Extrasolar Habitable Planets

Mars_B4_Moon · 2024-02-22 20:21:55

If Hycean Worlds Really Exist, What are Their Oceans Like?

https://www.universetoday.com/165838/if … eans-like/

Void · 2024-04-01 07:43:24

This article describes a measurement that says that Trappist-b is not habitable for non-human life.
https://www.msn.com/en-us/news/technolo … r-BB1kSuYx
Quote:

However, TRAPPIST-1 b, is the innermost planet and receives about four times the amount of energy that Earth gets from the Sun.

The indication is, no atmosphere. Which is not that surprising as it gets about twice the amount of solar radiation as Venus does.

The planet may resemble a larger version of Mercury, perhaps.

But I would hope that it was actually tidal locked. In that case perhaps ~40% of its surface might be in a rather permanent deep cold.

Such a world might harbor glaciation in the darkness, and under sufficient ice, perhaps even liquid water. Ice shell worlds we think exist such as Europa may have this in common with it. So, that actually that world might harbor life, if Trappist-b has volcanism under the ice. This is of course a "Maybe". It may have tidal heating due to the 6 other known planets and its star.

Such a world might be attractive to humans or similar beings, should they be able to travel to it. But I believe it is 40 light years away.

Other people look at Proxima Centauri-b and see a world that is just a bit larger than Earth. On a bet, my money would be that it does not have an atmosphere either.

I would be more interested in Proxima Centauri-d, which is closer to the star, and about 2 times the mass of Mars, I believe.

That world without an atmosphere, and tidal locked may have a hot sunward side, dry, and a cold darker side with ices. A technological society might do quite a bit with that.

https://en.wikipedia.org/wiki/Proxima_Centauri_d
Quote:

Proxima d is a sub-Earth at least one-quarter of the mass of Earth (or twice the mass of Mars), orbiting at roughly 0.029 AU (4.3 million km; 2.7 million mi) every 5.1 days.[2] It is the least massive and innermost known planet of the Proxima Centauri system. It is the least massive exoplanet detected with the radial velocity method as of 2022. Although Proxima d orbits too close to its star to have a habitable equilibrium temperature (which likely reaches 360 K (87 °C; 188 °F)[1] from about 190% of Earth's irradiation—assuming an Earth-like reflectivity, it is theoretically possible that Proxima d possesses polar regions with habitable temperatures.

But it could resemble Mercury and not be tidal locked, in which case it may have shadowed craters at its poles, with ices in them.

That world is perhaps the closest extra solar planet to us, accessible with our imagined technical abilities. It would have lots of energy, solar, and maybe geothermal. And if it did have ices in the cold places, might be quite a planet to set up camp on.

Done

Last edited by Void (2024-04-01 08:00:18)

Void · 2024-04-03 10:20:38

Although the planet described here may be at most marginally habitable, it does seem to be evidence that tidal locked planets can exist.

https://phys.org/news/2024-04-tidally-s … lanet.html
Quote:

First tidally locked super-Earth exoplanet confirmed
by Bob Yirka , Phys.org

I take encouragement from that. I have had further thoughts about tidal locked planets, with a lack of atmosphere. Those and Rogue Worlds as well.

The science and also the media communities seem to be obsessed about discovering life and even aliens with skill levels greater or less than ours. I don't tend to be that way. If it turns out to exist then it has to be processed by our culture, if they don't kill us.

It appears that Fusion is eventually going to become a real thing as per power plant potential. That and Orion Type Drives says that eventually, if the human race is able to avoid severe mass insanity, humans and their machines may go to interstellar planets, such as Rogues, and Tidal Locked ones. These are unlikely to have fostered competitive aliens. I consider that to be a good thing.

So, with the proper tools some of these worlds can be refashioned to a suitable use for humans and their machines.

Done

As for around Red Dwarfs, we might want to hope to find a Titan orbiting a Saturn. With a very cold Nitrogen atmosphere, and perhaps protected by a magnetic field from the parent planet as Saturn protects Titan. Having an energy source, a lot could be done with something like that.

