This is really high up on my list too. I came in with the same preconception about him that you describe. It was inspiring to see how he changed throughout the book.
I'm really reluctant to talk to strangers, but when I do... I use triangulation, where you don't talk about yourself (a stranger doesn't care) and you don't talk about them (it makes them uncomfortable), but instead you talk about a 3rd subject that maybe is visible to both of you, like the pretty fall leaves.
Actually, last year, right after I learned about triangulation, I was walking my dogs and stranger mentioned the pretty fall leaves to me. I then started telling him that he was using triangulation and explained what it is. He got uncomfortable and walked away. Derp.
This is called small talk, and despite being reviled by many needs, it serves an important social purpose of making people feel comfortable before we talk about things that can get uncomfortable (like each other).
Most people agree that it's silly but needed, which is why when you deconstruct with a random stranger (thereby making it about the two of you and NOT a separate thing), they will feel the need to quickly exit your presence.
Thanks for pointing out mitchellh/nixos-config. Do you have a config published for nixos with UTM? I’m having a heck of a time getting the screen resolution and font sizes where I want them and I’m kind of lost.
Yep. Note that there's nothing you need to do to configure display resolution in UTM / qemu. You do need the spice guest tools installed in your nixos vm though. The only thing you should need to do is set the resolution in whatever display manager you use in nixos. For me, I run the sway window manager. My display manager is kanshi.
Here's a branch that I has some aarch64 specific things in it that I'm using for my guest vm config (I will merge it into the main branch when I get an hour or two so this link might die at some point)
https://git.sr.ht/~averagechris/dotfiles/tree/aarch64-work-v...
Let's say the universe is 14 billion years old and the galaxies in this image are 13 billion years old. The largest the universe could have been at the time is 2 billion light-years across if the universe expanded at the speed of light after the Big Bang. However, if we pointed the Webb in the exact opposite direction we would see galaxies that are 26 billion light years away from those in this image. How is this possible if the galaxy could have only been 2 billion light years across 13 billion years ago?
Also, if the Milky Way galaxy was somewhere within the 2 billion light year diameter sphere of the universe at that time (it wasn't because it isn't that old), the light from this image should have hit us a long time ago.
Get ready for this answer because it is wild: There universe grew way, way faster than the speed of light.
> At this point of the very early universe, the metric that defines distance within space suddenly and very rapidly changed in scale, leaving the early universe at least 10^78 times its previous volume (and possibly much more). This is equivalent to a linear increase of at least 10^26 times in every spatial dimension—equivalent to an object 1 nanometre (10−9 m, about half the width of a molecule of DNA) in length, expanding to one approximately 10.6 light-years (100 trillion kilometres) long in a tiny fraction of a second. This change is known as inflation.
Objects within space can't move faster than light. But space itself can stretch fast enough that they objects within the universe are having the distance between them grow faster than the speed of light.
Not really - inflation ended 300,000 years before galaxies began to form. Galaxies formed at a time when the expansion of the Universe was proceeding much more sedately.
The question was (paraphrasing) why does light from something 2 billion LY away take 12 billion years to arrive? Inflation notwithstanding, I would like to know the answer.
> The largest the universe could have been at the time is 2 billion light-years across if the universe expanded at the speed of light after the Big Bang.
That is the first mistake in your train of thought, the universe doesn't expand "at the speed of light", it is not a ball expanding outwards with an outer shell expanding at a measurable speed.
Instead it expands everywhere all at once, all distances are being stretched. And this streatching doesn't have a "speed" (m/s), there is nothing traveling, so it is not bound by the speed of light. Instead it has a rate of expansion (m/m/s) as in how much each meter will grow in a second.
Sorry, I'm not an expert so I don't know how to explain properly.
In other words, the speed of light is irrelevant. It (or relativity) doesn't dictate at all a limit on the relative speeds of two objects. This much is obvious if you consider two objects moving in oppositive directions at 51% the speed of light. Certainly valid, even though combined their relative speed from each other is >c
You can extrapolate the same to the expansion of the universe, I think, but I may be simplifying too much.
> two objects moving in oppositive directions at 51% the speed of light
> combined their relative speed from each other is >c
We've got to be very precise with the language here. That's not accurate as stated, even though I know what you mean. The relative speed of one of these objects from the other one is not greater than c. You cannot directly add relativistic velocities without making adjustments for time dilation. Adding .51 + .51 to get 1.02 is not how the math works out.
If I am sitting in the middle, observing both objects, then I see the distance between them increasing at greater than the speed of light. But that concept should not be called "relative velocity" of one object with respect to the other. That's different.
No observer can witness an object receding at or above the speed of light. At that point the redshift would completely suppresses the information from arriving.
