Struck by this part about the island’s sense of loss of the telescope:
> Arecibo’s prowess at astronomy was a source of pride in Puerto Rico, and many have been disappointed with the NSF’s decisions.
Such a contrasting view compared to the long fight in Hawaii over the Thirty Meter Telescope project [1], where locals have continually fought and protested. It’s tied up in the Hawaiian sovereignty movement, and a lot of cultural connotations, but I can’t help feeling like the Arecibo case should be a lesson for the TMT movement: you’d miss the telescopes if they went away.
> It’s tied up in the Hawaiian sovereignty movement, and a lot of cultural connotations
I mean I think this is underselling it a little. It seems like the main difference is that Puerto Rican colonization and subjugation started like 350+ years before Hawaiian overthrow and annexation, so there are just very few descendants of indigenous people left in Puerto Rico. Conversely, a significant portion of Hawaii is descended from indigenous people, and some of them probably had grandparents who grew up in an independent nation and remember them talking about it. The wound is still relatively fresh.
I think what happened with TMT would have also happened with Arecibo if the Spanish hadn't already killed nearly all of the indigenous people, to be blunt. It's definitely about sovereignty and not about a distaste for telescopes. There's a lot of infrastructure I'd like to see built in my own country, but that doesn't mean I want another country to invade and then build it.
Only a portion of the community still actively talks about the overthrow. Many Native Hawaiians also support the TMT.
>but that doesn't mean I want another country to invade and then build it.
A lot of the people who overthrew Queen Liliuokalani were subjects of the Kingdom [1]. It's a common propaganda point of the sovereignty movement to just label them as Americans, to imply they were some foreigners that just came in and overthrew the Queen. The calling in of the Marines wasn't really sanctioned by the US and later on the US attempted to give Hawaii back to the monarchy.
The sovereignty movement like to play it like the US just invaded, took over the land, and forced out the Native Hawaiians, just like they did with tribes on the mainland. But that's really not true at all. More importantly, it has nothing to do with Maunakea, as the mountain itself never really belong to the people.
I did not mean to imply that all native Hawaiians agree about this, it's a big population so obviously there will be diversity of views. My main point was just that there are native Hawaiians in significant numbers at all - there are some descendants of Taino in Puerto Rico, but very few and it's been centuries since they were independent.
I understand there is some debate about how involved the US government was in overthrowing the Hawaiian government. It seems like everyone agrees that there was a coup with the express purpose of achieving annexation by the US, the majority of Hawaiians did not support annexation, and the US government did it anyway. That happened relatively recently, a lot of people are still mad about it, and it's a legitimate thing to be mad about. The US took over a weaker nation against the will of its people. The most generous view we can take is that a minority of Hawaiians requested annexation and the US agreed, which would still be unjust.
I don't think historical details about how exactly the coup happened are relevant to this discussion, and if they are I'm definitely not qualified to argue about them.
> Whereas, in pursuance of the conspiracy to overthrow the Government of Hawaii, the United States Minister and the naval representatives of the United States caused armed naval forces of the United States to invade the sovereign Hawaiian nation on January 16, 1893, and to position themselves near the Hawaiian Government buildings and the lolani Palace to intimidate Queen Liliuokalani and her Government;
And while you’re learning about this stuff, make sure you follow the rabbit trail far enough to get to this little historical backstory:
> In 1899, industrialist James Dole moved to Hawaii. James was the cousin of Sanford B. Dole, who had helped overthrow the Kingdom of Hawaii in 1893, and became the governor of Hawaii in 1898. Two years after James Dole's arrival, he formed the Hawaiian Pineapple Company (HPC).
Indeed fruit companies have been a major force of colonization. The house I grew up in was built on the former estate of Minor Cooper Keith, one of the founders of the United Fruit Company, now known as Chiquita.
The term "Banana Republic" refers to UFC's complete domination of most South American governments through criminal activity.
And for something more up-to-date, this guy does threads about it regularly https://octodon.social/@silverspookgames/109943715639028256 He made a video game called Neofeud that skewers a bunch of things he saw happen growing up in Hawaii, but in a cyberpunk setting.
Insofar as I'm aware, Arecibo is not a sacred site to indigenous Puerto Ricans. Nor was there any concern about barring local access to the site, which had been available for literally centuries (excepting, of course, the historic bans of all but the most senior members of Hawaiian society - again sacred site).
