100% proof of life on other planets.

originally posted by: Archivalist
a reply to: Soylent Green Is People

Your post is a nice practice in psychological semantics and individual perspectives. I back that guy's viewpoint though. Life is out there, because life is here. Good enough for me. Chicxulub threw some life well out into space.

Earth has been a cesspool of life for a while, I wager that some has left. Doesn't take NASA to put life in space. We've had plenty of meteors and asteroids to get that job done. Besides, if organisms can get high enough to stick to the ISS windows? Any glancing blow of a comet or meteor in our upper atmosphere can pick up hitch hikers.

Extremophiles, tardigrades, dormant spores and seeds, and long hibernation animals like Cicadas or rock toads... Maybe some are hanging around a little further from our backyard than we would imagine.

Meh -- I'm more interested in life that had a totally independent origin than our own life, not life that started on Earth and got thrown into space by an impact event.

If we want to claim that life is a common event in the universe and, consequently, there are also a whole lot of intelligent alien species out there somewhere, one big hint that idea is necessarily true would be to find life of an independent origin in our solar systems (say Enceladus, Titan, or Europa).


Life independently arising in to places in the same solar system would strongly suggest (very strongly) that life in fact will naturally arise in the universe under given conditions, and thus life is ubiquitous and intelligent life is common.

But finding life on Mars that seems to have the same origin as Earth life (whether it started on Mars, or on Earth, or even elsewhere)? Meh. That tells me nothing about the commonness of life in the universe.

There's more to life forming on other planets than just having water. Your solar system and planet needs to form in a stellar nursery based in a nebula that has high phosphorus content. Most stars don't have enough phosphorus to get life going. The ones that do are fairly rare.

That being said fairly rare in a universe with trillions of stars still leaves billions of planets with the potential for life. So its plenty possible for life on other planets to exist.

a reply to: Soylent Green Is People

Life on Mars, in common with Earth may be more valuable than your assertion.

If life can move between two celestial objects of this distance... It could support a viewpoint that life may organically permeate in the universe, and does not require intelligent intervention to thrive beyond one body or one system. Maybe "dumb" organisms could get here as readily as many assume intelligent ones could.

a reply to: Archivalist

Maybe.

Maybe not so much.


So, if we find life on Mars, it should be genetic cousins?

originally posted by: Archivalist
a reply to: Soylent Green Is People

Life on Mars, in common with Earth may be more valuable than your assertion.

If life can move between two celestial objects of this distance... It could support a viewpoint that life may organically permeate in the universe, and does not require intelligent intervention to thrive beyond one body or one system. Maybe "dumb" organisms could get here as readily as many assume intelligent ones could.

I think the idea that Mars seeded Earth with life via an ejected space rick is one thing, but saying that life can be seeded in a similar fashion across the galaxy or even hop from galaxy to galaxy is, in my opinion, far less likely.

The question is: How common is abiogenesis? We know it happened once (somewhere), but is it an extraordinarily rare event, or is it a relatively simple thing given some not-too-uncommon existing conditions (or somewhere in between)?

Finding that Mars seeded Earth would not answer that question.

a reply to: TheConstruKctionofLight

Well, you know me by now.

I am a massive lefty after all, so I do not over much care about higher taxes, if it gets the people what they need, and if it gets science further forward than it was.

originally posted by: Phage
a reply to: Archivalist
So, if we find life on Mars, it should be genetic cousins?

If panspermia is an actual thing, it could be likely that all the same kind of life would be similar within a particular space neighborhood. If the entire solar system moved through a cloud of freeze dried bacteria, for instance, that rained down on us as micrometeorites any life evolving on the various planets and moons would have the same starting point. It would spread around our system like spores.

Again, though, space is just so damned big. And we think Mars is "close," but it's really, really far away. So who knows?

EDIT: I like how these micrometeorite hunters aren't out tromping around the desert, but rather up on the roof with a scrub brush.

a reply to: TrueBrit

I wrote

Living in your world you should be checking the 200 odd vehicles you may run across everyday to make sure they've had their brakes serviced otherwise you shouldn't be leaving your front door.

Funny how you ignored the more on topic exercise in logic.

I thought nitrogen was a key element to life in any given solar system. I know that there are other building blocks like h2o and hydrogen but I thought nitrogen was key too.

a reply to: CirqueDeTruth


BASSPLYR had it right too. The list should be: H2O, N, phosphates, and maybe some metals (we need magnesium, calcium, and selenium for our brains to work). With some energy, you can get more complex reactions happening (the classic is lightening but any source really).

The reduction-oxidation (redox) cycle can happen (respiration). That gives way to ATP cycle which is crucial to life as we know it.



As far as panspermia goes (and phosphates) there is a new study out, An interstellar synthesis of phosphorus oxoacids, where instead of putting earth chemicals in a jar and adding lightening ("Alive! It's ALIVE!!! ALIVE!!!!!), they did the same but made the conditions of space...

In an ultra-high vacuum chamber cooled down to 5 K (-450℉) in the W.M. Keck Research Laboratory in Astrochemistry at UH Mānoa, the Hawaiʻi team replicated interstellar icy grains coated with carbon dioxide and water, which are ubiquitous in cold molecular clouds, and phosphine. When exposed to ionizing radiation in the form of high-energy electrons to simulate the cosmic rays in space, multiple phosphorus oxoacids like phosphoric acid and diphosphoric acid were synthesized via non-equilibrium reactions.