Done

Last edited by Void (2024-04-03 10:44:26)

Mars_B4_Moon · 2024-04-12 10:57:37

NASA's planet-hunter TESS temporarily shuts off

https://www.spacedaily.com/reports/NASA … f_999.html

Void · 2024-04-13 11:07:19

Materials in this post suggest that solar wind does not strip atmosphere as much as was thought, in the cases of Venus and perhaps Mars:
https://newmars.com/forums/viewtopic.ph … 58#p221758
Quote:

The idea of a magnetic field for Mars has been an exciting one, but recent information suggests that it is not needed.
https://newmars.com/forums/viewtopic.ph … 05#p221605
If you go to minute 8.06 of this video it is suggested that the losses have not been that much: https://www.patreon.com/posts/interstel … -102029505
It is said that over 3.9 billion years they calculate that Venus would have lost .02 to .6 meters of water to the solar wind. And they think that Mars is somewhat the same.
I am willing to say that it is not certain how much good a magnetic field might do.
This will be interesting for Red Dwarf worlds as well. They may have greater power to hold an atmosphere than has been thought.
Done

Perhaps it will be discovered that a Red Dwarf might make some planets more Earthlike by stripping away a Hycean original atmosphere, and yet perhaps allowing a secondary atmosphere.

https://en.wikipedia.org/wiki/Hycean_planet

Done

Last edited by Void (2024-04-13 11:09:37)

Mars_B4_Moon · 2024-04-20 13:52:22

In search for alien life, purple may be the new green
https://phys.org/news/2024-04-alien-lif … green.html
Instead of green, many such bacteria on Earth contain purple pigments, and purple worlds on which they are dominant would produce a distinctive "light fingerprint" detectable by next-generation ground- and space-based telescopes, Cornell scientists report in new research

Mars_B4_Moon · 2024-05-05 03:15:33

Kepler part 2 is 'Made in China?

China Is Hatching a Plan to Find Earth 2.0
https://www.scientificamerican.com/arti … earth-2-0/
A satellite will scour the Milky Way for exoplanets orbiting stars just like the sun

The Earth 2.0 satellite is designed to carry seven telescopes that will observe the sky for four years. Six of the telescopes will work together to survey the Cygnus–Lyra constellations, the same patch of sky that the Kepler telescope scoured. “The Kepler field is a low-hanging fruit, because we have very good data from there,” says Jian Ge, the astronomer leading the Earth 2.0 mission at the Shanghai Astronomical Observatory of the Chinese Academy of Sciences.

Mars_B4_Moon · 2024-05-26 17:50:19

Marvel at the Variety of Planets Found by TESS Already

https://www.universetoday.com/167111/ma … s-already/

Mars_B4_Moon · 2024-06-06 03:04:59

NASA's Webb Telescope Observes Potentially Habitable Exoplanets

https://www.spacedaily.com/reports/NASA … s_999.html

Void · 2024-07-16 07:31:43

This has been on the internet for a while: https://www.msn.com/en-us/news/technolo … r-BB1pS6mN Quote:

Scientists Have Discovered a Habitable Eyeball in Space
Story by Darren Orf • 3d • 4 min read

I suppose it is more likely that the planet is not as hospitable as discussed. Even so, I have in the past considered what the biosphere of such a world could be like.

My first guess is that weather would be in the form of an oscillation. I believe that Antarctica can be like that.

The differential temperature between the sunny side of the planet and the dark side of the planet would build up, until a storm broke loose. Then a storm would sweep from the dark side with very cold winds. The temperatures would then equalize enough to still the winds.

If there were a shoreline of iceshelf, sometimes icebergs would break from it, perhaps in the still time the icebergs would travel back to the shore.

Supposing that there were nutrients in the water then perhaps multicellular life could exist. Fish like perhaps, and some of those could develop the ability to fly. And there might be penguin like creatures, seal like creatures. That would perhaps mean guano on the beaches which could lead to bogs and bog covered ice shelf.

Technological materials could be bone and shell, perhaps rocks from space, maybe the way to light a fire with those, and then fire would need to be of oil from killed animals I expect. But it might also be possible that some sort of tree could grow in the bogs.

But the gravity of the planet is likely so large that it would be very hard to get into space without some sort of method we do not know of.

Done

Last edited by Void (2024-07-16 07:44:33)

Calliban · 2024-07-16 10:18:24

There is really no way of knowing at present whether this planet is habitable or not. It appears to have about the right solar flux and isn't too big.

