One thing that isn’t too often thought about regarding the end of earth is that getting
baked or even swallowed by the sun are not the only possibilities.
In previous videos, I’ve covered some of the possibilities of what we might do to prevent
earth’s end billions of years from now if we’re still around.
But if we aren’t, or choose not to save earth, there is one possibility that has a
particularly interesting potential outcome in the far future.
In a 2000 paper by Greg Laughlin and Fred C. Adams, link in the description below, they
report that there is a chance, albeit a diminishingly small one, that a passing star could gravitationally
disrupt the solar system enough to eject earth out of the solar system entirely.
That stars will pass close by in the future is a given, I’ve detailed a number of them
that will come close to us in the future in videos on this channel, but the further into
the distant future we try to predict the harder it becomes to determine which stars will pass
by and what effects they may have gravitationally.
Stellar events of billions of years from now are essentially impossible to predict.
And there are a lot of other variables, for example the authors note that a binary star
system would disrupt things more than a single star system, and distance plays a prominent
role.
But, nevertheless they calculated that it could happen before the runaway greenhouse
effect starts due to the brightening of the sun as it ages.
There are two scenarios if earth exits the solar system if a star passes too close.
One is that it could be flung into deep space where its surface will freeze solid.
That would be the end of the surface biosphere of earth, if it’s still around, but geothermal
vents would persist in the oceans and life might just endure on, at least as long there
is enough radioactive decay in the planet’s core to keep things warm.
But there is another possibility.
Again, while the chances are very low, earth could get captured by the passing star and
begin life anew.
The odds would be beyond reasonable that we might end up in a habitable zone and the act
of migration alone would probably kill most surface and ocean life, but the microbes might
survive it at their vents and life that originated in this solar system may end in another.
On the other hand, we could just as easily get unlucky and end up with a star that just
happens to be preparing to explode.
But then again, if we’re still around, we might survive it using fission, fusion or
geothermal technology.
I would direct the interested to Greg Laughlin’s blog, link in the description.
In that he notes that that we would have tens of thousands of years of warning that the
star would be coming.
With proper planning, we might survive it and maybe even direct the process.
If we’re not here, perhaps some far future civilization may some day come across rogue
planet earth and thaw it out, and with any luck their astroarcheologists might find evidence
of us, perhaps what used to be a plastic water bottle preserved in a fossil layer, though
the longer the time that ensues, the less evidence there will be for them to find.
But that’s a topic for a future video, detecting dead civilizations including our own, should
we go extinct.
I find that topic interesting, but somewhat sad, I would hope that whatever civilizations
we might find in our universe are alive, well and friendly.
I hope they find us in similarly good condition.
But If we survive our infancy and become a far-flung space faring civilization, maybe
we’ll run across someone else’s ex-world from long ago wandering the cosmos as a rogue
planet.
As an aside, it’s possible, though unlikely, that this could happen sooner rather than
later, indications are that rogue planets are not rare and in fact it’s entirely possible
that the closest world not native to our solar system could be a rogue planet and sitting
within a few light years waiting to be discovered.
The chances are beyond low that such a planet might have hosted a civilization or life at
some point, mainly due to ejections being more a phenomenon of very young solar systems
instead of old ones, but it’s fun to ponder the possibilities nonetheless.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently eyeing the universe,
but not suspiciously, it’s nighttime and clear, so time to head out with the telescope
and be sure to 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.