I'm generally pro-telescope, and I've worked with people who have spent a lot of time at Mauna Kea (Keck, especially). But the more I learn about this, the more the Mauna Kea telescopes feel an awful lot like Mt. Rushmore: colonists moving in and saying that the natives' claim to a place is less legitimate than whatever "progress" the colonists have planned.
I'm really torn about this. Mauna Kea is the best place on the entire planet to observe the galactic center; it has the best seeing (minimal humidity and low atmospheric turbulence) that's not matched in the northern hemisphere. The ESO already has an equivalent observatory planned in the southern hemisphere so there's less value in relocating the TMT down to Chile, so effectively either Mauna Kea or nowhere.
Simultaneously, Hawaii has an ugly history of colonization that's not talked about enough. The area is sacred to native Hawaiians and indigenous people deserve say in how their ancestral land is used. The TMT is also a comparatively easy target for activists to push back on colonization compared to large corporations with continents of lawyers, or the tourism economy that provides revenue for the island. Folks know that chaining elderly folks across construction access works, and it would be a PR nightmare to forcibly remove them.
Scientific progress should be something that transcends politics but we're stuck with the legacy of colonization, and that makes us all a little poorer.
Regarding the Native Hawaiian's say, they do. This is a liberal democracy, and their voice is heard, quite loudly, especially the fraction that support the sovereignty movement. If we start parceling out the use of public land by ethnicity, we go down a dark road. But from an electoral point of view, the Office of Hawaiian Affairs is an elected body, and in recent history those that are either pro or neutral on the TMT have been getting elected.
>The TMT is also a comparatively easy target for activists to push back on colonization compared to large corporations with continents of lawyers, or the tourism economy that provides revenue for the island.
That's true. They are picking on an easy target that is not harming them or their movement. They are delaying progress for an idea (sovereignty) that most of the people in Hawaii do not agree with. It's politics impeding science, yet again. But since it's done from the "right" side of politics, it seems to get a pass from people where it would not be in other instances.
Thank you for correcting me on how things are right now. The uniformity of resistance to the TMT has not been clear to me.
I will say that I don't think it's a question of the "right" side. Rather it's a question of trying to right a historic wrong, and to practice what the US preaches. Absent all else, I'm pro-telescope. I worked with a bunch of people who collected data on Mauna Kea, and one of the few astrophysical publications I worked on used data collected at Keck. But the history of American colonization is much too recent to ignore, and I think every interaction with native Hawaiians is necessarily done in the shadow of that history.
A through line of American interventionism is the claim that small nations ought to be free to chart their own course (be it freedom from Spain, or communist Russia, or the concept of communism). I generally advocate for the US to practice what it preaches, because another through line is that the US almost always operates according to the idea that it's only self-determination free of foreign meddling if the small nation works in concert with American ambitions. Queen Liliʻuokalani was overthrown in the midst of a campaign to restore suffrage to her subjects. The colonizers had previously forced her brother to sign a constitution that stripped most native Hawaiians of the right to vote in their own country, and grant the vote to non-native, non-subjects with sufficient wealth and/or land holdings. That constitution is frequently called the Bayonet Constitution because of the circumstances surrounding Kalākaua signing it.
>Rather it's a question of trying to right a historic wrong
But blocking the TMT won't do anything to further that goal, as it has nothing to do with it.
> But the history of American colonization is much too recent to ignore
> The colonizers had previously forced her brother to sign a constitution that stripped most native Hawaiians of the right to vote in their own country, and grant the vote to non-native, non-subjects with sufficient wealth and/or land holdings. That constitution is frequently called the Bayonet Constitution because of the circumstances surrounding Kalākaua signing it.
I'm familiar with the Baynoet Constitution but I take issue with the blanket use of the term "colonizer". As far as I've seen, it's been used by the sovereignty movement and their (largely) progressive supporters to mean anyone at the time (and even today) that lived/s in Hawaii and is not Native Hawaiian. Many of those that were involved in the overthrow were subjects of the Kingdom. They and their families, not to mentions all the non-Hawaiian plantation workers - came there legally and were even encouraged. The sovereignty movement would have you believe that the story of Hawaii is exactly like the story of mainland tribes, but it's just not true. There was no colonization in the way that it happened on the mainland and the use of the Marines in overthrowing the Queen was illegitimate, even per the US government. A lot of the issues with Hawaii and Native Hawaiians can be traced back to the Kingdom times (but not all).
