The recent story of A/2017 U1, the first asteroid we've seen that's likely of interstellar origin,
underscores the possibility that the study of other star systems directly, hands on,
is within our grasp and may happen far sooner than our ability to travel to those star systems
ourselves.
Up until relatively recently, other than the occasional comet, supernova or variable star,
we didn't have the equipment to view the universe at a level where the real action can be seen.
But now we do and we're seeing all sorts of odd things from gravitational waves coming
in from merging neutron stars to exocomets passing in front of stars light years away
showing that the universe is a very dynamic place.
But what's also becoming evident is that our solar system is not isolated from the rest
of the galaxy and indeed is a part of a galactic whole that not only exchanges information
through the electromagnetic spectrum, but also through materials.
Materials can come in a number of forms.
A/2017 U1 is believed to be an asteroid of interstellar origin, but it's also possible
that we could see comets from other star systems pass through the solar system in the future,
and there's even the possibility that several comets already in our solar system are actually
captured former exocomets.
And even the hypothesized planets nine and ten, if either exist, could be planets captured
from other star systems early in the sun's history, or even captured rogue planets that
may have originally formed in another part of the galaxy entirely.
But, as I touched on briefly in a recent video, these are not the closest interstellar materials
to us.
Grains of dust from the interstellar medium, and perhaps other star systems, are constantly
raining down on earth in addition to materials from many bodies in our solar system including
Mars in the form of meteorites.
These are all of immense scientific interest on many fronts, whether you want to study
the origins of the solar system or to establish if microbes once lived on Mars.
But I think the most interesting aspect, one that's almost entirely unexplored, is what
materials from other solar systems might tell us about life in the universe.
One almost certain given there is that we're going to find the building blocks of life
in these interstellar objects.
In fact, we already have with objects from our own solar system, amino acids have been
found in a class of meteorite known as the carbonaceous chondrites, the origin of which,
at least for some examples, are probably comets.
We also know that organic chemistry permeates the galaxy, seemingly most places we look
we see organics and materials from other solar systems are likely not going to be an exception,
especially when looking at exocomets.
But those are just the building blocks, not life itself.
Is it possible that we might find evidence of life itself in another star system locked
up in some interstellar asteroid or dust?
The answer is hypothetically yes, but very unlikely, unless you're willing to look and
wait for billions of years.
Which we may well do, we have plenty of time on our hands before the universe goes dark.
And the notion even applies to intelligent life.
It's possible that some day an asteroid exhibiting clear signs of having been mined might turn
up from outside the solar system.
I think the odds of this are astronomical, but it is within the realm of the possible
if you wait long enough.
And the disappointing if you happen to be an asteroid miner and the aliens already got
to the gold.
But as far as simple life, this is probably more likely, though it's hard to envision
much evidence of life surviving the environment of space for millions of years, it's a seriously
harsh environment.
Then again, preexistent fossils might.
Who knows if a sedimentary rock with clear evidence of fossilized life blown off a planet
in another star system long ago might come our way.
But you can also take this thinking from the opposite direction.
What from Earth might end up in deep space to be discovered by aliens?
Well, obviously some of our probes might, though only marginally so.
Those are needles in a haystack, and that might be a good thing.
If aliens find the Pioneer plaque and subsequently study earth and figure out it's not exactly
the warmest place in the universe, the first communication we get from an alien civilization
might be winter clothing designs.
But there are other possibilities.
Earth has been hit by asteroids in the past, and the possibility of ejected material exists.
Much of this would remain in the solar system, opening up the possibility that we may, probably
after centuries of solar system colonization, find rocks from very early in the earth's
history floating in space and that might tell us more about early life on earth than anything
left on earth can.
But ejection from the solar system is possible too.
Who knows what someone out there might someday find that originated from our planet.
But there is an interesting recent side note to these ideas.
In a paper by Arjun Berera, link below, he proposes a very novel idea.
It goes like this, space dust traveling at hypervelocity grazing the earth's atmosphere
could in itself propel materials from the atmosphere into space.
Most of this will just be atoms of oxygen and the like, but, given that there are microbes
and evidence of biology all through our atmosphere, that means that they too could get propelled
into space.
Some of that potential stuff, such as tardigrades and bacterial spores have been shown to be
able to survive the conditions of space, for a time.
But not long of a time, and exposure to the radiation of space probably wouldn't allow
something like that to preserve on geologic time scales.
But if it happened to deposit on something, say an asteroid or comet, or even the moon,
it might last much longer, or if still alive somehow establish itself through panspermia
within the solar system.
Interstellar panspermia would be much more difficult, over the immense amounts of time
that it would take to travel between star systems, it's hard to envision anything alive
making it that long.
But its chemical building blocks might, or even fossils of it, opening up the possibility
for life to arise again from the materials of long dead life from another system.
I also wonder what might fossilize and end up in space from the age of technology.
We make some materials that could, hypothetically, end up in ocean sediments and fossilize or
preserve to some degree for a very long time.
There's actually an obscure natural case of meteorites that fell half a billion years
ago preserving in the sedimentary rock in a quarry in Sweden.
Could this happen with evidence of our technology?
One can envision an almost sad scenario where an alien race some day finds sedimentary rock,
originally laid down in the Pacific ocean and then blasted into space by an asteroid,
bearing evidence of our long dead civilization in form of an artifact.
This strange remnant might be the first evidence the aliens have ever found of others in the
universe, and they might marvel at it and try to determine what it might have been.
Perhaps there are strange markings on it that they cannot decipher and it might end up in
a museum exhibit where generations wonder what this strange crumpled object sticking
out of a rock might say.
Might they build a supercomputer whose sole task is deciphering this strange code?
Maybe they will find more evidence over the millennia that lets them crack the code and
the greatest mystery in the future universe is "what exactly was a cheeto".
I say that partly in jest, but finding artifacts like that is possible, the remains of a glass
bottle embedded in sedimentary rock could last a very long time in deep space, and plenty
of our trash is certainly making its way into the oceans sediments.
And we do live in a universe that could be here for trillions of years, that's plenty
of time for someone to find something, but I find it interesting and even poetic that
interstellar grains, themselves perhaps holding unseen clues of life in the universe, grazing
the earth's atmosphere could be ejecting our life into space and may have done so for billions
of years only to end up who knows where.
The universe is a dynamic place indeed.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently advocating that A/2017
U1 be officially named Rama.
I first saw this in the comments section when I started reporting on the story and I love
it.
For those unaware this is in reference to Arthur Clarke's book Rendezvous with Rama
which is one of my favorites and I highly recommend it, though it's not good material
for reading in bed since you won't be able to put it down so for a real sleep aid check
out my books at your favorite online book retailer and subscribe to my channel for regular,
in-depth explorations into the interesting, weird and unknown aspects of this amazing
universe in which we live.