The Astronomy Thread

Cybsled said:

Confirmed separate evolution of life outside of Earth would be THE most monumental discovery in human history for starters

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Fixed that for you.

It would be significant if additional proof of life were discovered in our own solar system because that would suggest that life is much more common than we currently assume. The sheer size of our galaxy/universe makes the existence of other lifeforms essentially a given.

And that would mean we. are. fucked.

It would mean that we're NOT the first species to survive past the Great Filter, we're just the next doomed one up to bat.

khorum said:

And that would mean we. are. fucked.

It would mean that we're NOT the first species to survive past the Great Filter, we're just the next doomed one up to bat.

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The Great Filter theory does not assume that the improbable step is in the future, we could have already gone past the point at which most life is assumed to fail.

Or it's just possible that certain things that sci-fi takes for granted aren't actually possible. If FTL travel is impossible then it's entirely possible that there could be an interstellar civilization in the same galaxy as us that will never encounter us because the galaxy is just too large. If advanced methods of terraforming never materialize than the growth of an interstellar civilization would be incredibly slow, especially one that can only travel at sublight. etc etc

Gavinmad said:

The Great Filter theory does not assume that the improbable step is in the future, we could have already gone past the point at which most life is assumed to fail.

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It doesn't assume that at all, that's just the OBSERVED STATE of the universe given everything we've observed. And so long as we don't see any evidence of alien life, the presumption that we are the first to survive the Great Filter will be the default presumption. It originated as a response to the Fermi paradox, which asks how we cannot observe any evidence of Dyson Swarms or Kardashev-3 type galaxies if the Drake equation's proposition is reasonable.

Once we DO observe any evidence of multicellular life on another planet then our likelihood of advancing beyond a single-planetary civilization becomes orders of magnitude smaller.

khorum said:

It originated as a response to the Fermi paradox, which asks how we cannot observe any evidence of Dyson Swarms or Kardashev-3 type galaxies if the Drake equation's proposition is reasonable.

Once we DO observe any evidence of multicellular life on another planet then our likelihood of advancing beyond a single-planetary civilization becomes orders of magnitude smaller.

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Except we don't know how reasonable the Drake equation is, or whether the Fermi "paradox" really has to be a paradox. There could be many reasons why alien civilizations would not want to be seen or haven't been. You seem pretty sure that we'd be fucked due to some theories based on our current knowledge of the universe when our knowledge still has huge holes.

A universe where we're "not fucked" as you put it, but where we're alone and Earth is the only place that life sprang up at all, would be unthinkably improbable (and pretty boring as well I might add). My personal conclusions from that scenario would be either:

-The universe is a simulation and Earth was picked as the starting point to play out this expansion of life from a single point. Sid Meier's Civilization+Alpha Centauri+++ on some unthinkably powerful Quantum type computers if you would.

or

-There really is a god.

They don't have to be mutually exclusive I guess. A guy playing the above game with world builder powers would be pretty omnipotent as far as we're concerned.

You're hoping we somehow won the lottery with the most absurd odds you could ever imagine as the only life in the universe.

Gavinmad said:

The Great Filter theory does not assume that the improbable step is in the future, we could have already gone past the point at which most life is assumed to fail.

Or it's just possible that certain things that sci-fi takes for granted aren't actually possible. If FTL travel is impossible then it's entirely possible that there could be an interstellar civilization in the same galaxy as us that will never encounter us because the galaxy is just too large. If advanced methods of terraforming never materialize than the growth of an interstellar civilization would be incredibly slow, especially one that can only travel at sublight. etc etc

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Hasn't the entire thought of terraforming been debunked already? Even if we devise a method to process and output a molecule needed for a stable atmosphere we still need an entire moon or planet's worth of the raw materials. So it's still limited to a world that already has the materials in an already habitable zone and there's usually a very definitive reason why the thing isn't already livable.

The great filter strikes me as idiotic to be honest. It’s like a guy living in a hut on a deserted island assuming that all other huts in the ocean failed because he hasn’t seen any evidence of huts besides his own yet while he is awake.

All we really have is what, radio signals as a basis? We’ve had that for 100 years and the ability to detect faint stuff a fraction of that time. The probability that a distinct signal would cross Earth’s path at the exact same time we had the technology also AND were listening is tiny.

Great Filter is confusing lack of evidence AS evidence.

Cybsled said:

The great filter strikes me as idiotic to be honest. It’s like a guy living in a hut on a deserted island assuming that all other huts in the ocean failed because he hasn’t seen any evidence of huts besides his own yet while he is awake.

All we really have is what, radio signals as a basis? We’ve had that for 100 years and the ability to detect faint stuff a fraction of that time. The probability that a distinct signal would cross Earth’s path at the exact same time we had the technology also AND were listening is tiny.

Great Filter is confusing lack of evidence AS evidence.

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You're a fucking retard.

