
Rogue planets could outnumber the stars - dnetesn
https://phys.org/news/2020-08-rogue-planets-outnumber-stars.html
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fernly
It's a bit boggling that they plan to find "rogue" planets by
"microlensing"[2]. To quote from [1]

> The mission will stare at the a dense star region toward the direction of
> the center of our Milky Way galaxy to observe microlensing events.

So you have a series of images of a field full of thousands (tens of
thousands?) of stars, and you ("you" meaning "a great honking bunch of
computer logic") compare one image to the next looking for _one_ of the stars
to have briefly doubled, or turned into a little ring. And then you derive a
lot of info from that brief distortion event.

[1]
[https://roman.gsfc.nasa.gov/faq.html](https://roman.gsfc.nasa.gov/faq.html)

[2]
[https://en.wikipedia.org/wiki/Gravitational_microlensing](https://en.wikipedia.org/wiki/Gravitational_microlensing)

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mromanuk
If humanity is still around in a few hundred million years, they could use the
earth as the vessel to escape the sun before it devour us.

[https://www.space.com/22471-red-giant-
stars.html](https://www.space.com/22471-red-giant-stars.html)

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sbierwagen
For the confused: Nancy Grace Roman Space Telescope was formerly the Wide
Field Infrared Survey Telescope. They renamed it in May.

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optimalsolver
The general Bel Riose had his military headquarters on one of these things in
Asimov's Foundation and Empire.

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sxp
> Johnson said these planets are not likely to support life. "They would
> probably be extremely cold, because they have no star," he said. (Other
> research missions involving Ohio State astronomers will search for
> exoplanets that could host life.)

This depends on the nature of the planet. Some planets with internal heat
sources like Earth or Jupiter wouldn't be frozen. They wouldn't have liquid
water on their surface, but they might have warm and habitable conditions
somewhere in the planet for certain definitions of "habitable".

 _Passages in the Void_ is a set of stories from Kuro5hin where I first read
about rogue planets sustaining life:
[http://localroger.com/](http://localroger.com/) They were written by the same
author as _Metamorphosis of the Prime Intellect_ and are interesting sci-fi.

~~~
dreamcompiler
Thanks. I was just about to ask if there was any good sci-fi about
civilizations living on the internal heat of a rogue planet.

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ISL
From a numeric standpoint, this seems like a reasonable conclusion. For the
system we know well, there are eight times as many planets as there are stars.
A lot of systems in which exoplanets have been observed are known to have more
than one planet.

The only way this is unlikely to be the case is if planets remain strongly-
bound to stars.

~~~
hliyan
Also from an intuition / thought experiment standpoint: stars form through
coalescing mass. Only a subset of such coalescing masses reach the special
conditions needed for fusion ignition. It follows that the general case is
that of masses that fall short of that threshold.

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m3kw9
More likely these planets harbour super advanced life as the don’t need to
depend on an external energy source, exposed to planetary event risk, and can
control their own fate. Maybe they can even change trajectory given their
advancement

~~~
qayxc
I'm afraid that doesn't follow at all.

Life requires an energy source and the only energy sources a rouge planet has,
are leftover heat from its formation process and nuclear decay.

The energy released by geological processes is too localised and too little to
allow for widespread higher lifeforms.

Even the comparatively active Earth doesn't generate enough heat on its own to
keep its oceans liquid (e.g. 100mW/m² at the oceanic crust and <70mW/m² at the
continental crust) or a gaseous atmosphere of any kind.

In order to generate enough heat to keep a liquid ocean and an atmosphere
(both are required for higher lifeforms as of our current understanding), the
planemo needs to be quite large or have at least one big moon in a close
orbit.

The first case is very likely to generate an ice giant like Neptune or Uranus,
both highly unlikely to harbour any kind of life.

The second case is probably very rare - the event that led to the ejection of
the planet would've also affected any moons. In addition, close orbits either
rapidly decay (see Deimos on Mars) with the moon crashing onto the surface
within just a few million years; or they recede over time due to the exchange
of angular momentum between the two bodies (see our Moon).

In conclusion, while planemos may indeed harbour microbial life in the form of
extremophiles living in their crust, any multicellular life is very unlikely
to have survived the ejection event and subsequent loss of a host star.

Formation of life on a free floating planet is very improbable and "super
advanced" life requires stable conditions over billions of years and
sufficient energy, which simply isn't available for the reasons mentioned
above.

Feel free to correct me if I got something wrong, though.

