Space Thread

[01101010]

Crazy to think that some of those really faint lights you can see in other telescopes are actually full galaxies. And those hubble/webb comparisons are fantastic. Webb does provide a lot more lens flare - and give credit to Hubble, it still stands up relatively well... wonder if they'll reproduce all the Hubble finds with Webb eventually.

[Samwise]

Which might just mean we have learn to think more broadly about possible signals and signs. Including something like the Webb or a future instrument being able to see clear signs of industrial or post-industrial technological output at a planetary scale.

Yeah, if we pick up any evidence of intelligent life I think this is going to be what it looks like, not an intentional signal.

I tend to think the L in the Drake equation is a pretty small number, though, which makes it a hell of a needle in a haystack.  If a star has a lifetime of 10 billion years, and it has detectable intelligent life orbiting it for less than a thousand of those years, then you have to sift through more than 10 million habitable-looking stars to find one that happens to have an industrial civilization at the time you're looking at it, even if you assume that all such stars will inevitably give rise to intelligent life at some point.  When you factor in all the things that have to go right for a particular planet to be hospitable to complex life (the theory that Earth is special not only because it's in the goldilocks zone relative to the sun but also because of the Earth/moon system that was formed by a chance collision at just the right spot and angle), the odds only get a lot worse. 

Given the sheer size of the universe it's probably out there somewhere but we're unlikely to stumble across it (or vice versa).

[slog]

Which might just mean we have learn to think more broadly about possible signals and signs. Including something like the Webb or a future instrument being able to see clear signs of industrial or post-industrial technological output at a planetary scale.

Yeah, if we pick up any evidence of intelligent life I think this is going to be what it looks like, not an intentional signal.

I tend to think the L in the Drake equation is a pretty small number, though, which makes it a hell of a needle in a haystack.  If a star has a lifetime of 10 billion years, and it has detectable intelligent life orbiting it for less than a thousand of those years, then you have to sift through more than 10 million habitable-looking stars to find one that happens to have an industrial civilization at the time you're looking at it, even if you assume that all such stars will inevitably give rise to intelligent life at some point.  When you factor in all the things that have to go right for a particular planet to be hospitable to complex life (the theory that Earth is special not only because it's in the goldilocks zone relative to the sun but also because of the Earth/moon system that was formed by a chance collision at just the right spot and angle), the odds only get a lot worse. 

Given the sheer size of the universe it's probably out there somewhere but we're unlikely to stumble across it (or vice versa).

Even we could stumble upon it,  it's highly unlikely would could make any kind of contact without some way to travel faster than light.  Sending out a "hello" signal might take 5 million years to reach them.

[Samwise]

Yeah -- the number of stars that are close enough for reasonable two-way communication (i.e. exchanging messages with a latency that's shorter than a human lifetime) is only in the hundreds.  Getting a one-way message from a distant long-dead civilization would be pretty rad, but I guess if it needed to be focused in order to cross that distance, there's no reason it'd be pointed at us since our star might not have even existed at the time they sent the message.

[Chimpy]

Man it totally sucks that the cool pictures from Webb have drowned out the news of the even cooler video of Musk's "starship" rocket having an engine explosion when they weren't even planning on igniting the engines at 4:20 PM local time yesterday. 

[Samwise]

That was real?  I thought it was a viral marketing campaign for Kerbal Space Program 2.

[MahrinSkel]

Maybe we shouldn't be trying to find aliens.

I'm just saying, given our track record, if I was an alien that discovered Humans, I'd probably put a near-c kinetic missile in our face, immediately.

--Dave

[Samwise]

Maybe we shouldn't be trying to find aliens.

Dumb IMO because it assumes that destroying an alien world at a distance is trivial and costless (it's hard enough to even send a radio signal, you think sending a death fleet is gonna be that easy?), and also that there's no potential benefit to be gained from cooperation.  Our own evolutionary and societal history is pretty compelling evidence that "every man for himself" is an evolutionary dead end even if it plays out favorably in an unimaginative game theory scenario.

[Chimpy]

That was real?  I thought it was a viral marketing campaign for Kerbal Space Program 2.

https://arstechnica.com/science/2022/07/spacex-starts-testing-its-super-heavy-booster-and-its-not-good/

[slog]

Maybe we shouldn't be trying to find aliens.

