The wanting to be unique in the universe is all well and good, but wanting it is not enough to conclude it probably exists.
Finding the biosignatures and detecting abiogenesis may remain difficult. And while I agree life may not exist at the same time, I disagree that the chances are minimal that it does not exist at the same time. It is extremely unlikely that our solar system and situation is unique among the estimated 1,000,000,000,000,000,000,000 stars in the universe.
Especially in light of the existing experimental evidence that the precursors for life can be produced in our universe, even in less than perfect conditions.
I don’t agree that they’re similar. The fact that complex life exists on Earth means we know complex life exists in the universe. Which means we know it’s feasible that it may exist elsewhere in the universe, on some body orbiting one of the sextillion or so other stars we can roughly guess are out there.
there is no similar evidence to indicate any god or space turtles may exist since we’ve observed neither, not on Earth or anywhere else.
Sad fact is we’ve found exactly zero evidence of life elsewhere in the universe either, no matter how much we wish it were so. Maybe we haven’t looked enough yet, or maybe we need to wait a few hundred million years, but so far, all we conclude decisively is that there is exactly one planet that supports life. Wishing is not evidence.
Absence of evidence is not evidence of absence, which is what we have here. One cannot “conclude decisively” on either side.
All of the evidence we have suggests we should expect life if conditions happened as they did for Earth and we have zero evidence that there is anything specifically special about our solar system or planet.
While no clear signs of life have ever been detected, the possibility of extraterrestrial biology is being tested. So far we have found only results that point to life being possible and nothing that would suggest that we are unique at all.
The detection of complex organics coming from Enceladus is an example. Note that even if those organics came from Saturn’s E ring, that is very convincing evidence that the precursors for life are in no way exclusive to Earth.
I agree with this. The argument for life somewhere else is generally that if life occurred once (here), given the visible number of stars and planets, the odd are that life has emerged somewhere else at some time. While I agree the odds are good, like you say, we have yet to find any evidence for it. That doesn’t mean life elsewhere does not exist, tho - I get that. My point is that if we can postulate that life exists somewhere else, so what? What good does it do to state that? We have many pressing problems needing practical solutions right here on our own planet, so why not spend time and energy working on those as opposed to dreaming of space travel and life elsewhere?
Prove it. You can believe whatever you want, but without proof it’s meaningless. And if the Universe was teeming with life wouldn’t some of it have evolved far enough to stop by and say hi by now?
Why ponder it? It raises, at least to me, a fascinating conception of the universe. If stars attract planets, and if the planets that are in the “Goldilocks zone” (Exoplanets | HowStuffWorks) can sustain life, then we are far more mundane as a species than ever fully appreciated.
Granted, these are assumptions. But, I’d argue, they are not especially unreasonable ones. As others have stated, our research has reinforced the notion that our star, and our galaxy, are fairly unremarkable. Couple that with the incredible persistence in life forms to exist where and how they can, and is it really such a stretch to imagine that there are literally billions of planets with life at all stages of evolution and development?
As to why we haven’t met or found them? As I started with in the OP, the Universe is really big. And humanity is rather young. Our outreach to the stars is still counted in decades. We have barely passed beyond our own moon. And perhaps we are in the boonies, universe-wise. Or, more fundamentally, it is not realistic or feasible for large ships to travel dozens, let alone hundreds or thousands, of light years.
It creates a tantalizing prospect of being amongst billions of other developed worlds with no way to contact them. Some may scoff because of a lack of evidence. I’d say that it may be unproven, but that doesn’t mean it can’t be a plausible theory.
Life being common and intelligent life being common are two different things. But even if there were other intelligent beings out there, our dreams about interstellar manned human travel are more about science fiction than practical reality right now.
It is quite possible that if intelligent life did develop that they may just consider the effort not worth it or end up killing themselves before it even becomes practical.
I will bet that exposure to galactic cosmic rays limits human expansion, as even the increase exposure in the South Atlantic Anomaly causes health concerns for astronauts even in low orbits like the ISS.
last I checked, physics works pretty much the same everywhere. if they’re too far away for us to reach, we’re too far away for them to reach. Warp drive, hyperspace, etc. only exist in science fiction, they’re not something “guaranteed” to happen once a civilization advances beyond a certain point.
Single-celled life appears to have developed on Earth almost immediately after it cooled down enough for life to be possible. But it took billions of years from that point before the Eukarotes showed up.
Based on that, the best guess is that simple life forms are ubiquitous in the universe, but complex life forms are orders of magnitude rarer.
But that will remain a guess so long as we have only one data point.
We don’t really need to wait hundreds of millions of years, we should have some fairly conclusive data within just a few decades.
If we find evidence of life on Mars, or on the moons of Jupiter, then case settled, there it is.
If we don’t find any, any at all, that is an interesting data point. Not as definitive, certainly, but it does point towards life being a bit rarer.
I don’t see wishing in this thread, I see speculation based on what little evidence we do have. Wishing implies a desire, speculation simply implies that we don’t know everything yet.
All it takes is for a few of us to escape the bounds of Earth and start settling in space and the future is pretty much set. Just as we expanded to fill every available niche on this planet, we will expand to fill the niches we find in the universe. Unless we manage to kill ourselves off in the next hundred years or less, I think it will be too late, I thin that humanity will be unleashed and uncontainable at that point.
We may very well kill ourselves off before that happens, but that’s a pretty depressing speculation.
As far as “not worth it”, that just ignores that it’s not that hard. Getting into space is hard. Getting infrastructure and construction started in space is hard. Once you’ve done that, though, it gets easier, much, much easier.
