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Panspermia (wikipedia.org)
73 points by dyukqu on Oct 14, 2018 | hide | past | favorite | 44 comments

Ok, this is a bit of a tangent but this is a smart crowd and I’ve been wondering something.

Was reading about the Silurian hypothesis from NASA researchers, which talks about how hard it could be to detect a previous technological society in the geological record. (Harder than I’d assumed.) [1]

Given that — and climate change being top-of-mind — I was thinking about Venus and wondering: how certain/uncertain are scientists that Venus’s greenhouse effect wasn’t caused by a technologically advanced society, a very long time ago?

From my understanding, it’s so hot there that anything we’ve sent has burned up rather quickly. If it’s indeed very difficult to detect a previous civilization in the geological record on earth, what does that say about Venus?

1: https://en.m.wikipedia.org/wiki/Silurian_hypothesis

It boggles the mind. All of it. The scale of space, the scale of time, our own tiny brief existence in it. The possibility that several civilization collapses occurred right here and we wouldn't know it. The possibility that life elsewhere in the universe came and went and the light informing us of it won't reach us before we possibly burn out. Meanwhile we're just a flicker from a spent flintwheel.

The thing that gave me a particular "oh" moment was reading the study that correlated Earth's geologic events (mass extinctions, impacts, etc) timed to our Sun transiting through the spiral arms of our galaxy. Fun read: https://arxiv.org/pdf/1309.4838.pdf

We know very little about Venus. Unlike most people that think that Mars is a future human world, I think that either spacecraft or Venus will be our secondary homes in this solar system. All it takes is to get 40 kms off the ground in Venus and a human could walk outside. All you would need is oxygen, which is already trivially supplied with today's technology.

If we bio-engineered some plants to create pockets of lighter gas they could float in the air. Energy generation would be easy because of the thermal differential to the surface.

The biggest problem for being outside longterm (years) is the lack of a ionosphere of similar strength to Earth, but I think that could be tackled. The psychological impact of long days could also be partially mitigated by having the bioengineered pods use sails or engines to follow dusk and go in and out of it, simulating an earth day. But similar gravity and tons of potential compared to shitty Mars.

> If we bio-engineered some plants to create pockets of lighter gas they could float in the air.

Those plants would also need to be able live in an atmosphere that contains seven times more sulfuric acid than water vapors. It's not easy to sustain protein life outside of Earth.

Still a nicer place than Mars, I agree.

All the carbon that we are releasing into the atmosphere was there at the beginning, and was taken out by life. So I do think it's quite unlikely that a civilization can appear in a planet that has enough carbon on its crust to make it completely unsuitable for life.

Interesting - could you expand on this a little further?

(Edit: sounds like there’s been recent research suggesting there was a decent window of time where life might have had a chance to appear on Venus: https://www.scientificamerican.com/article/hellish-venus-mig...)

Yeah, I didn't take the Sun heating up into account. Whatever you take from astronomers is going to be better based (and take more factor into account) than my speculation.

That feels nonfalsifiable? Unless there's some persistent markers (oddities in the chemistry of the atmosphere, perhaps) there wouldn't be any way to know.

It's interesting to note that, regardless of actual origin of life, a significant exchange might have been occurring (or is still occurring) between Solar System bodies (judging by how we found a number of Martian meteorites on Earth). So if we find life elsewhere in the Solar System, it might be quite compatible.

The idea is mentioned in Kim Stanley Robinson's "2312", where simple organisms exist in Enceladus's ocean, and some people inject them for fun (with neutral or mildly beneficial effects).

I, for one, have been busily working in my backyard launching nano-rockets filled with water bears that I've manipulated via CRISPR to contain encoded messages of funny dad jokes.

But then, disaster strikes!

It transpires that when encoded into quaternary, and thence to base pairs, the joke "What lies at the bottom of the sea, shivering? A nervous wreck!" encodes a viral sequence for a novel but entirely deadly pneumatic disease.

When one of the rockets misfires and detonates in a Bernard Matthews turkey farm, all human life on this planet is quickly extinguished.

100 million years later, a crashed alien spacecraft is discovered by the inhabitants of Gliese 15s, triggering a cultural revolution involving terrible puns and mildly amusing logical inconsistencies.

Aaron Diaz may have beaten you to that particular punch: http://dresdencodak.com/2009/07/12/fabulous-prizes/

There’s an interesting paper mentioned: The DNA of Bacteria of the World Ocean and the Earth in Cosmic Dust at the International Space Station https://www.hindawi.com/journals/tswj/2018/7360147/

The idea explained in a computer animated video https://www.youtube.com/watch?v=kWChhdIgT6Q&gl=BE

The source used in the music video: https://archive.org/details/sims_panspermia_1990

I don't see it mentioned on wikipedia, but one tin-pot theory I heard once and quite liked was:

* The universe at the moment is on average large, cold and quite hostile to life.

* At some point in the past all the energy in the universe was concentrated roughly at one point

* So, in between, the universe was a soup of energy that would have been, on average, warm, comfortable and conducive to life.

