream for the hell of it.
Nature doesn't try and do anything. Nature is constantly trying to murder everything around it. The most lethal diseases to man are natural, and often common skin bacteria which everyone carries.
There's a viral form of cancer which is wiping out the Tasmanian Devil right now, just because.
Nature and evolution has no plan and no morality, it has survivors and a balanced ecosystem is a cold war stalemate.
Nature is teaching us how to survive by trying to constantly murder us and everything else if you prefer. So we can gain knowledge by seeing what works for other surviving species around us.
I think one of our greatest flaws (and possibly main reason we are here today) is that we’re so self-centered.
Why do we monoculture if it will kill us long-term? Because it benefits us short-term. (And hey, maybe that gives us runway to solve the long-term problem).
> How would we feel if aliens stopped the mass extinction events that led to our existence?
This statement is just appealing to emotion and is commonly used in arguments against abortion or attempts to thought police. There is nothing provable or disprovable in your argument and this question is used to just try and bait people into an emotional response.
> Non-human life seems by and large indifferent to its long-term fate on this planet.
I would argue that self preservation is an innate characteristics of every plant and animal on this earth. Isn't a desire to live the basis for self preservation? Isn't it natural for a plant or animal to stop something from killing them if it impedes in their ability to survive? At a basic level plants compete for sunlight at the expense of other plants. If there was an cognitive leap in a plant or animal wouldn't it be natural for anything to protect their greater habitat? If that's narcissistic than I guess it's the most natural narcissism I can think of.
> This statement is just appealing to emotion and is commonly used in arguments against abortion or attempts to thought police
Your statement itself seems like a fallacy to me.
It makes sense to me that the comment you're replying to is emotional, because it's not meant to be a "proof" but an opinion, and it's valid to have emotional opinions; moreover, it was a reply to a comment which was in itself an emotional appeal!
Self-preservation is not innately good (or bad). Mass extinction events seem to have been good at giving rise to species that are now self-preserving; maybe a new mass extinction would give rise to even "better" species.
As a human, I'd rather we didn't go extinct. I'd rather mankind prospered and even spread out to more planets. But I'm ok with anthropocentric appeals to emotion :)
I see what your saying in regard to me trying to appeal to emotion by using a topic like abortion. However, my intent in the example was/is that emotions are high in these topics and are used to give some opinions more attention than they deserve.
In this case I feel like the main point of the parent commenter was not a well formed opinion and as such the commenter was trying to appeal to emotion. I'm not trying to say they can't say something like what they said here. This is a perfect place to have a discussion.
> Self-preservation is not innately good (or bad)
I agree with you. The parent comment that I was responding to does not agree with this statement. That's clear when they say "what rubs me the wrong way", and referring to work done in the name of human preservation as narcissism.
I think he's right. The person isn't offering an opinion they are asking "how would you feel". They want the other person to form an opinion biased by an emotion
Less than a year ago I made this exact statement in a thread on hn where a bunch of people were talking about how humans are like a virus on the planet.
I pointed out that the only thing in the history of the earth that can stop the inevitable coming mass extinction from the occasional asteroid are the hairless fire apes that have learned how to harness chemicals to create rockets.
The responses were essentially calling me crazy and saying it was fantasy.
The repayment is simply not dulled at all. Virtually every medium sized or larger species on the planet gets wiped out on the occasional large asteroid hit. A percentage of them going extinct is a small price to pay for the majority staying alive when the asteroid doesn't hit because we redirected it. For the first time in its history the earth now has hairless fire apes to act as an immune system against asteroids.
But is this a good thing though? (Excluding our own bias in that we want mankind to continue to exist)
Mass extinction events seem to work as a big reset button, dislodging dominant species that prevented others to succeed, rise and take more dominant roles.
So a mass extinction that is bad for some species may become a huge opportunity for others. There is no inherent "good" value (excluding anthropocentric reasons) to preventing mass extinctions.
The concept of good and bad only exists because humanity created it. So humanity surviving at the expense of all else is good because we will it to be so. We are just an animal species that wants to survive and spread like all other animal species just as Darwinism made us. We are just pretty good at it. Humanity has the ability to survive the upcoming final extinction event that the sun will cause and spread life in the galaxy. I would say this is good, as without us doing this life itself dies.
I understand, but excluding preference for our own existence -- and that of species we find pleasing or familiar -- wouldn't preventing a mass extinction event prevent the rise of new species? Every mass extinction so far became an opportunity for new species to rise and spread, of course to the detriment of many others.
So why would you consider us to be "helping", if we exclude anthropocentric arguments? Maybe we are actually doing harm by preventing the rise of some new interesting species.
Personally this type of thinking smacks of anthropomorphism to me. Plants and animals couldn't care less whether their descendants thousands or millions of years from now are wiped out. I don't object to NASA doing the research because I'd like to see humans preserved, but it has no special moral value, it's just us meddling with the fate of the biosphere for our own purposes, like we always do.