Dumb IMO because it assumes that destroying an alien world at a distance is trivial and costless (it's hard enough to even send a radio signal, you think sending a death fleet is gonna be that easy?), and also that there's no potential benefit to be gained from cooperation.  Our own evolutionary and societal history is pretty compelling evidence that "every man for himself" is an evolutionary dead end even if it plays out favorably in an unimaginative game theory scenario.

I am picturing a fleet showing up in 2 million years to an empty planet and flying back disappointed.

[Sky]

Maybe we shouldn't be trying to find aliens.

Dumb IMO because it assumes that destroying an alien world at a distance is trivial and costless (it's hard enough to even send a radio signal, you think sending a death fleet is gonna be that easy?), and also that there's no potential benefit to be gained from cooperation.  Our own evolutionary and societal history is pretty compelling evidence that "every man for himself" is an evolutionary dead end even if it plays out favorably in an unimaginative game theory scenario.

It would likely be more like putting down a den of rabid dogs than opting out of cooperating with a functioning species.

And if power/travel were for some reason still a functionally limited resource, it would obviously be an impact kinda situation, just use cheap thrusters to nudge a couple planetoids in out direction and it's game over.

[Samwise]

And if power/travel were for some reason still a functionally limited resource, it would obviously be an impact kinda situation, just use cheap thrusters to nudge a couple planetoids in out direction and it's game over.

By the time they reached us our own sun would have already exploded.  And probably the originating civilizations', too.  Space is very very big.

[Trippy]

Maybe we shouldn't be trying to find aliens.

Dumb IMO because it assumes that destroying an alien world at a distance is trivial and costless (it's hard enough to even send a radio signal, you think sending a death fleet is gonna be that easy?), and also that there's no potential benefit to be gained from cooperation.  Our own evolutionary and societal history is pretty compelling evidence that "every man for himself" is an evolutionary dead end even if it plays out favorably in an unimaginative game theory scenario.

Even if you assume there might be a benefit in some situations it would be difficult to prove the "good" outweighs the "bad". To put it in sci-fi movie terms for every "Arrival" there's probably a lot more "Independence Day"s out there.

[Samwise]

You can't "prove" anything either way, given all the unknown unknowns which is what makes that analysis dumb.  It takes a bunch of things as givens and then draws conclusions from them; it's classic "begging the question".  The two biggest errors that stand out to me (although I could probably go on for pages) are the assumptions that:

1. the "Destroy" move can only possibly benefit you.  What if you try to destroy them, you fuck up, and then they retaliate, where otherwise they would have left you alone?  Oopsie poopsie, you completely misunderstood the rules of this game and now you're dead!  Remember, one of the premises was that any civilization might be at any arbitrary level of technological sophistication -- you cannot therefore safely assume that any attempt at destruction won't be thwarted by superior technology on the receiving end.
2. the "Contact" move can never possibly benefit you.  What if you make contact and they send you a recipe for cheap graphene because why the fuck not?  Hey look, a benefit.  Maybe you can use all that cheap graphene to swat away the asteroid that the dumbass civilization of psychos blew up their own sun in order to launch at you.

The FAR more likely scenario is that there are neither "Arrivals" nor "Independence Day"s because interstellar travel is wildly impractical under the laws of our universe.  Even "Contact" seems very unlikely to me since we can't even communicate FTL, much less actually move mass FTL.

[Samwise]

The other really big dumb assumption (and this just comes from watching too many movies IMO) is that given the possibility of interstellar travel there'd be any benefit to taking over other worlds.  Stories like War of the Worlds and derivatives like Independence Day are based on extrapolating the cost and benefit of terrestrial conquests to interstellar scenarios, but it doesn't actually make sense because of how fucking big space is relative to the earth.  If you can somehow find enough energy to power a warp engine and move a massive fleet to a distant planet and then bring all its resources back in a reasonable timeframe, odds are you can find enough energy to just build more planets with whatever resources you want, in a more convenient location.

[Khaldun]

Game theoretical modelling usually fails to describe or predict real-world behavior because it is in fact only a model, and usually one that always assumes there can be only one winner in the situation being modelled and that all players are equally deceptive and determined to win. That article pretty much puts it up front: the model only explains anything if the civilizations in question are certain in the same temporal moment that the other exists and that they have the ability to destroy the other civilization and that all civilizations are equally determined to survive and expand. In real contexts, none of those things are likely to be true in the way that the model requires.