In any case, this is the major problem. People are trying to litigate past political issues by involving the TMT, a scientific project that has nothing at all to do with it, on a mountain that also had nothing to do with it and never really belonged to the public until after the monarchy.
If you compare what happened in Hawaii vs. a variety of e.g. African colonies, the crucial difference is the absence of blood in the final fall of native Hawaiian rule.
Its kind of irrelevant that the Marine intervention was illegitimate, since the US government still accepted the new regime as legitimate. A lot like the US's eventual intervention in the Black Hills, after settlers ("colonists" if the parallel is too opaque) illegally entered the area and then required protection from the natives they were displacing. If my kid steals a toy from another kid, and all I do is say "gee, sweetie, that was mean", but I don't force my kid to return the toy, its still theft.
Its also irrelevant that the coup was led largely by Hawaiian subjects (6 subjects, 7 foreigners, according to wikipedia), since the committee of safety was, to a man, non-native, whose explicit intent was to disenfranchise native Hawaiians.
I also want to highlight this:
> A lot of the issues with Hawaii and Native Hawaiians can be traced back to the Kingdom times (but not all).
As in, the Kingdom times that started less than a century prior with the unification of the Hawaiian islands? The same era that coincided with the first century of European contact with Hawaiians? Even if the modern problems are directly related to the policies of the Kingdom, saying that its just the Kingdom is like saying that Titanic sank because of low quality metal in the hull, while completely omitting the iceberg.
Mauna Kea is sacred to the world’s scientists too - it’s a perfect observing site; a spectacular volcano; a unique glacial environment; an isolated habitat for plant and animal life; it feels like there ought to be some way to share the gift of this improbable piece of land with the world.
But yes, the way things have been done in the past affect the relationships we can have now.
> Mauna Kea is sacred to the world’s scientists too
This is ugly phrasing given the history. I don’t think scientists use words like “sacred” to describe objective qualities. Its a false equivalence that undermines the real cultural damage.
Not at all. Pursuit of knowledge is sacred with many cultures. “Native Hawaiians” make up about 10% of the population, many of which of which support these kind of projects. They want their kids to live in a world that values knowledge like anyone else. There is always a vocal group that does not want change. And unlike like devastating resource destruction projects like mining, these facilities can be removed, just like the wind turbines so many complain about. Hawaii needs all the non-tourist projects we can get.
They're not monotheist - one god down is hardly enough.
the mountain is the dwelling place of the goddess Poli'ahu, it is associated with the Hawaiian deities Lilinoe and Waiau, and the summit is considered the realm of the gods.
Is this supposed to be a joke? If so it’s not a very good one. How much do you know about Hawaiian beliefs? You seem to assume Hawaiian culture is based on a monotheistic religion but that’s not the only option and certainly not required for a site to be considered culturally sacred.
Ethnonationalism is disgusting, whether it's a European culture or an indigenous one, right?
If the group holding up the development of this telescope was white Christians claiming it would bring about the wrath of God, we would call them backwards, and barbaric, but because it's a non white culture, we wear kid gloves when talking about them.
I'm not sure that "conquered people still agitating as their former group, against their conquerors" qualifies as ethnonationalism. I think there have to be claims of ethnic superiority, deliberate exclusion of other ethnicities and nationalities, etc etc
In other words, a group of people whose internationally-recognised sovereignty was taken from them under threat of arms is not engaging in ethnonationalism by demanding that some portion of that sovereignty be restored. That's not the part of Nazi Germany that people object to, either.
The Thirty-Meter Telescope is absolutely progress over the superstitions of a defunct agrarian society.
In my opinion, cultures that pursue deeper learning and understanding of the physical world are superior to those which do not. I think perspectives other than this are harmful to humanity.
“Culture” should not be a veto over human progress and the ability to have your superstitions respected by others or even your culture survive is not a human right.
Whether or not a telescope is progress in general is debatable, but let's dig into "defunct agrarian society"
The Hawaiian Kingdom fell to a coup, because some white guy thought that the native Hawaiians were too primitive to govern themselves, and that that was why he and his friends were not allowed to setup sugar plantations on the scale they wanted to, and to own the land outright. The story of the US annexing Hawaii is unambiguously the story of a colonizer telling the indigenous people that their priorities (whatever they are) are childish or superstitions or what have you. And when the indigenous people didn't immediately acquiesce to the colonizer's (patronizing) demands, the colonizer resorted to violence. The queen makes it explicit in her document of surrender that the only reason she is doing so is because of the explicit threats of violence made by (all white) insurgents and the US Navy.