It dovetails with this because it is a plausible "why would life have evolved somewhere else but not here" counterargument. I wouldn't buy it though, it seems likely to me that earth's life is a local phenomenon.

From https://en.wikipedia.org/wiki/Chronology_of_the_universe:

> Between about 10 and 17 million years the universe's average temperature was suitable for liquid water (273 – 373K) and there has been speculation whether rocky planets or indeed life could have arisen briefly, since statistically a tiny part of the universe could have had different conditions from the rest, and gained warmth from the universe as a whole.

But temperature alone isn't sufficient for life as we know it. Here on Earth we enjoy an atmosphere providing us with oxygen, a large planet protecting us from most meteor impacts, and a magnetic shield against radiation.

Life didn't start out breathing oxygen, oxygen was actually a waste product and the introduction of oxygen into the atmosphere was a disaster for a lot of the life existing at that time... https://en.m.wikipedia.org/wiki/Great_Oxygenation_Event

What do you think the probability of each of those factors is? Even if they're each 1 in 100, there leaves an enormous likelihood of those conditions existing many times over in the vastness if the universe.

This has received some serious consideration in Loeb's "The Habitable Epoch of the Early Universe" https://arxiv.org/abs/1312.0613

Proxima and Ultima by Stephen Baxter hit along this theme and are a pretty good read.

One argument that life is common is that life appeared very early on Earth, and so by inference Origin of Life is likely to be an easy process.

But there's another possibility: perhaps panspermia is easy in the dense star cluster the Solar System formed in, which packed 1000 or more stars into a cubic parsec. In that case, if life originated early, it could then spread to all the other star systems in that cluster. This would amplify the statistical weight of "early" OoL. Most planets on which life gains a foothold would be those in which OoL happened to occur in this birth nursery, and then spread.

This concept has interesting implications for SETI and science fiction. Life might be extraordinarily rare or absent elsewhere in the universe, but there may still be thousands of other systems in our galaxy that were seeded along with ours. They'd be spread out now around a ~180 degree arc around the center of the galaxy.

I had a conversation with someone about cryonics a few years ago, and they brought up an ineresting problem with the viability of cell over long periods of time. DNA repair is an active process, and if frozen in Liquid Nitrogen, all molecular activity stops, yet radiation damage can still occur. It seems like on a long interstellar voyage, gamma rays and other cosmic rays would turn an organisms DNA into soup.

Is it possible that self replication was ignited at the time of heavy bombardment? It's really strange how origin of Life on Earth is correlated with this time. One possibility might be that our planet was covered with ice at this time while constant bombardment should produce a lot of phase shifts and randomness, contributing to significant recombinations of available molecules in water. It's a kind of top-down approach.

Check out Nick Lane's videos on his theory of life origins on earth. Fascinating stuff.

A theory that can never be tested is as much a religion as any.

I don’t get it... how is this a religion? Doesn’t a religion set out rules for living and have weekly services and stuff?

Also isn’t a theory a hypothesis that has already been tested and supported with evidence?

Religion is choosing to believe that something is true without evidence.

I don’t think that’s right. Here are some definitions from Google:

the belief in and worship of a superhuman controlling power, especially a personal God or gods.

a particular system of faith and worship.

a pursuit or interest to which someone ascribes supreme importance.

I don't see anything in the idea of Panspermia that dictates how should I conduct my life and if I can eat pork or not.

..although there's nothing wrong with a panspermia religion.

OP, did you just watch "How the universe works"?

:-) Nope, I was reading an article: The Milky Way Could Be Spreading Life From Star to Star -> https://www.universetoday.com/140223/the-milky-way-could-be-...

This just pushes the problem of abiogenesis one step back.

I think some believers see a steady state universe. Life then becomes a boltzman brain. But I think panspermia is likely a thing and I think life naturally arises in open dissipative systems. Get a rock, water, and a heat source and wait a few million years...

> Get a rock, water, and a heat source and wait a few million years...

And you get a warm, wet rock.

Statistics, probability theory and physics don't work like that. You can't arrive at the conclusion by stating a premise and wishful thinking.

Why does everyone claim to know things they don't know? The more I know the more stupid popular opinion becomes.


I think what's missing from your closed system is some kind of variation to induce change. Earth might not have enjoyed life without the rotation and revolution of the Earth generating conductive (and other) currents in the air and water.

Side note, I think you could make stronger points by not distracting with that kind of off-putting sarcasm.

Jeremy England got popular a few years ago for claiming that life is inevitable on nearly every planet. Hmm


Funny how we go from “we are the only ones here” to “lifs is everywhere” and Drake’s equation is a giant fudge:


So atheists are sure that creationism is silly but then postulate Multiverse Theory + Anthropic Principle and Life is Inevitable?

Let’s ALL be humble and say that, at this point, we have absolutely no idea how life began, and these are all speculative and unproven theories.

My wikipedia-chain for the past hour and a half: https://hedwig.orenhazi.com/misc/nerdsniped.jpg

I hope you're happy.

I remember they used a “Panspermia” animation for Pantera’s cover of “Planet Caravan” back in 1994.


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