It actually makes relatively little difference from a human colonisation viewpoint if there are no other habitable planets in the galaxy. By the time we get that far, we will be living in space. More habitable planets simply means more competition. From a purely human viewpoint, a paucity of habitable worlds may be a positive outcome. A Mars-like world or even a Ganymede would be perfectly useful to future humanity.

Last edited by Calliban (2024-07-16 10:24:11)

Terraformer · 2024-07-16 10:55:30

Finding large numbers of planets with life would not be reassuring if you're worried about the "Great Filter". If Earth turns out to be an incredibly rare type of world, that's good news from a Fermi "Paradox" perspective.

Metaphysically I believe us to be alone. Our job is to no longer be alone. "Now no shrub of the field was yet on the earth, and no plant of the field had yet sprouted, for the LORD God had not sent rain upon the earth, and there was no man to cultivate the ground."

Calliban · 2024-07-16 17:08:46

Earth does appear to be quite rare. Most of the several thousand planets discovered so far appear to be larger than Earth and this doesn't appear to be detection bias. And most star systems mapped so far have much tighter orbits than the solar system. It is looking more likely that the Earth is unusual. That may be disappointing to SETI enthusiasts. But it probably means we don't have to worry about the Trisolarian fleet. And it is entirely possible that we are the only extant technological civilisation in the galaxy. That is in some ways daunting. But it does allow for practically unlimited expansion without conflict.

Technology extends the limits of habitability. None of the other worlds in our solar system appears to have been capable of developing an extensive ecosystem naturally. But technology would appear to allow Mars to be terraformed. With fusion based energy, the larger icy moons could be given breathable atmospheres over a long timescale and could probably support tundra ecosystems. Smaller icy bodies could be aquaformed. I am quite confident that humanity will ultimately spread life throughout the galaxy. With technology, we are not limited to those rare Class-M oases of life, like we see in Star Trek. The icy dwarf planets, comets and interstellar rogue bodies are within our reach as well.

Last edited by Calliban (2024-07-16 17:22:19)

Void · 2024-09-08 18:07:55

A planet around a dwarf star, that apparently has an atmosphere: https://phys.org/news/2024-09-nearby-su … -rich.html Quote:

September 6, 2024 report
Editors' notes
Nearby super-Earth has a sulfur-rich atmosphere, Webb observations suggest
by Tomasz Nowakowski , Phys.org

Quote:

"If confirmed, the detection of sulfur-bearing species in an hydrogen-dominated atmosphere around L98-59 d, a planet with a radius of 1.58 Earth radii, would be a significant result, as it lies right at the cutoff for planets to have retained their primary hydrogen-helium atmosphere," the scientists conclude.

A hell world actually, but a possible indicator of other possibilities.

Of course, the doom machine has gone on about how, red dwarf planets are not likely to be habitable.

Habitable, might want an atmosphere a bit like that of Earth. That in part would depend on the stellar wind of the star, the heating of the planet, and the age of the planet.

In some cases, it could be nice to have a planet out near 1% of Earth's solar flux, that would have a Hydrogen/Helium Atmosphere. That could keep it warm.

Or an ice planet the size of Earth that far out that would have lots of ices of CO2 and Methane and Ammonia.

But it looks like it could be possible that an Earth Sized planet could have a Nitrogen/Methane bases atmosphere, from the level of 25% to 1% of solar flux that the Earth has. It would be a cold world, but like Titan would have some things to offer.

I think it may not be impossible to have an Earth sized world with 50% of solar flux with a Nitrogen/Methane atmosphere, but it would need a protective magnetic field of consequence, I am guessing. That would be warmer than Mars if it had a 1 bar pressure atmosphere.

Other than that I would anticipate that small worlds like Mercury even if very hot could be valuable. If tidal locked then maybe with ice on the dark side.

Such tidal locked worlds without atmospheres would be useful if hotter than Mercury or colder than Mars, as one side would have a pointing to the sun that would really favor solar power.

But of course we cannot hope to get to such worlds at this time. But it is fun to have a better measurement of what may be possible.

Ending Pending

Last edited by Void (2024-09-08 18:20:37)

Void · 2024-10-01 09:00:30

https://www.msn.com/en-us/news/technolo … 31853&ei=9
Quote:

Planet Discovered Around Closest Single Star to Sun
Story by Jess Thomson • 2h • 4 min read
"We have detected a sub-Earth planet with a mass about half of the mass of Venus, or about three masses of Mars, in an orbit of 3.15 days—so the year in this planet lasts for about only 3 days," paper author and astrophysicist Jonay González Hernández of the Instituto de Astrofísica de Canarias, Spain, told Newsweek.