There's some implied sexism thrown in for good measure, although it's not clear to what extent it mattered that the white insurgents overthrew a queen and not a king.
Dismissing, I dunno, the Sarmations as a "defunct society" is one thing. Whatever society destroyed them is almost certainly destroyed themselves. But there are people alive today whose grandparents remember living in the independent Kingdom of Hawaii. The conquerer of Hawaii is very much still alive and kicking.
> The conquerer of Hawaii is very much still alive and kicking.
This all happened in 1898 or something, didn't it?
And Hawaiian Kingdom was itself not even 100 years old at the time, itself being the product of a (native) military conqueror who took over the Hawaiian islands and displaced whatever local societies there were.
I just reject the premise that colonialism was bad and that we are automatically obligated to preserve, respect or maintain these ancient cultures just because they...existed?
Modern democratic societies are healthier, wealthier, safer, more just, and more equal than the societies they replaced. We shouldn't restrain our progress because old superstitions mean someone doesn't want us building scientific instruments on top of some dirt. This is a value judgement and I'm not afraid to make it.
I want to be clear here: there's a difference between colonization and just immigration. Colonialism is the deliberate practice of suppressing, supplanting, and ultimately eradicating the culture of the people living in an area that another culture immigrates to. Its pretty rare for the colonizer to see what they're doing as bad; typically they think the displaced culture is too primitive to do "what's best", and the colonizer is only acting in the displaced's best interests. That those best interests lead to massive profits for the colonizer and the total dissolution of the displaced, millenia-old culture rarely causes any cognitive dissonance in the colonizer.
Obviously I feel pretty strongly about this. But I don't know how to convince you that colonialism is bad. But on the off-chance you're willing to be convinced, read on.
The unification of Hawaii was a military conquest by the natives from one Hawaiian island onto the other Hawaiian islands. Those islands were settled by Polynesians about 1000 years previously, and the culture was pretty uniform, even as it was a collection of kingdoms. This is less "Norway conquers England" and more "unification of England".
Moreover, the unification of Hawaii happened 17 years after first contact with Europeans, and the kingdom era basically coincided with the era of whalers, foreign plantations, and foreign immigration. Which makes the "unification of England" metaphor more apt, when you consider the role Scandinavian immigrants/colonists played in the unification of England.
To be super clear, the issue with colonization has never EVER been "we should let less advanced cultures develop at their own rate". The issue is that whatever development occurs does not happen in collaboration with the "less advanced" culture. Its always "I have guns, so therefore I have superior moral knowledge in all things". Its barring natives from voting, because they don't own enough property, when the concept of property ownership is less than a century old in the "less advanced" culture (and was forced on them by the "more advanced" culture). Its forcibly removing children from their families and even barring them from speaking the language of their parents [0].
> But the more I learn about this, the more the Mauna Kea telescopes feel an awful lot like Mt. Rushmore: colonists moving in and saying that the natives' claim to a place is less legitimate than whatever "progress" the colonists have planned.
I'm sorry but this is completely not true.
Firstly, Maunakea never belonged to the Native Hawaiian people as a whole. It really belonged to the monarchy. Mass access to the mountain didn't really happen until the astronomers put in the access road.
Secondly, there are no "colonists" like there were on the mainland. People did not come in and forcibly remove people. Immigration from all over happened during the monarchy and was even encouraged by it due to the needs of the plantations.
Thirdly, no one is saying the claims of the Native Hawaiians that are protesting the telescope are less legitimate. Great care was taken to make sure community concerns were addressed and that the TMT is not actually on the summit or near and spots that are broadly and historically considered sacred [1] (interesting fact, Liluokalani's book doesn't mention Maunakea, and mentions only Mauna Loa as really sacred; Native Hawaiian historian David Malo mentions it, but only is passing as an adze quarry).
Reference 1 are the findings of the hearing officer representing the Board of Land and Natural Resources regarding the permit to build (CDUP), which was subsequently upheld by the Hawaii Supreme Court [2].
I think the difference is that Mauna Kea is uniquely suited for an observatory and happens to also be sacred. I’m not surprised a place with such clear views of the stars is sacred. Mt. Rushmore is different. There’s nothing that makes the Black Hills uniquely suited for a tacky sculpture. It was constructed out of spite and the site was chosen to prove a point.