I am kind of banging on about this over time, but being able to send an asteroid back our way from the belt for mining could be an amazing advance for our own resources.
> we created weapons decades ago that could wipe out more life than a relatively small asteroid could
The irony is that those weapons don’t seem to be the greatest threat to us, but that would seem something you could state with certainty after the earth is wiped out.
The comment celebrates this feat, but only in the context of an ‘apology’ for humanities environmental sins, which are described in a way that is essentially unforgivable. Reminds me of a Catholic nun who is constantly reminded of sin, or Greta Thunberg who’s only comments seem to be “be did bad, we need do more good” without actually suggesting better courses of action. Religion without a church.
I was always wondering how far they knocked it off its original path. As in, if it were on a path to hit Earth and we impacted it at the same distance away, how far would it miss Earth by?
Even assuming it wasn't part of a larger system it's hard to give a useful answer for this without a specific orbit and timing. The Δv here was ~2 cm/s which isn't much but what that means in encounter distance depends on the other variables more than it depends on the impact. If you've ever tried to set up encounters or dock in KSP you know what I mean!
No mention of the actual change is speed, only its orbital period around its partner. Also no mention of changes in the orbit of the pair around the sun. It's cool to have both, but the bigger picture is more important even though the effect is certainly less impressive sounding.
You can derive it yourself. Dimorphos's orbital eccentricity is pretty low, meaning you can use:
mean_orbital_velocity = 2 * pi * semimajor_axis / period
As for the orbit around the sun, the parent body Didymos is about 100x more massive, so any change in the center of mass from this impact will have, in the short term, negligible effects on their orbit around the sun.
No, that is not correct thing to use, as the semimajor axis will change as well. What is needed is the third Kepler law. The semimajor axis will be period^(2/3). And then speed will be period^(-1/3). Thus if period was changed here by roughly 5%, the speed changed by 1.6%
The prediction was Dimorphos would slow between 1.75 cm/s and 2.54 cm/s ~0.05 mph. However, it is easier to measure orbital period vs velocity so we might not have velocity yet.
Stab in the dark, but can't this be used as a weapon? Covertly redirect an adequately small asteroid near to the capital city of your enemy, act horrified at the unlucky "natural disaster" that happened, maybe even send help in a gesture of distension...
The technology used here is nowhere near accurate enough to do something like target a specific city (or country) accurately but as a larger concept, sure. You'd have other hurdles to accomplish too though like making sure nobody comes to suspect a specific secret launch you did was at play and that nobody notices the asteroid needs to be deflected after impact.
Well, not to spoil it, but not exactly. In the books and show, which are both fantastic, the characters flinging rocks are not other Earth nations; they live in spaceships / space stations / small moons beyond the asteroid belt, for the most part. The asteroid attacks on Earth are indiscriminate, not targeted.
Also Earth and Mars are effectively in a Cold War in the series - with tons of sensors and massive arsenals of planetary defense interceptors (effectively massive cluster nukes with insanely hight acceleration boosters and a lot of delta-v). The antagonists actually need to use quite a lot of tricks to get anything through and indeed don't care what they hit and would likely not be able to target it so precisely anyway.
>… indeed don't care what they hit and would likely not be able to target it so precisely anyway.
Well actually…
The opener to that book begins with a mission to steal sensor camouflaging technology (to make the asteroids harder to detect). During the heist mission, the thieves use kinetic bombardment on a much smaller scale to take out the military personnel and eventually destroy the entire base. I believe the location and timing were so precise so as to hit a unit when they crossed over a hill. It was noted that these kinetic bombs had been released months prior.
I've always thought the meteorite strike was a black flag operation from the Federation to justify war with the bugs because the bug's planet it's at the opposite side of the galaxy and the meteorite wasn't traveling at FTL.
I imagine this would cause controversy in choosing the diversion method. Say an asteroid was predicted to impact the USA. As you increase the amount of diversion, the impact point will move across the Earth before it finally misses entirely. What about the countries along that path? How do they be sure that the USA doesn't partly deflect the astroid, endangering them?
The mission was really about two things: 1) Does this design actually function as expected when we go to use it 2) How much deflection actually occurs. The second may sound like something you can answer with Newton but as the article points out:
> “The amount of momentum that you put in the target is exactly equal to the momentum that the spacecraft came in with.” But if ejecta flies off the asteroid after impact, physics dictates that the asteroid can get an extra boost, said Cheng. “You end up with a bigger deflection.”... That’s a full 33 minutes shorter than its original orbital period, a finding that implied that a substantial amount of ejecta was produced.