A small very hot Mercury perhaps.

To be honest, I think it is much more likely that the human race will descend into dark ages than to even expand into our solar system, from he behavior of human populations, so I am not very optimistic about travel between stars, but still, it is interesting to consider what could be done with such a world, if no other planets of consequence exist.

Even if no other planet of consequence did exist, there could still be an Oort cloud, and maybe some Dwarf Planets like Ceres, further out that could have some Ammonia and other ices.

The small planet discovered is presumed by me to more likely not have a significant atmosphere. I would suppose that it is either like Mercury with a 2/3 orbital rotational relationship or Tidal Locked. The polar areas I would suppose would be likely to be a bit like our Moon, Mercury, Ceres, or Mars. So, perhaps icy but no guarantees on that.

I am inclined to think that tidal locked, without significant atmosphere and with ices on its dark side would be the most useful to any human equivalent or more advanced life process. Such could include Ammonia and Water and Methane. The front side of course would have vast amounts of solar energy available.

So, not hopeless for an advanced civilization.

As always, I observe that most science is obsessed with discovering life on other planets. In this case they do not get what they want. But I suppose there could be another planet. My wish for that would be a cold terrestrial, not colder than Titan, and with a Nitrogen dominated atmosphere like Titan. Science often despairs about terrestrial planets around red dwarfs being stripped of atmosphere. But in the case of a planet sufficiently further away from its star, I think a favorable outcome could be likely. With less mass in its planet forming disc, the erosion of a Hycean atmosphere, to a Tital like atmosphere could be favored. If a star system were young it might have a far-out Hycean-Terrestrial, which could originally been a bit like a Mini-Neptune a first, and then the Hycean stage might be followed by a Titan-Like Terrestrial atmosphere. Such a world could have ice covered liquid oceans.

So, those who could go interstellar might have the small, presumably airless world close to Banards Star, and such a cold terrestrial or Hycean world, and perhaps some Dwarf Planets and some comets.

Ending Pending

Last edited by Void (2024-10-01 09:23:51)

Void · 2024-10-01 18:38:34

Anton Petrov has a better conversation about the Barnard b planet: https://www.youtube.com/watch?v=QMaCh38PjIY
Quote:

Exciting Planet Found Only 6 Light Years Away From Earth (Barnard's Star)
Anton Petrov
1.36M subscribers
Join
Subscribed

So, the planet would not be as hot as I thought on the sun side, maybe 125 C?

But too hot for life. Probably the planet does not have an atmosphere.

A best hope for life on such a world could be a ice covered sea on the dark side of the planet. I don't know if the solar flares would strip the ice on the dark side or not. But they might create water by bombarding the regolith on the day side with protons.

But these things are not known at this time.

Ending Pending

So, there said to be hints of 3 more smaller planets possible. The outer one would have a 6.7-day orbit, which would make it about 1/4 as hot on the day side as the one they are certain exists. I also would likely not have an atmosphere I expect, but it might be more likely to have icy deposits on a possible tidal locked night side or perhaps shadowed crater polar area.

I think that planets half as big as Venus or even smaller could be quite attractive for the idea of extracting mass to a solar orbit.

Ending Pending

Such planets could be heated by tidal forces or perhaps by solar flare inductive heating.

Ending Pending

Last edited by Void (2024-10-01 18:53:01)

Calliban · 2024-10-02 04:25:36

Probably too hot for life on the day side. But this world may turn out to be a viable target for human colonisation a few centuries hence. We would settle along the terminator line away from the solar glare. The day side would be a good place to establish concentrating solar power infrastructure for a global electric power grid. The permanently shielded night side may well be enriched with volatiles. All things considered, this might be a good place to settle, even if it isn't somewhere for life to evolve naturally.

One down side to settling red dwarf planets - these worlds are very close to their respective stars and very deep within its gravity well. So dV needed to escape the planet would be very high, on the order of hundreds of km/s. Rather like Hotel California, you can check out any time you like, but you can never leave.

Void · 2024-10-02 06:34:58

It can be hoped that such a solar system has Dwarf Planets much further out, as our solar system does.

Propulsive systems that could use the Solar Wind might be workable in that alien solar system.

Ending Pending

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