You're not wrong re:Rushmore, but I think you overly privilege the perspective of the scientists who are displacing the native Hawaiians. From the native perspective, there's less difference between "monument to the greatness of the white colonizer" and "huge set of instruments that are used almost exclusively by transients that don't really contribute to the native community". The problem isn't the intent of the builders (there's a decent argument that spite and dominance were not on the agenda for Rushmore), it's that that nobody considered the people being displaced.
Also, Mauna Kea is arguably unique in US territory for seeing conditions, but it's by no means unique in the world. A lot of the same people I worked with who had collected data at Mauna Kea also did so at Cerro Tololo and other telescopes in the Atacama desert. But it's definitely unique to the Hawaiians. In that sense, it and Rushmore are very similar.
> I can’t help feeling like the Arecibo case should be a lesson for the TMT movement: you’d miss the telescopes if they went away.
Generally when people are fighting for their sovereignty I don't presume to know what is best for them. That's kind of the whole point of fighting for one's sovereignty.
This isn't confusing. It's totally rational to not want limited, unspoiled land to stay that way on the one hand, and then on the other hand having lost that battle it's fair to prefer a working telescope over the wreck that's at Arecibo now. It's not an obvious conclusion from those two perspectives that one would therefore prefer to have a pristine environment spoiled with concrete.
There are 13 telescopes on Mauna Kea already - and some are already due to be decommissioned. It’s not unspoiled and pristine. If they don’t continue to develop the site, the telescopes there will fall into obsolescence, and ultimately disuse. Pushing back against continued development on the site is, ultimately, pushing for it to go the way of Arecibo.
Or they could perform an explicit reclamation project, to try to restore the land as best they could to the way it was prior to 1893.
There are more options than just "build more telescopes" or "let the existing telescopes rot". Of course, just letting them rot would be playing to the standard colonial practice of extracting value, then leaving consequences of that extractive effort to the remaining indigenous people.
This is simplifying the issue too much. Mauna Kea is the most sacred mountain in Hawaiian culture, Arecibo wasn't built in particularly special land as far as I know.
Arecibo is really awkwardly placed for being anything but what it was. It’s at the end of a long windy narrow road up the side of a mountain in the jungle. And when you get there, there’s just about enough room for a little building perched on the side of a pit.
They can fit a lot of biology and computer science schools at the base of that road, I bet.
Its location in a remote area made it good for what it was, a telescope with relatively little surrounding radio interference, but it really isn’t suited for other uses that bring in more people.
It’s unfortunate since there’s a lot of pride about what it used to be on the island, but I feel like this is more of an emotional grasp than something that actually requires that site.
There has also been more and more radio interference at that site over time. It isn't that remote. Sites that are really out in the middle of nowhere in empty desert, like the VLA in New Mexico and MeerKAT in South Africa, have far less radio interference.
It really wasn’t meant to be in a totally radio silent area, but that just happened to be another advantage. The main point was the bowl-shaped area which is somewhat unique. You don’t need that kind of geology just for an educational center.
Having made the trek myself, and seeing one, in my opinion, of the great wonders of the modern world… I can certify that i would not drive there to just experience science museum stuff. Driving in puerto rico is terrifying, and up that hill to Aribaco… never again.
Yep. Parking for visitors (and staff) was an absolute nightmare the entire time I worked there. I can only imagine how much worse it'll be if the revamp the visitor center.
There's almost no space on-site for more parking without tearing up more of the natural environment. Though perhaps without the need to maintain the superstructure any more they could repurpose the Physical Maintenance yards into more parking.
Wasn't a priority. It was an active scientific facility, so the priority was on producing science. The site was chosen for being remote and shielded from the outside by hills/mountains, so it really is a long winding road to the entrance gate.
I can't really think of a suitable site for parking within say 10min of the site, so it'd be a long shuttle ride.
When I visited Arecibo (which I highly recommend but the way - one of the coolest things I’ve ever seen), the intern giving me a tour told me that Arecibo was essentially the main way we had to detect asteroids that might hit earth. Without it, we may not have enough time to launch an asteroid redirect mission.
If that’s accurate, it seems penny wise and pound foolish to have spent ~$300 million on the DART test but then not spend the extra ~$50 million needed to actually detect an asteroid coming towards us.
Are you sure? I recall that the dish was spherical, not parabolic, and had a movable receiver mounted on cables; moving the receiver adjusts the direction from which signals can be received. Indeed, Wikipedia claims that it was steerable [0].
