
Could the Earth be an evaporated gas giant planet? - mickfaraday
https://demystifyingscience.com/blog/is-earth-captured-rogue-chthonian
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perl4ever
"It is not apparent yet that such Rogue planets are regularly traded between
star-systems and subsequently participate in serial evaporative events and the
proposal may seem like a long shot, but on astronomical time scales the
unlikely can become commonplace."

It sounds a bit Velikofskian.

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mickfaraday
Yes, Michael Lund of CalTech updated the Velikofskian hypothesis:
[https://arxiv.org/pdf/1903.12437.pdf](https://arxiv.org/pdf/1903.12437.pdf)

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pdonis
The fact that this paper appeared in April 2019 in a journal called "Acta
Prima Aprilia" should give you a clue to how seriously to take it.

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tzs
The fact that the paper uses “CalTech” was the big clue for me. Also check out
the references at the end. Some big clues there too.

~~~
wsc981
Some really raging clues there:
[https://www.youtube.com/watch?v=lcHy8xEt2QI](https://www.youtube.com/watch?v=lcHy8xEt2QI)

~~~
GeorgeWBasic
That video cuts off the best part, where he says "Godspeed".

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hirundo
"The Chthonian process effectively selects for retainment of water and carbon
dioxide, which are heavy and tend to rain back down upon condensing in the
upper atmosphere."

So earthlike planets would be more plentiful than otherwise. This could be a
boon to scifi plots that entail conveniently breathable atmospheres. It would
also tend to support the strong anthropic principle.

~~~
Razengan
> _This could be a boon to scifi plots_

But can they outgrow the trope of every alien being a human-in-a-mask?

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azernik
Not until CGI aliens with non-humanoid body plans become cheaper than masks on
human actors.

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koheripbal
It's the relatability to the audience that mandates they have human faces. ...
because humans can only interpret the facial expressions and emotions of other
human faces.

Star Trek was never meant to be Sci-fi so much as soap opera in space.

~~~
azernik
Farscape did pretty well with having relatable characters played by puppets.

~~~
simcop2387
I'd agree, but the faces of all the regular characters were very human-esque.
Even Pilot's face was puppetted to react vaguely human.

~~~
azernik
Still a very big departure from humans with masks.

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pfarnsworth
How can a captured planet ever maintain a stable, almost perfectly circular
orbit around the Sun, at a plane that almost exactly matches the rest of the
planets? It's impossible. The only way this can be explained is if all the
planets were created together at the same time.

~~~
echelon
This argument seals the deal. The probability of getting that _just right_ is
vanishingly small.

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anticensor
AFAIK Nitrogen in the initial atmosphere rules this out.

~~~
perl4ever
Is there a succinct explanation of why some terrestial bodies in the solar
system (Earth, Titan, Triton, Pluto) have mostly nitrogen atmospheres, but
others (Mars, Venus) are mostly carbon dioxide instead?

I mean, aside from specifics about each, what's the pattern that you would
apply to an arbitrary planet?

~~~
elihu
According to wikipedia, Venus' atmosphere is about 3.5% nitrogen and its
pressure is about 91 atmospheres. So, technically Venus doesn't have a lack of
nitrogen (it appears to have about 3 times as much as Earth), it has an
extreme abundance of carbon dioxide.

Something interesting I didn't know is that apparently Venus has almost no
plain oxygen.

Mars, on the other hand, doesn't have much nitrogen. Perhaps that's
attributable to the relative lightness of N2, which would be more prone to
float off into space than the somewhat heavier CO2.

~~~
gnulinux
Earth atmosphere is 0.04% CO2. Why does Earth have such little CO2? Is maybe
used by life on early Earth?

~~~
cryptonector
Yes. Earth used to have a lot more CO2. Then photosynthesis in the oceans
created an oxygen crisis.

~~~
chrisco255
"The cyanobacteria producing the oxygen caused the event which enabled the
subsequent development of multicellular forms." Seems like it was ultimately a
win.

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hindsightbias
Embedded link is very intersting
[https://wfirst.gsfc.nasa.gov/exoplanets_microlensing.html](https://wfirst.gsfc.nasa.gov/exoplanets_microlensing.html)

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pfdietz
A planet formed in another star system would very likely have very different
isotope ratios than one formed here. Earth has very similar isotope ratios for
most elements to meteorites.

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valuearb
How do planets migrate?

~~~
tdy721
Through the atoms of progenitor stars long since gone supernova. Probably
neutron stars too!

Or also by chance?

~~~
valuearb
I know tidal curves have increase the moons orbit, I’m struggling to think of
anything (outside massive collisions) that would cause planets to move closer
to their stars, or move to new ones.

~~~
nfg
Orbits can be quite unstable, for example read (one theory) or the early
dynamics of the solar system:
[https://en.wikipedia.org/wiki/Nice_model](https://en.wikipedia.org/wiki/Nice_model)

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daveslash
No.

At least, that was my _knee-jerk_ thought, according to _Betteridge 's law of
headlines_. After reading through it, I do find it an intriguing hypothesis.

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retpirato
NO. If solar wind caused a gas layer to evaporate, Earth shouldn't have the
atmosphere it does. This planet should be like those surrounding it. Those
same solar winds/radiation would have made sure of that. The issue I have with
this is the same issue I have with evolution. If conditions were not created
to favor life why are we the only planet with any known life & which is
perfectly suited to a variety of life? Do you really think that's a
coincidence? Scientists are constantly coming up with one ridiculous theory
after another to explain why no evidence of life has been found outside our
planet instead of just acknowledging that this planet is unique because it was
designed that way.

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rowanG077
Huh? No scientist claims to have ultimate knowledge of why there is life on
earth. But to claim that Earth was created for life is leap too far. I mean we
used to believe storms where conjured up by the gods because we didn't
understand how they really are created. What you are saying is essentially the
same. We don't know so it must have been created. You are essentially invoking
the God-of-the-gaps fallacy.

~~~
grayed-down
Maybe not created, but...tweaked?