Not to say there is no such a boundary, it just might not be what intuition would tell us like a baloon, a sphere or similar. Geometry of universe might be a torus, but also not really. Shit gets weird when you start reading research, and it takes a lot of effort to even start reading with comprehension there.
My 'bad' mental model is: In the beginning there was an infinite amount of space and somewhere within that space the Big Bang happened. The universe is all the matter and energy produced by the Big Bang and that universe is expanding at a maximum speed of C through the infinite amount of space.
But you are saying, I think, that before the Big Bang there was no space. The Big Bang produced all the matter, energy, and space itself. And space is expanding, NOT just the matter and energy expanding through the infinite pre-existing space that I imagined.
I still have a very hard time imagining 'no space' before the Big Bang and the concept of space being something besides 'nothing'. Because if space is expanding it must be something more than nothing.
it's not known whether the Big Bang was the beginning of space or time. there's one theory (eternal inflation) that our universe fell out of a continuous Big Bang when a false vacuum collapsed. all the pieces of that field then became particles, since they're high energy compared to the newly-dropped floor of our spacetime.
the kind of expansion happening between galaxies is a different kind of inflation.
it's even more mind-blowing though, because it would imply that the 10^-32 second inflation of our universe from a grain of sand to only 1000x smaller than it is now is just... the steady state, outside our microscopic bubble of observable reality.
The big bang didn't expand from a single point explosion.
The big bang happened literally everywhere in the universe.
The size of the universe both now and at essentially the time of the big bang (or some infinitesimal time after whatever happened at the exact singularity) was infinite.
The energy-density though was much higher, and the universe has stretched so that distant points in the universe were much closer together back then.
The fact that we see galaxies traveling away from us very quickly at high redshift is due to the expansion of space. Those galaxies are going to be stationary on average when measured locally.
It is like you are standing next to someone but you both see each other moving away from you because something is inserting more and more rulers between you.
The insertion of the rulers in that picture is also how the energy density drops over time because there's more and more space between all the stuff, so the density drops, and the temperature drops.
But the big bang happened here 13.7 billion years ago or so, and the big bang also happened 13 billion light years away out there, roughly 700 million years before that light left (ish).
Calling it a "bang" is really the wrong word to use. Its really the big adiabatic cooling where the size of the container just keeps on getting bigger.
And that is probably not the whole picture since there's also inflation in the early Universe to talk about when the Higgs mechanism(s) broke and released a pile of energy and blew the universe up very quickly.
> And that is probably not the whole picture since there's also inflation in the early Universe to talk about when the Higgs mechanism(s) broke and released a pile of energy and blew the universe up very quickly.
1. Is inflation anything more than a "just so" story? That is, is there any evidence besides the overall smoothness of the universe? (Without such evidence, it seems to me that inflation is "the universe is smoother than we expect, so it must have happened this way.)
2. Can you ELI20 why the Higgs broke (I presume you mean symmetry breaking), and why that would release a bunch of energy?
3. The Higgs breaking should release energy in space-time, but inflation was an expansion of space-time. Why should an energy release drive that?
I wrote an undergrad paper on this decades ago now so I'm not sure I can explain that very well any more.
We know the Higgs exists now so electroweak symmetry breaking is on pretty good terms. That means at a high enough energy the W and Z bosons will lose their mass and kind of reverse fuse with the Higgs and photon and you'll get SU(2) Yang-Mills theory. In order to get our universe with broken SU(2)xU(1) symmetry and a massive Higgs and W, Z bosons then you really do need the symmetry breaking mechanism.
I cannot explain why that dumps energy into space-time and why that in particular causes the inflation and expansion of the Universe. I think its dependent upon the exact shape of the Higgs "sombrero" potential and we don't know exactly what that looks like. To have a Higgs mechanism breaking the electroweak symmetry without dumping energy into space time though I think is considered not likely. Once you dump the energy from the Higgs mechanism into space-time I think you're fairly guaranteed to get an inflating universe, but here is where I'm just entirely trusting what I've read in words, with no personal connection to math at all (although I do trust that the math exists for this)
Then on the flip side you can use inflation to explain the large scale mass structure in the universe and the globby strands of matter become quantum fluctuations in the pre-inflation universe. Of course I think they're still off by orders and orders of magnitude between theory and reality still(?) but that does lend some plausibility to it all.
The electroweak symmetry breaking is on much more firm ground since we can point at the Higgs particle and it doesn't make a lot of sense except as a broken symmetry. Since we can produce lots and lots of Higgs particles in the LHC now it means that the plausibility of at least some kind of simple inflationary cosmology is pretty high.