You're kinda both right; the dish itself was fixed, but the system as a whole still had limited steerability because it was (spherical?) instead of parabolic, allowing 20° of the zenith.
The competition for giant Arecibo-like telescopes is arrays, and since their cross section goes to zero as you turn them towards the horizon (straight up and they're spaced out, from the horizon they're in a line), they are limited within some reasonable range of the zenith as well.
Most of the large (more than a few hundred meters) potentially hazardous asteroids are thought to have been found. However, there are some locations (relative to Earth's orbit) that are difficult to view from the ground, because you can only observe them at twilight. The best way to find those last remaining potentially hazardous asteroids would be to launch a space telescope to the Earth-Sun Lagrange Point 1.
In the grand scheme of things, this type of mission wouldn't cost that much, but so far, nobody has made the decision that making sure Earth doesn't get hit by an asteroid is worth an investment of a few hundred million dollars.
And yet, a straightforward mission that would identify all remaining potentially hazardous asteroids hasn't gone forward. DART is great, but it's useless if you don't see the asteroid coming long in advance.
In the grand scheme of things, this type of mission wouldn't cost that much, but so far, nobody has made the decision that making sure Earth doesn't get hit by an asteroid is worth an investment of a few hundred million dollars.
Late last year, NASA approved development of NEO Surveyor, an infrared telescope that will search for near-Earth objects from Sun-Earth L1. NASA estimates that it will launch in 2028 and cost $1.2 billion.
It seems that Starship well greatly upend these calculations and considerations. When launching 100 tons of payload costs $10 million, we should start seeing a lot more science being launched.
When I visited Arecibo [...], the intern giving me a tour told me that Arecibo was essentially the main way we had to detect asteroids that might hit earth.
Arecibo wasn't used for detecting asteroids—it was used to characterize asteroids that were detected by other means. Arecibo observed asteroids via radar. The power necessary for a radar observation goes up very quickly with distance to the target (proportional to distance to the fourth power), so radar would generally be a poor choice for hunting for asteroids.
The problem is most people with $300 million aren't willing to spend it on this. They're more worried about how to get another $300 million. That mentality how they turned $150 million into $300 million in the first place.
Government spending on the other hand, is mostly decided by poor people (majority of voters) who are more worried about tomorrow than 1000 years from now.
> Government spending on the other hand, is mostly decided by poor people (majority of voters)
Government spending is decided by Congress and the President, who are not poor people. There is a convoluted selection process in which rich people (donors) select the pool of candidates from a group of rich people, and then they let poor people vote on which of the rich people selected by other rich people they would like to have make decisions for us.
On a practical matter it is clear poor people do not make decisions because poor people want things like universal health coverage, but we do not have that.
> Government spending on the other hand, is mostly decided by poor people (majority of voters)
Government spending is mostly decided by huge corporations, firstly the arms industry. If poor people controlled our budget we wouldn't have throngs of homeless people in every city in the country.
> Government spending on the other hand, is mostly decided by poor people (majority of voters) who are more worried about tomorrow than 1000 years from now.
I’m fairly sure studies of voter sentiment & positions vs. legislative activities and executive priorities do not back up this guess.
Yeah, I am sure poor people prefer to give dozens of billions every year to Lockheed Martin, Boeing, Northrop, General Dynamics, BAE et caterva instead of affordable public housing and public health.
I see the homeless living on their tents, the inner city blacks and the white unemployable rednecks gnashing their teeth in unison: "Don't you dare buy a single F-35 less to give us some fucking stinking doctors!"
uhh, I am scratching my head at this. You do realize an "asteroid redirect mission" is science fiction right? Not something we actually have the capability to do.
You mean aside from the DART (Double Asteroid Redirection Test) mission already launched, tested, and deemed a success?
As a part of NASA’s overall planetary defense strategy, DART’s impact with the asteroid Dimorphos demonstrates a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet, if one were discovered.
Sure, it's not like we have a fleet of Asteroid Redirection modules lined up ready to go .. but it is an actual capability we have and something we have already done.
This altered the orbit of one asteroid around another. It's moot. You have to either eliminate the asteroid (good luck) or alter it's orbit around the sun (those delta-V numbers just got huge) to be meaningful.
Suggesting we have an "actual capability" is just conjecture. It's a NASA project. According to them, the Space Shuttle was a successful program.
Do these massive telescopes have a future, when we could just build smaller ones and use aperture synthesis to pretend like we have a really really big telescope?