~~~
m3kw9
If they are advanced enough, they would have even better methods than nuclear
or fission power. More advanced methods of energy generation.

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apotatopot
Some of the stuff being announced about space seems to me like scientists
restating stuff we should've known 50 years ago. Like, our star has more than
2 planets around it. If that's the case with lots of stars, then it's obvious
there would be of a higher number of planets going "rogue".

~~~
nend
Well, science doesn't really operate by assuming what the truth is. If it did
it wouldn't be science.

And if it's so obvious that we should've known this 50 years ago, you could've
gone down in history as the scientist who discovered this truth. But instead
you're complaining on the internet about other people trying to prove it.

~~~
tachyonbeam
Actually, informed guesses make a lot of sense when we have limited data.
Science doesn't operate by assuming that we know nothing outside of what we
have evidence for. That wouldn't be logical at all. That being said, it is of
course interesting and valuable to confirm our hypotheses.

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database_lost
Maybe someone with more knowledge on the subject could answer, but could a
much larger than expected number of such bodies partially explain Dark Matter?

~~~
rudolfwinestock
No. Being ordinary matter, these objects occlude light. If there were enough
of them to make up for dark matter, or even a large fraction of it, then we
wouldn't be able to see much past our galaxy.

~~~
skohan
I thought "dark matter" literally refers to any matter which is not emitting
light, and the speculation about there being some "spooky" form of dark matter
is only to account for the sheer quantity which must exist but we can't
observe

~~~
zuminator
One of the odd characteristics of dark matter, aside from being dark, is that
it forms halos around galaxies, but within those halos the dark matter is
distributed evenly; it doesn't collapse into clumpy matter. Stars and planets,
on the other hand, clump and cluster. If there were sufficient numbers of
rogue planets to account for dark matter, there would have to be thousands or
millions of rogue planets for every star that we can see. At that density they
couldn't stay hidden -- over cosmic timescales they would be attracting each
other, forming clumps that would partially occlude stars, and turning into
stellar nurseries with detectable frequency.

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keithwhor
I think it's kinda cool to consider that rogue planets / brown dwarfs [0]
could be candidates for extending human life beyond the solar system post-Sol.
Assuming we have enough fissile material (or master cold fusion) to perpetuate
the civilization's energy requirements, we could explore the stars in darkness
for eons.

I'm not sure how likely they are as candidates for life to emerge
spontaneously, it seems like there's a very high energy input requirement over
billions of years (Sol -> Earth) to get anything close to human
civilization... but it's cool to think that, perhaps, some future humans could
settle a planet eternally cloaked in darkness. Adapt to the reality of that
planet over generations... and be unable to acclimate to life near stars at
all.

Also, post-Andromeda collision, is this a _necessary_ future for posthuman
life? [1] Billions of cold worlds will be flung into the far reaches of the
Universe.

[0]
[https://en.wikipedia.org/wiki/Brown_dwarf](https://en.wikipedia.org/wiki/Brown_dwarf)

[1]
[https://en.wikipedia.org/wiki/Andromeda%E2%80%93Milky_Way_co...](https://en.wikipedia.org/wiki/Andromeda%E2%80%93Milky_Way_collision)

~~~
kzrdude
I think the Andromeda collision is likely to not even disturb our solar
system.

Just like asteroid fields in movies are way too dense, it's easy to
overestimate what the collision means. It's two _galaxies_ that collide, but
their parts don't. Their individual star systems may all pass around each
other quite well, for the most part.

~~~
nojokes
Maybe, but there is also this:

As of 2006, simulations indicated that the Sun might be brought near the
centre of the combined galaxy, potentially coming near one of the black holes
before being ejected entirely out of the galaxy.[11] Alternatively, the Sun
might approach one of the black holes a bit closer and be torn apart by its
gravity. Parts of the former Sun would be pulled into the black hole. [0]

[0]
[https://en.wikipedia.org/wiki/Andromeda%E2%80%93Milky_Way_co...](https://en.wikipedia.org/wiki/Andromeda%E2%80%93Milky_Way_collision)

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kiba
There's nothing preventing our descendent from steering the sun by the time
our galaxy collides with the Andromeda galaxy.

~~~
DrAwdeOccarim
For fun, how could we do that?

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svachalek
Kurzgesagt video on this:
[https://youtu.be/v3y8AIEX_dU](https://youtu.be/v3y8AIEX_dU)

~~~
DrAwdeOccarim
Thanks for sharing. Reminds me of the Wet Hot American Summer line about how
we are all passengers on starship earth!