There is a real possibility that there are multiple different regions of the universe (and since the universe is presumably infinite that means presumably infinite numbers of regions) where the Higgs potential broke differently and physics is very different there. We find ourselves in a pretty uniform area of the universe, though, which is probably pretty good, and which is likely also explained by inflation. That might be wrong, but at least it needs to be considered seriously. And someone would need to come up with an explanation of why the infinite Universe would freeze uniformly to having exactly one way of breaking the primordial Yang-Mills symmetry across all of it -- it seems more plausible there would be different regions with fundamentally different electroweak symmetry. We find ourselves in one of the regions conducive to complex life because you need things like stellar nucleosynthesis to have anything interesting to talk about. That is all more of a philosophical story though -- except that we know there was one symmetry breaking and it just seems weirder to have only one and not N.
Well... if the Higgs symmetry breaking did drive inflation, then it happened before inflation. So it may well be the same throughout the universe.
A bit more about why I question the symmetry-breaking driving inflation, though: Let's say that when the symmetry breaks, it releases a lot of energy. Fine. Where does it release the energy? Where certain particles are, or throughout all space? I strongly suspect that it's where the particles are. That leads to those particles having more energy. But inflation isn't an explosion of the matter in the universe; it's an explosion of spacetime itself. Adding a bunch of energy to the matter may make the matter move more energetically; that shouldn't have any effect on the rate of expansion of spacetime.
Open to being proved wrong (preferably in ways I can follow...)
matter is energy and energy is matter. the false vacuum state is where the energy comes from (which is at every point in space-time). even in the universe right now the vacuum expectation value of any field is nonzero since virtual particles are being created and destroyed spontaneously at every point. the false vacuum is similar. when the symmetry is broken that energy is released everywhere.
since energy is matter i assume that means that the energy really is "stored" in a quantum field, so a particle of some sort. the vacuum expectation value of that particle must be large, so that when symmetry is broken those virtual particles decay and create the shower of matter and energy which drives inflation.
iirc, when symmetry breaking occurred, the universe found a new low-energy state, under the floor of the unified field. relative to the new low energy floor, the high energy bits look like particles. so a bunch of particles were produced, each of which had collosal kinetic energy, obeying new physical laws.
If these questions interest you, I’d recommend the book “The End of Everything” by Katie Mack. Ostensibly it’s about the end of the universe but to explain the various possibilities she has to first explain the kind of things you’re talking about.
The Milky Way galaxy really is that old. There are at least millions of stars (red dwarfs) in the Milky Way, probably most with planets, fully that old. Some of those could easily be covered with life nearly that old. And, probably way more black holes that old, many (co-)orbiting those red dwarfs.
That is not to say our galaxy had its present form, then; a bunch of galaxies merged to make ... well, what we are in. (Ownership would be wrong to claim.)
It is really just our own sun that is new. Ish.
That many billions of years is time for a very great deal of evolution. But, also of exposure to such existential risks as nearby supernovas and magnetar starquakes that could sterilize a whole planet down to the mantle. A galaxy is a dangerous place even without alien invasions. So, lots of Pompeiis covering the full spectrum of stages. But given time, life could arise again, wholly new, after.
The universe can expand faster than the speed of light because of the expansion of space. The rule "nothing can go faster than light" is more situational than it's usually presented; I believe the true rule only means that objects that meet each other can't have a speed difference more than lightspeed, but for objects that are far apart, it's possible for them to see the distance between each other grow as if they were moving apart faster than light because of the expansion of space between them.
Yes, because the speed of light relates them. Distance and time are interchangable if you know the speed as well, and especially if you use units where the conversion constant is 1 (ly/y)
Jonathan Coulton started by writing one thing a week. Most of them were meh but there were some that were good. Turns out the important thing is perseverance.
once you have a good development for mechanical aspects you absolutely should record yourself and listen, so you can train your ears for the sound. your own ears will lie to you a lot, and the room/hall acoustics matter. the signal gear for amped instruments matters as well. if you want to play for people you have to train your ears so that you know what good sound, sounds like to most people.
What kind of mill did you get? I've been interested in one but I don't have that much space and I've heard that benchtop mills are not that useful, I hope that's not true since it would be my only option.
I have a lot of space, but check out Blondihacks on YT. They are quite useful, they just have limitations you have to respect. Just depends on what you are trying to do.
(My mill is a Sharp LMV 49 DVS btw). Lathes are a better starting point for most beginners BTW. But really both are fine to start with if in budget.
I worked at a national lab for 5 years and loved it, but I know exactly how you feel about the negative parts. I left and ended up at an ad-tech company and although I didn't like our mission at all, enjoyed the job just because of all the new skills I learned. Eventually I had to leave because I just never could feel good about what we were building.
Then I ended up at my current company. Our mission is to improve supply chains by monitoring vaccines (mostly in Africa at the moment) and perishable goods with our sensor devices. Especially with the vaccines, our mission is literally to save lives. I LOVE it here.
So, the private companies you are looking for are out there, so maybe just stay patient until you find something that you can feel good about.