If we are mining space materials, and turning those into living space and consumer goods, then where does the effort become not worth it? The time to decide that the effort wasn’t worth it was before the Apollo project. It is simple, we keep growing, keep expanding, and we slowly fill up the solar system. If you have access to even a tiny fraction of the materials and energy of the solar system, getting to another solar system starts being pretty easy. You aren’t taking a ship, you are taking your entire colony of millions of people.
As far as radiation goes, that is only a problem if you envision space stations sitting out in space, rather than being built into the protective shielding of asteroid material. The first is, in fact, a sci-fi idea that will never see real use, and so should not be a consideration when determining the plausibility of a structure.
Given that we don’t know how life originated here on Earth, anyone’s guess is as good as anyone else’s concerning the distribution of life in the Universe outside our solar system.
To clarify, Not finding life on other planets in our solar system will help us narrow where life may be possible, but it will not rule out the possibility it exists.
IMHO the arrogant position is to posit that laws of physics m must be different elsewhere.
To presuppose that nature has an intrinsic structure close to our solar system that does not apply outside our solar system is actually antithetical to the assumptions of Physics. Why our solar system be unique? why add this complexity? If this complexity exists what causes it? Are our assumptions about gravity, mechanics, chemistry and everything else wrong because we are in some portion of the universe where the rules are not uniform?
Yes, we have no evidence for life on other planets, and yes that means we shouldn’t “believe” in them; but it is far more than a guess that life should exist other places in the universe.
We simply expect that the laws of nature apply across the universe and we have zero information to indicate that they do not apply to the rest of the universe at this time.
I don’t think the answer that the general public will accept will come soon though. I mean we have already detected exo-planets with water in their atmosphere and even glycolaldehyde and people generally believe they are alone. As it is very likely that the most complex forms of life we will be at most mats of bacteria I doubt that the desire to meet sci-fi beings will be satisfied.
Heck there is glycolaldehyde in the giant dust clouds in the center of our galaxy. If you have simple sugars with organic structures like HOCH₂-CHO in free space it mostly becomes a lottery prospect about planet formation.
[ul]
[li]Other planets exist: ✓[/li][li]Other planets with water exist: ✓[/li][li]Other planets with water in their atmosphere exist: ✓[/li][li]Other planets with liquid water habitable zones: ✓[/li][li]Other planets with organic chemistry exist: ✓[/li][li]RNA precursors production possible with UV: ✓[/li][li]RNA precursors photostable in UV-rich envronments: ✓[/li][li]Evidence of life on exoplanets: TBD[/li][/ul]
There is just no solid reason to expect that our solar system is anomalous.
The long wait for discovery, or to bin our view that the laws of physics are universal, will allow us to answer other questions.
True, but if we find life under every rock in the solar system, then we can more reasonably conclude that life would be common outside the solar system.
If we scour the solar system, and find no sign of any form of life that did not originate on Earth, then we can lower our expectations.
Finding life that had its own unique abiogenesis would probably teach us quite a bit of how life originated here on Earth, as well.
Wouldn’t this also be consistent with the “Goldilocks zone” I referenced earlier? That is, planets too close to a star are too hot to support life. Planets too far from a star are too cold or gaseous to support life. But a planet that is just the right distance from a star will have the proper potential to develop life.
In other words, the development of life is like a recipe - combine the right ingredients in the correct order under the right conditions and it will develop. So, some stars would not develop planets in this proper zone. But with so many trillions of stars in the universe, there’s going to be a shit-ton (I believe that’s now a recognized unit of measurement) of suitable planets.
Personally, I’m hopeful that simple life will be discovered within our solar system, but I don’t see that we necessarily have to conclude that the “life is common in the universe” hypothesis is discounted just because it’s proven to be unique within our solar system.
Being that I am a deist, you aren’t wrong. My point was that human religions are invariably earth-centric, so theorizing that the universe is teeming with life makes religion seem silly.
Was incredible luck needed for the development of chlorophyll photosynthesis? In which both magnesium and manganese ions play key roles?
And have you ever wondered why chlorophyll, with its almost magical energy-extraction efficiency, rejects green light — the best energy source in sunlight? It might be because, prior to the “invention” of chlorophyll, earth was teeming with halobacteria and other retinal-based life that did extract energy from green light specifically: chlorophyll-based life was making do with the leftover light!
Is magical chlorophyll essential for advanced life? Was its invention remarkable or inevitable? If inevitable, were there are other, even less likely, coincidences needed for advanced life? Could life have transited from ocean to land without the tide pools created by our large moon?
But Drake’s Equation gives us a simple numeric answer:
D = p[sub]1[/sub] • p[sub]2[/sub] • p[sub]3[/sub] • p[sub]4[/sub] • p[sub]5[/sub] • p[sub]6[/sub]
I’ll approximate each p[sub]k[/sub] as 10[sup]3±3[/sup] and guess that there are 6±2 p’s in the product. Is the invention of chlorophyll one of those unlikely p’s? Don’t know. But now that we have Drake’s Equation, simple arithmetic will lead to the exact answer, which is:
• There is a 40% chance we are alone in the universe.
• There is a 10% chance that at least 1, but less than 100,000 other worlds in the observable universe have advanced life.
• There is a 10% chance that more than 100,000 worlds have advanced life but all are outside the Milky Way
• There is a 10% chance that M (the number of planets in the Milky Way with advanced life) is between 2 and 10,000.
• There is a 5% chance that M is between 10,000 and a million.
• There is a 10% chance that M is in the millions.
• There is a 15% chance I should be ashamed of myself for even attempting this estimate.