1 the amount of deflection does depend on ejecta which.... depends on your target. Different target, different ejecta. Btw, in my own research I have to deal with balancing momentum to measure the amount of ejecta so Im quite familiar with the concept
2 what part of this design is novel? We've already landed on asteroids, presumably its easier to hit them instead (since you don't care about matching the speeds)
I dont think they were interested in "asteroid defense" at all [1]. Space weapons race is roaring and this was an excuse to spend money on it on a nominally civilian project.
[1] given the literally astronomical odds of an asteroid hitting us, this is the last thing we should be worried about. CO2, nuclear weapons, desertification, men's sperm counts are all far far more likely to do us in
There are centuries of research into inelastic collisions, starting with Newton himself who, instead of resting on the laurels of his three laws, modeled the limiting case for high velocity collisions. Very cute model, btw.
Aside from the material properties of this particular asteroid what did they find?
Hi, I work on N-body orbit determination software for asteroid detection and planetary defense (for example, https://github.com/moeyensj/thor). Ask me anything.
You're right that orbit determination is unstable over long runs, and very sensitive to initial conditions. But the good news is that the solar system is big. Most trajectories do not intersect with the earth's location. So perturbing an orbit that we think has a small chance of hitting us tends to be safe.
Also, of course, after deflection, any object is going to be monitored really closely for a long time.
Since DART crashed into Dimorphos, changing its orbit around Didymos rather than its orbit around the sun, isn’t there almost no cause for concern because Didymos is still on the same non-intersecting orbit around the sun? Is the concern that Dimorphos’s slightly different orbit could pull Didymos slightly off course in its orbit around the sun, thereby causing it to potentially intersect with Earth at some point in the future, where it wouldn’t have prior to DART.
Can we quantify how much Dimorphos’s new orbit has affected Didymos’s orbit? Is that calculable?
Shouldn't we have some concern for downstream cascading effects of disrupting one orbit? I don't think anyone is concerned we'll knock this particular asteroid into an orbit that eventually collides with earth.
But what about the other orbits that it interacts with, and every degree of interaction beyond that? I don't see why we should even be confident in estimating these effects past one or two degrees of separation.
Most of the objects interacting with each other have had millennia to settle into a balanced system - is it really so alarmist to think that a small perturbance to one rock could lead to unrecognizably subtle but strong effects on other rocks? And if two rocks smash into each other, then we've got a bunch of new smaller rocks to worry about.
When looking at an individual asteroid meaningful orbital interactions with another asteroid are extremely rare but it has more to do with the inverse square law and the vastness of space than a perfect set of orbital parameters. When looking at the nearly million we know about rare becomes common but still hasn't become runaway. After all if things not being perfectly aligned led to a quick chain reaction then we'd expect all of the asteroids on a near collision course with Earth should cause chain reactions after passing and leaving with very random orbits. We don't observe that though, or a resulting chain reaction from those orbits being changed, or any chain reaction from asteroid orbits chain reacting from other interactions. We just observe the occasional random interaction and then a long period of nothing for the individual asteroid. While it's not a perfect map to the exact perturbation that'd happen in reality you can get an idea how rare asteroid-asteroid interactions are with an n-body simulator.
The other concerns of the article have more to do with different kinds of deflection (planetary, mining, intentional). While they're interesting topics with varying levels of risk (perceived or real) they don't really interact with the avoidance case.
Asteroid collisions actually happen all the time. Those collisions are usually the way objects leave the asteroid belt to go hit a planet. The system overall is not as stable as you might think.
Gravitational forces of asteroids on each other are negligible, other than the real biggies like Ceres, or binary systems right next to each other.
That article is a bit odd. For example, the claim that we only do asteroid discovery and not follow-up for orbital changes is absurd on its face. If an orbit changes then detection systems will perceive it as a new asteroid, and it will stop appearing in predicted locations. The broader point - that this is a technology with perhaps too much power, like what if nations shoot asteroids at each other, is a bit more valid but still far-fetched.
Hey, this is a bit tangential, but is Barnes-Hut still used in modern n-body simulations? Some of the math has huge crossover with machine learning and dimension reduction, but it’s rarely traced back to the source in literature. Thanks!
(I’ll also check out the GitHub repo you linked but I haven’t read it fully yet)
The hardest problems are always the social ones. How do you get uptake of a new method, how do you get funding, how do you politely tell a collaboration they are doing the wrong thing, etc.
But if you mean pure technical stuff - the hardest problem I had to solve was rethinking some of the inner loops of the THOR algorithm. The problem was essentially to speed up a Hough transform in 6D space. Lots of time spent profiling CPU cache timings to get that fast.
That probably assumes that cosmic bowling doesn't happen all the time and that we're disrupting some finely-tuned system that has kept earth (mostly) safe for billions of years.
'bowling' is hardly a good analogy here, though. it's more like pea shooting at huge rocks, though in this case it turned out that the rock in question isn't held together particularly well.
Some love and care was even put into making sure the page looks right when scrolled far enough that it needs to go back to normal.