Space dust that regularly hits Earth could contain proof of alien life If we want to find evidence for alien life we don't need to keep looking for chemicals in exoplanet atmospheres or distant radio signals, says a Japanese astronomer. Instead, we should be studying the thousands of micrometer-sized bits of interstellar dust that hit Earth every year. University of Tokyo Professor Tomonori …
This is an excellent description of the chance of life in the Universe, for years we've been looking for distant radio signatures but never considered how life evolved on our planet. Dr. Neil Shubin has released several books that explain how we became life - they are all wonderful and very helpful to read - if you find this article interesting then start reading Neil Shubin's explanations, he's so damn smart!
We know that life on our planet changed when the dinosaurs were extincted after an asteroid struck the Earth but had it been a bigger asteroid then our "life" would have been reduced to dust in the universe, which landing on another planet could have evolved into new life. I see the evidence described by Neil Shubin as virtual proof that life exists everywhere in the universe although looking at our planets history then the chances of intelligent life in the universe is very low, but not non-existent. However plants and fish may be surprisingly common because they have evolved so easily in our planetary environment although the chances of seeing anything like this on the rest of our sun's planets is virtually zero, life on Mars is the only slight possibility locally. But 40 light years away is seem almost 100% likely.
Lot's of people have spent their entire careers considering how life evolved on our planet.
Panspermia is a bit of a cop-out and unnecessary. It suggests the chemicals needed to spark life came from a biome rather than lifeless coincidence but those chemicals are pretty common in space so while not ruling out panspermia it doesn't really matter.
As for intelligence, I'd suggest it's a reasonable probability once you get past the really serious roadblock - getting from single-celled to multi-celled. Here life popped along pretty quickly then didn't do much for a few billion years until about 600my ago when the first macroscopic multicellular life emerged (the first microscopic multicellular could be as much as 1by earlier - still being debated). The wormy things wriggled about for a few dozen million years then - ta da - The Cambrian Explosion - all hell breaks lose, pretty much every biological line is started, diversity goes crazy trying to find the best fit for any available niche. So once you have "plants and fish" you are well on the route to the possibility of intelligence emerging.
"Intelligence" can take many forms, our communicating, tool using brand of intelligence may not be that common but cetacean and cephalopod type intelligence could equally well exist. All that is before you start thinking about "it's life Jim but not as we know it" where all bets are off.
The other key factor is that whilst the circumstances required may make the chance very small, you have to couple it with the size of the universe and the amount of planets therein, which is very large.
That's even leaving aside the valid points raised about what constitutes life. Given that up until the last couple of hundred years or so, Earth would have been missed by anyone just looking for radio emissions...
So even if the chances of getting the right conditions are slim, the number of "tries" at achieving them is large and the two factors mitigate one another somewhat...
"Panspermia is a bit of a cop-out and unnecessary. It suggests the chemicals needed to spark life came from a biome rather than lifeless coincidence but those chemicals are pretty common in space so while not ruling out panspermia it doesn't really matter."
And not forgetting, of course, the biggest cop-out of panspermia. For "life" to be travelling through space to "seed" planets, it had to start somewhere first. Whether that be a planet or clouds in space, somewhere, the building blocks of life had to form first.
We now know that the galaxy contains a lot of simple organic molecules such as ethanol. But on Earth, DNA largely disappears from fossils after a million years, and so does protein. A speck of dust travelling at 1/10,000 of the speed of light would take 40,000 years to get here from proxima centauri, so a journey of 100,000 years would cover 10 light years. Therefore there is a faint chance we could find a trace of life in a galactic dust particle.
This does mean the first life on Earth could have come from within our galaxy, but other galaxies are much too far away.
How do the dust particles managed to penetrate into the inner solar system against the prevailing solar wind? Considering the tails of comets this is quite strong compared to the mass of each individual dust particle, or have I misunderstood?
I can easily understand that gravitational attraction of small cm or mm sized particles could overcome the solar wind, but really small particles with such a low volume to surface area ratio would surely be another matter.
Or is the suggestion that an object like Oumuamua could have brought them in and deposited dust in the solar system? https://www.theregister.com/2023/03/23/firstknown_interstellar_solar_system_visitor/?td=readmore
El Reg's astronomer boffins, please advise.
> we don't need to keep looking for chemicals in exoplanet atmospheres or distant radio signals
Obligatory xkcd: https://xkcd.com/638/
The problem for the analysts will of course be that in the absence of origin context any 'life' related findings won't mean a lot in real terms. Context is a recognised issue for terrestrial archaeology, which is why digs rigorously record things like stratification as the work proceeds. And actually the same applies in geology. An 'interesting' pebble conveys nothing much unless it's known where it comes from. On top of which, if the dust comes from seriously far away it will have taken so long to get here that it will be anyone's guess what's evolved in the interim.
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