"On Earth, phosphine is lethal to living beings," said Turner, lead author. "But in the interstellar medium, an exotic phosphine chemistry can promote rare chemical reaction pathways to initiate the formation of biorelevant molecules such as oxoacids of phosphorus, which eventually might spark the molecular evolution of life as we know it."

phys.org - Did key building blocks for life come from deep space?

The method means that all our building blocks come from our galaxy from the earth, to the water, to the needed phosphates, to our sun fusing elements, all these things had to happen, stellar fusion, earth coalescing into a mass with a magnetic field, an atmosphere, water, just the right distance from the sun, heck, even the moon to help churn the tides!

So stop littering! This is it as far as we know. Be kind to the magnetic field. Stop throwing your g'rette butts on the ground, and praise the She has allowed us to grow on the surface!

Amen!

originally posted by: TEOTWAWKIAIFF
So stop littering! This is it as far as we know. Be kind to the magnetic field. Stop throwing your g'rette butts on the ground, and praise the She has allowed us to grow on the surface!

I think the fact that we crawl around like scum in a thin layer of moist air sandwiched between molten rock and untold billions of miles of sizzling cold/hot nothingness is due more to our own tenacity than Gaia's desire to have us around. She does pretty much everything she can to kill us with tsunamis and earthquakes and meteorites and fires, etc., but so far we've managed to survive it (barely).

a reply to: Blue Shift


I would like to think that we are an intricate dance, that was chanced upon... in the awesomeness that was the birth of our universe. Lets hope the dance... danced on.

a reply to: SaturnFX

www.scienceworldreport.com...

There are things that can live in boiling water.....

originally posted by: Blue Shift
She does pretty much everything she can to kill us with tsunamis and earthquakes and meteorites and fires, etc., but so far we've managed to survive it (barely).

Meh -- Those things kill humans and other complex life. Life in general is mostly unfazed by such events.

It would take a whol alot for life on Earth to be gone. Even if humans soon go away, Earth will probably hardly notice we were ever here at all (after a blink-of-an-eye timeframe of maybe a couple million years after humans, or even far less).

originally posted by: Soylent Green Is People
It would take a whol alot for life on Earth to be gone.

Well, the universe specializes in those types of things that could easily scour the planet lifeless. We've been relatively lucky, so far.

originally posted by: Blue Shift

originally posted by: Soylent Green Is People
It would take a whol alot for life on Earth to be gone.

Well, the universe specializes in those types of things that could easily scour the planet lifeless. We've been relatively lucky, so far.

Surface life? Maybe. To completely sterilize the planet (including the life that could be found miles deep) would take a monstrous event that (IMHO) is not that likely to occur on any particular planet given, say, a several billion years timeframe.

I suppose a GRB or a supernova a few dozen LY away might do a relatively good job scouring the planet and maybe stripping away most of the atmosphere, but that is not a case of "we are lucky that hasn't happened yet" because such events are rare enough that it is not likely to happen to Earth in, say, a 9 billion year past and future time frame. Even then, there might be some life that hangs on is some deep crag far beneath the surface.

Granted, the Sun that will eventually swell up and potentially burns us to a crisp or devours us whole, but again it's not that we are just "lucky" it hasn't happened yet. That is not a likely scenario for about another 4 or 5 billion years.

I never understood the whole water thing... sure, water is essential to carbon based life forms, no doubt. But Is it crazy to think that alien life might actually rely on ammonia or methane or some other solvent besides water?

A2D

a reply to: Blue Shift


God own image, eh?

Lol! The fact there have been several ELE also says something. Now here we are killing our own planet! Plastic and plutonium planet, lifeless for hundreds of thousands of years. What strange naked mokeymen we are!

originally posted by: Agree2Disagree
I never understood the whole water thing... sure, water is essential to carbon based life forms, no doubt. But Is it crazy to think that alien life might actually rely on ammonia or methane or some other solvent besides water?

A2D

Science in general agrees with you. There are several mainstream science examples of people trying to understand what other solvents could be used by life, and what that life would look like, and how that life would function.

It's important to understand how such hypothetical life might function because if we ever want to know it when we see it, we need to understand that.

Right now we look for "life as we know it" mainly because it's the one type of life that we could readily recognize if we every do come across it. We understand what biosignatures "life as we know it" would leave behind. So we know what to test for when looking for that life.

However we don't really know what biosignature "life as we don't know it" would leave. We don't know what kinds of tests should be developed to look for that kind of life. If we ever send a probe to Titan looking for life that uses methane as a solvent in lieu of water ( and that WOULD be "life as we don't know it"), we would need to have some understanding of that kind of life so we could send the right tests on the spacecraft.

When we begin to look at the spectro-analysis of the atmosphere of exoplanets looking for biosignbatures in the atmosphere (such as what the James Webb Telescope might do), we could look for elemantal oxygen in excess, becuase that's what "life as we know it" would produce. However, what other chemical imbalances might we find that could indicate the existence of a life that uses -- say -- Ammonia as a solvent, or uses boron or silicon in place of carbon? (it turns out that ammonia would be a good solvent for boron-based life).


Here are links to a couple of interesting articles, one about other elements that might be used instead of carbon (some of the ideas are way out there), and an article about other possible solvents besides water that some life somewhere might use:

10 Hypothetical Forms Of Life

Why Water? Toward More Exotic Habitats


Below is a paper on the general way we could be looking for life as we DON'T know it - i.e., what general items should we be looking for (link opens directly to an 6-page PDF file):

Searching for Alien Life Having Unearthly Biochemistry