TRAPPIST 1 is about 40 light years from our solar system. There are planets in the habitable zone of its star, though that star is very different from our own and so is that solar system. Let's just say that at the same exact moment that we point the Webb at TRAPPIST (next year, in fact!) intelligent, technological beings on one of the TRAPPIST planets is pointing something like the Webb at us, or that they have done so within the last two hundred years or that they will do so within the next two hundred years. First off, that would be so extraordinary a temporal coincidence that it's nearly unimaginable in its own right. But ok, so we both decide at our roughly similar technological moment that there's an intelligent species on that their planet and we gotta kill them before they kill us. Is that because we are determined to survive and expand? I guess so, though you might be forgiven for looking at this political moment in human history and wondering whether we are in fact determined to survive. We're not doing any other rational game-theoretic thing that would validate that assumption, after all.

But ok! Death to the Trappists! So, um, how do we do that, exactly? Right, attach some engines to large asteroids and aim them at their planet! It worked for the Centauri, it'll work for us.

Wait, what's that? We don't have the capability of building large rockets and attaching them to large asteroids and precisely calculating their launch trajectories to get them to where the Trappist planet will be in, um, let's be generous and say it's a still hypothetical rocket that could get a large mass to travel a light year in maybe 10,000 years, so it'll get to Trappist in under half a million years. Let's be extra-generous and say that somehow the guidance and launch systems on this hypothetical rocket are good enough for us to actually hit the target.

Remember! They might be doing the same thing to us! But, um, we can't stop them from doing that until 400,000 years from now, so...If you can see signs of industrial and post-industrial technologies with observational instruments located near the homeworld of an intelligent species, and game-theoretically they all send off the asteroid bombs the moment they see it, then somewhere around 1900, we already have inbound world-destroyers heading for us. If human beings are still around 400,000 years from now, I'd like to think that stopping a bunch of incoming asteroids with rockets on them will be a fairly trivial problem--by that point we'll have to be living at the scale of our solar system, anyway, if we're still an ongoing concern. Same thing for the Trappist folks.

So this pretty much explains nothing. It doesn't explain at all why civilizations might go quiet--we wouldn't know for 400,000 years that someone took a potshot at us. The only time you could nail another intelligent species that evolved within 50 LY of your own planet would be if you pre-emptively fired asteroids at any detection of *life* of any kind, on the grounds that it might evolve to sapience. I mean, maybe that's actually happened to us already a few times, right? Which shows that even that approach might be perverse--all you might be doing is getting rid of the local equivalent of dinosaurs and pushing some other life form towards sapience.

Just think in energetic terms what expending the effort to fuck up Trappists hundreds of thousands of years from now would amount to--it would be the most expensive and complicated global investment of effort and resources in human history to date, for completely uncertain and unknowable ends. I mean, maybe it turns out the atmospheric signs of technology on that Trappist planet would belong to a species that is already operating at the scale of their entire solar system, with large-scale structures and capabilities, who could care less about us until we stupidly fire some rocks at them. Even if you strip it all back to the game-theoretical model, the conclusion makes no sense precisely because it assumes that all parties in the equation are basically on par with each other.

[slog]

Now that we have the alien invasions put to bed, has anyone done the math out on how many possible galaxys that we could see with webb?  In theory, you could do the math out if you figured out how many grains of sand you could hold at arms length.

[Trippy]

NASA stubbornly refuses to specify the number of arc seconds or arc minutes for the images it releases to the public that Hubble and now Webb generate, preferring to use non-math substitutions like "pencil eraser", "pinhead" and now "grain of rice" held at varying distances. This site, however, says that the SMACS 0723 image is "2.4 arc minutes". I'm assuming that's 2.4 square arc minutes. The sphere of the "sky" is 148,510,800 square arc minutes. So the image is about 0.00000001616 of the total sky. I haven't seen an (near) exact count of the number of galaxies "visible" in that image (articles currently say "thousands"). Let's say it's 10,000.

If we assume the universe is homogeneous and isotropic -- aka the "cosmological principle" -- (which it probably isn't even at very large scales) and galaxies aren't blocking other galaxies from view (which they are) that would put the number of galaxies visible to Webb at ~600 billion, assuming it can point in any direction and the planets and Sun have moved in relation to it to not block its view. Which is more than the currently estimated number of galaxies in the universe (~200 billion). So obviously you can't just extrapolate in this fashion.

[pxib]

On the more general subject: Olber's Paradox:

Olbers's paradox, also known as the dark night sky paradox, is an argument in astrophysics and physical cosmology that says that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. In the hypothetical case that the universe is static, homogeneous at a large scale, and populated by an infinite number of stars, any line of sight from Earth must end at the surface of a star and hence the night sky should be completely illuminated and very bright. This contradicts the observed darkness and non-uniformity of the night.

