Alien life could thrive on big 'Hycean' exoplanets

[Admin]

The search for alien life should broaden its horizons a bit, a new study suggests.

Alien life could thrive on big 'Hycean' exoplanets : Read more

 

[Catastrophe]

"Alien hunters have to date focused largely on Earthlike planets — a reasonable place to start, given that our rocky, water-covered world is the only one we know of that hosts life. But the universe teems with a huge diversity of planets, some of which may be habitable despite being decidedly un-Earthlike."

Cat

 

[rod]

"Hycean planets are up to 2.5 times bigger than Earth, with oceans and hydrogen-rich atmospheres."

Interesting report. This exoplanet site shows 1319 exoplanets with radii <=2 earth radii, The Extrasolar Planets Encyclopaedia (exoplanet.eu) Their distances from the parent stars range 0.0034 au to 1.98 au distance (semimajor axis). This exoplanet site shows 1310 with similar distances, 0.0058 au to 1.046 au, https://exoplanetarchive.ipac.caltech.edu/index.html

It would be good to see which exoplanets are confirmed as *Hycean* types. Abiogenesis is assumed to take place all over in the galaxy now it seems. In the 1990s, meteorite ALH84001 was reported to contain little Martians but problems arose.

 

[Joojoo]

Hi, I'm new here.
This article interested me and I wanted to seek opinion on this statement:

Habitable hycean worlds, in contrast, could be found anywhere from as close to a Sun-like star as the orbit of Venus to as far out as, well, anywhere — even outside a star system.
“They can be free-floating planets,” Madhusudhan says, their insulating hydrogen atmospheres preserving habitable conditions even in the vast darkness of interstellar space.

Can someone explain this to me? I understand that the Hydrogen atmosphere may be a very good insulator, but claims about how far out these planets can be whilst maintaining liquid water seem a little exagerrated. At some point even the Hydrogen would become solid, without some heat source. Is the solid core of the planet assumed to hold heat, like on Earth?

In reality, how far out do you think the orbit could be whilst maintaining liquid water from solar irradiation alone? (For example using a sun like our own)

Sorry if this is a stupid question.

 

[rod]

Joojoo, my opinion. The habitable hycean exoplanets looks like a model interpretation that is seeking to find such exoplanets, including life on them. This is a model interpretation not confirmed by the scientific method based upon observations in nature showing the model describes actual reality. When Galileo argued against the geocentric teachers, Galileo could show them the tiny lights moving around Jupiter, again, and again.

 

[Joojoo]

Thanks Rod.

Yeah I understand that, it's interesting just to know that there's another type of planet out there that they believe could support life, and that existing methods of looking for life (atmosphere anaysis) will work better on these types than on earth type planets (with the caveat that they have nothing to compare to).

I was just struck by how far out from the sun liquid water may exist.

 

[rod]

FYI. I dug more into hycean worlds. Other reports are out on this now too. New class of habitable exoplanets represent a big step forward in the search for life, https://phys.org/news/2021-08-class-habitable-exoplanets-big-life.html

This report discusses the exoplanet K2-18 b as a possible example. The Extrasolar Planet Encyclopaedia — K2-18 b (exoplanet.eu)

The reported calculated temperature is 284 K. Radius near 2.37 earth radii and mass about 8.92 earth masses. It orbits very close to the red dwarf star with large eccentricity, some 0.20 reported and distance some 38 pc. Showing exoplanets like this are habitable and have life I feel has some more work to confirm. The mean density of K2-18 b is near 3.7 g cm^-3.