Pharazon2 said:

Except we don't know how reasonable the Drake equation is, or whether the Fermi "paradox" really has to be a paradox. There could be many reasons why alien civilizations would not want to be seen or haven't been. You seem pretty sure that we'd be fucked due to some theories based on our current knowledge of the universe when our knowledge still has huge holes.

A universe where we're "not fucked" as you put it, but where we're alone and Earth is the only place that life sprang up at all, would be unthinkably improbable (and pretty boring as well I might add). My personal conclusions from that scenario would be either:

-The universe is a simulation and Earth was picked as the starting point to play out this expansion of life from a single point. Sid Meier's Civilization+Alpha Centauri+++ on some unthinkably powerful Quantum type computers if you would.

or

-There really is a god.

They don't have to be mutually exclusive I guess. A guy playing the above game with world builder powers would be pretty omnipotent as far as we're concerned.

You're hoping we somehow won the lottery with the most absurd odds you could ever imagine as the only life in the universe.

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What could possiby be unreasonabe about the Drake Equation? It's about as straightforward as you could get:



That's all it is. Considering the rates of stellar formation, the ratio of stars in their main sequence, the ratio of those main sequence stars which would have rocky planets in the habitable zone etc. the number radio-transmitting civilizations in the Milky Way galaxy could be anywhere from 1000 to 100 million. For N to equal one, the observable universe would have to be radically different than what we have observed so far.

Given that, Enrico Fermi posited that since the Drake Equation shows the likelihood alien civilizations to be extremely high, how come we haven't listened artificial radio transmissions or Dyson swarms or chemical contrails or __ANY__ sign of these alien civilizations. That's all the Fermi Paradox purports to be.

The simulation hypothesis and other anthropic arguments are more or less CANDIDATES for the Great Filter anyway, and one that would fit reasonably well.

khorum said:

Given that, Enrico Fermi posited that since the Drake Equation shows the likelihood alien civilizations to be extremely high, how come we haven't listened artificial radio transmissions or Dyson swarms or chemical contrails or __ANY__ sign of these alien civilizations. That's all the Fermi Paradox purports to be.

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Because the whole basis is human centric and makes assumptions.

To start:
1) the civilization invented radio and broadcast it for an extended period of time, with said broadcast intersecting with Earth at some point
2) the civilization invested heavily in some manner of technology on a literal astronomical scale

#2 makes a -lot- of assumptions that such a structure would even be practical for a civilization advanced enough to make one.

So the bar is low with #1. Now we have to factor in:
1) did the signals cross our planet?
2) if they did, was it during the 50 some odd years we were actually looking?
3) did the civilization move past radio by the time such signals would cross our path?
4) were the signals coherent enough to be recognized as signals vs background radiation/cosmic noise on the chance we were looking?

The whole basis of fermi/great filter is based on the fact that during the 13 billionish history of the universe, in the span of approximately 50 years, with our limited technology, we couldn’t find anything. That is the cosmic timescale equivalent of saying you’ll look for a hidden object, scan the room in a fraction of a second, then conclude the object doesn’t exist because you didn’t see it

pharmakos said:

I wonder how the soil ended up with so much perchlorate, seems really weird

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No idea. They kinda added two and two fairly recently---recently enough that the author of The Martian wasn't able to put it into his book. Both Spirit/Sojourner found them and finally Opportunity has found it everywhere so the thinking is that it's everywhere in those insane concentrations.

Even without the perchlorate problem a Martian base would have to be underground beneath tons of regolith to mitigate long term radiation exposure, which would likewise compromise agriculture and cause cancers, that's because Marss core is dead and doesn't rotate so it doesn't generate the sort of magnetosphere that shielded terrestrial evolution from cosmic radiation.

But between the costs of radiation shielding and managing the perchlorates (either through high-powered UV or heavy water curing) it's the perchlorates that will inevitably keep incurring chronic maintenance and labor expenditures long after the radiation shielding has become a sunk cost.

LachiusTZ said:

Its a fucking death world.

You would have to, essentially, build a completely self contained habitat. Then the dust would fuck you.

Its just a more complicated, harder, farther away, more expensive, Moon base. There is no real benefit. Its harder to inhabit, and mine than asteroids.

Its a shiny object for stupids.

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Well if the costs came down enough it would be worthwhile for tourism and stuff. But otherwise yeah.

Even putting a simple radio telescope observatory on the far side of the moon, where it's tidally locked away from terrestrial noise and has no atmosphere, is already more practical and beneficial than any presumed Mars colony.

Moon doesn’t have the perc problem, but dust is still an issue they have to solve for. It is ultra fine and gets stuck in the lungs as a result. Apollo astronauts had some issues from short term exposure, prolonged would risk serious respiratory issues unless they could prevent prolonged exposure in the air.

Perc can at least be used to help make oxygen and rocket fuel.