The darkness of the night sky is one of the pieces of evidence for a dynamic universe, such as the Big Bang model. That model explains the observed non-uniformity of brightness by invoking spacetime's expansion, which lengthens the light originating from the Big Bang to microwave levels via a process known as redshift; this microwave radiation background has wavelengths much longer than those of visible light, and so appears dark to the naked eye. Other explanations for the paradox have been offered, but none have wide acceptance in cosmology. Although he was not the first to describe it, the paradox is popularly named after the German astronomer Heinrich Wilhelm Olbers (1758–1840).

[Typhon]

Olber's paradox doesn't understand inflation.

[pxib]

[Count Nerfedalot]

I would REALLY like to see a comparison photo of the same star taken with Hubble. Presumably eventually they will give us some comparison shots but possibly not until May or later when they get all of the instruments aligned properly.

Ask and you shall (eventually) receive:

(Bandwidth intensive):

https://johnedchristensen.github.io/WebbCompare/

Thank you!!!

That is exactly what I wanted.


And looking at the deep field image I see a lot of little dots that don't seem to be stars but you can't tell what they are.  We need a bigger telescope!

[Mandella]

JWST already rocking early universe formation theories.

https://arstechnica.com/science/2022/07/nasas-new-toy-may-have-already-spotted-the-oldest-known-galaxy/

Seems to be a lot more of these galaxies around only a few hundred million years after the presumed Big Bang than predicted. Of course, not peer reviewed early analysis of first data etc etc.

Should be a fun few years (decades) for astrophysicists if this holds up.

[Sky]

Wouldn't it be the youngest known galaxy 

I've always found it weird in archaelogy when they talk about ancient societies, because technically the oldest societies are the ones around us now. Time is weird. Did you guys see the new qbit stuff where they're making time pockets? I want one for an extra few hours of sleep, please.

[Count Nerfedalot]

After billions of years of Sol's inner planets being bombarded by asteroids, on Sept 26, 2022, one of the planets struck back!

https://www.youtube.com/watch?v=bfqVqOl9S9w

https://gizmodo.com/telescopes-capture-dart-asteroid-impact-1849585394

I'm not sure which is more impressive. The bullseye hit on a 170m diameter object 6.8 million miles away at a closing velocity of 14,000 mph, or that we were able to get video of it happening from earth.

[Sky]

Also we had Webb and Hubble aimed at it: https://www.space.com/webb-hubble-observe-dart-didymos-asteroid-crash

[Chimpy]

Big expensive rocket designed by (Senate) committee launched, wheeee.

[Sky]

I'd like to talk to NASA about the launch time *yawn*

[Sky]

Composite of the Pillars 

https://www.esa.int/ESA_Multimedia/Images/2022/12/Pillars_of_Creation_NIRCam_and_MIRI_composite_image

[Trippy]

Last (?) picture from the Mars InSight lander:



Tweet: https://twitter.com/NASAInSight/status/1604955574659035136

Mission page: https://mars.nasa.gov/insight/

[Sky]

It's getting dusty out here, Mr Stark....

[Trippy]

Arise!

https://science.nasa.gov/missions/dragonfly/nasas-dragonfly-rotorcraft-mission-to-saturns-moon-titan-confirmed/

NASA has confirmed its Dragonfly rotorcraft mission to Saturn’s organic-rich moon Titan. The decision allows the mission to progress to completion of final design, followed by the construction and testing of the entire spacecraft and science instruments.

...

With the release of the president’s fiscal year 2025 budget request, Dragonfly is confirmed with a total lifecycle cost of $3.35 billion and a launch date of July 2028. This reflects a cost increase of about two times the proposed cost and a delay of more than two years from when the mission was originally selected in 2019. Following that selection, NASA had to direct the project to replan multiple times due to funding constraints in fiscal years  2020 through 2022. The project incurred additional costs due to the COVID-19 pandemic, supply chain increases, and the results of an in-depth design iteration. To compensate for the delayed arrival at Titan, NASA also provided additional funding for a heavy-lift launch vehicle to shorten the mission’s cruise phase.

[Khaldun]

Starting to get to that point where I wonder how many space probes I will be allowed to see start their mission. This one is only ten years from now, so very good odds. Will be heart-breaking the first time they announce one where I have to say, "I probably won't live to see that one".