For receive only, yes, aperture synthesis (like the VLA and the GVLBI) is capable of resolving more precisely than even Arecibo could. But Arecibo also did a bunch of active radar mapping of things within the solar system, which aperture synthesis cannot replace. You can't solve the coherent beam problem without actually having an antenna that really is that big.
> The thinned-array curse (sometimes, sparse-array curse) is a theorem in electromagnetic theory of antennas. It states that a transmitting antenna which is synthesized from a coherent phased array of smaller antenna apertures that are spaced apart will have a smaller minimum beam spot size, but the amount of power that is beamed into this main lobe is reduced by an exactly proportional amount, so that the total power density in the beam is constant
So you can transmit with a sparse array, but the power you can deliver with it (for a set synthetic aperture size) decreases with the degree of sparseness. No free lunch.
You know how Nyquist says you must sample at minimum twice your highest "frequency" or your get aliasing in your spectrum? It's the same with antennas except you must sample at least 1/2 your wavelength or you get grating lobes (the equivalent of aliasing) in you far field pattern; it's all the same math. A sample in time is equivalent to an antenna element sampling space. A big reflector is equivalent to sampling everything at once with no gaps; it's bandwidth independent. You can only put array element so close together, limited by the size of the element (itself is limited to a fraction of the lowest wavelength), electronics, and unwanted inter-element coupling (though there are tricks to take advantage of this coupling and make very wideband arrays).
If you leave "gaps" in your array elements, that's not a problem receiving strong, periodic signals. You can physically move the elements to fill in the gaps to remove those lobes; the equivalent of an equivalent time oscilloscope or a synthetic aperture radar. The problem is you can't do that when transmitting since you only have one opportunity to send something (non-periodic).
There are other disadvantages with phased arrays. Each amplifier has to be matched in amplitude and phase. I've had to bin lots of amplifiers as some have phase compression and some phase expansion over amplitude. That distorts the pattern over the pulse.
On the receive side, each receiver has thermal noise un-correlated with the others. So for N antenna elements, you received signal-to-noise scale proportional to sqrt(N) instead of N like you have on transmit, or with a big reflector. This is why arrays suck for very weak signals. Notice NASA keeps building big dishes for their DSN instead of "cheaper" arrays.
Then there's the whole timing and phase noise issue with distributing an oscillator.
Tough you can only make a reflector with about 100 dB gain.
massive telescopes still win in terms of light sensitivity per dollar. apature synthesis/VLBI are the clear way to go for angular resolution but for bigger fainter objects, you care more about area where a big dish does better.
It had a powerful transmitter for radar work, and there are advantages to having a single, giant aperture when it comes to maintaining low sidelobes, power amplifier coherency, etc.
Looking at the photos, the dish itself looks relatively thin. With modern composite materials, I bet it could be rebuilt much lighter than before and not need such substantial support. Still, it would need to be paid for so....
Oh goodness... I didn't expect to shed a tear at the end of that. What a gorgeous bit of writing. I can only aspire to be such a powerful storyteller as Mr. Chiang. Thanks for sharing.
Great news, but I'm still sad due to the lack of interest in funding a replacement. To put it in perspective, the cost of just one football (Premier League or NFL) stadium would pay for an entire radio array.
I am reminded of a 1973 story by Frederick Pohl called "In The Problem Pit" ( https://www.rulit.me/books/in-the-problem-pit-read-682068-1.... ). In the story the Arecibo telescope itself had been abandoned and it took place in a network of natural caves underneath it, a silo of sorts where people gathered in a 'think tank'.
"And then, when all radio telescopy was driven to the far side of the Moon by a thousand too many radio-dispatched taxicabs and a million too many radar ovens, the observatory no longer served a function and was abandoned."
The events in the tale take place in ~2048 and Pohl imagined that even at that future date the rusted cables were still holding the catwalk aloft. He did not live to see the facility's collapse.
> Arecibo’s prowess at astronomy was a source of pride in Puerto Rico, and many have been disappointed with the NSF’s decisions.
Such a contrasting view compared to the long fight in Hawaii over the Thirty Meter Telescope project [1], where locals have continually fought and protested. It’s tied up in the Hawaiian sovereignty movement, and a lot of cultural connotations, but I can’t help feeling like the Arecibo case should be a lesson for the TMT movement: you’d miss the telescopes if they went away.
[1] https://www.npr.org/2022/07/31/1114314076/hawaii-mauna-kea-t...