Is there Earth like planets the size of Jupiter?

I was wondering if it was possible for there to be a planet the size of Jupiter but habitable like the earth?

I dont think we have found any planet that large that was not a Gas Giant yet but its a big universe.

I dont seen any reason why that would be impossible. I dont think we know enough about planets to rule something like that out since we have only recently detected what is surely the smallest fraction of whats outside our solar system.

Originally posted by thecry
I was wondering if it was possible for there to be a planet the size of Jupiter but habitable like the earth?

I don't see why not, although, like Shadow, I don't think we've found any yet. One issue with such a large earthlike planet would be gravity, though. A gas giant's volume is mostly gas (duh!) which means between an earthlike planet and a gas giant of the same size, the earthlike one would have a much higher gravitational field. Life might still be able to inhabit such a world, but humans would suffocate under their own weight on such a world.

If it has the right mass and gravity all seems to be possible. Could you imagine a world with 100 Billion people/humans?.....

Sign me up and beem me up Scotty

I seen a show that tried to invision what alien creatures might look like if they evolved on a planet with much greater gravity then earth.They came up with a creature with many thick legs like elephant and very low to the ground.

It was pretty interesting, One thing for sure if a alien could lived on a planet like that if it came to earth it would have some serious ups here

I'd imagine life on a gas giant would live in the atmosphere. Flying creatures whose bodies are less dense that the gasses that exist on the lower levels, close to the surface. Maybe jellyfish looking things. And they breath fire, because they're my creatures and I want them to.

Doesn't the gravity depend on how fast the planet spins rather then the size? So if the Jupiter sized Earth spun at a certain rate wouldn't the gravity be the same? just curious...

I think its a combination of both speed (spin) and mass for gravity. All mass has gravitational attraction.

Venus I believe barely spins 243 Earth Days per rotation and has plenty of gravity

Well not quite the size of Jupiter, but large rocky planets have been detected. For example 55 Cancri E, a rocky planet roughly 14 times the mass of Earth. Current speculation is divided between two theories: either it was the rocky core of a gas giant, stripped of it's atmosphere when it got to close to it's star; or that it formed much like the rocky planets in our own solar system, just with a greater abundance of material. There is also the possibility that it may just be a small gas giant, but current observations seem to make that appear unlikely.

It's certainly a theoretical possibility though that some gas giants lose their atmospheres due to poximity with their stars, these are called Cthonian planets and would be very massive indeed.

[edit on 9/28/05 by xmotex]

gravity has absolutly nothing to do with the spining of a planet im pretty sure

how big could a planet as dense as the earth get before its own weight started to pose a problem in keeping its surface out? like is there a point where it would collapse as old stars do?

Such a planet might be inhabitable, but not by humans. Jupiter is a lot less dense than Earth, and its surface gravity (insomuch as it has a definable "surface") is 2.54G. A rocky planet that size would have SIGNIFICANTLY more gravity, probably well over 4G or maybe much higher. No humans could live like that long term, unless we invent some cool gravity cancelling technology.

I can't imagine anything like 'earth like' life forming on such a planet with that much gravity, heck the gravity'd be much stronger than on jupiter even because the planet has more mass too. Perhaps there could be weirdly stable chemical reactions and the like, but probably not even cellular life. But here are some interesting papers:
GROUND-BASED MODELS FOR STUDYING ADAPTATION TO ALTERED GRAVITY ... (doc)
Gravity shapes life (pdf)

Haven't looked at them tho.

1. Gravity has nothing to do with how fast a planet is spinning. It's a function of mass. Your attraction to the planet (and the planet's attraction to you, no matter how infinitesimal). You are attracted the the planet's center of mass, and the attraction decreases geometrically the further you get from the planet's center of mass.

2. Gas Giants are largely liquid/gas. You may remember from high school that temperature varies with pressure and volume. What this means is, the gravity on Jupiter is so high, that atmospheric gasses (mostly methane) are under such pressure that they are liquified. So, because a planet the size of jupiter is SO BIG, it will liquify it's own atmosphere and even it's metalliod core. So, way too hot and pressurized to be "earth-like." mars would be a lot closer.

3. In the classic 80's series "Cosmos," Astronomer Carl Sagan speculated about life forms that might be possible in the upper atmosphere of Jupiter. Even commissioned some paintings of them. [I still have an autographed copy of the companion book]. Extraterrestial life had been Sagan's specialty back in the 60's, and hit was he and Drake who did the original calculation of the possibility of intelligent life on other worlds.

Incidentally, the Hubble telescope refuted the suppositions of Sagan's calculations, showing them off by several orders of magnitude, and also implying that the known universe is statistically unlikely to have another civilization capable of communicating by radio-wave electromagnetism OR spacefaring.

Originally posted by dr_strangecraft



3. In the classic 80's series "Cosmos," Astronomer Carl Sagan speculated about life forms that might be possible in the upper atmosphere of Jupiter. Even commissioned some paintings of them.

Floaters and Hunters There is now a "Cosmos" show with Carl Sagan on the discovery science channel with all redone animations.

Check your local listings

Originally posted by ShadowXIX
There is now a "Cosmos" show with Carl Sagan on the discovery science channel with all redone animations.

Check your local listings

I wonder whether they updated the science any. I wrote a blog on here last year about the "probability of galactic civilization equation" and how most "UFO hopefuls" aren't aware they are pinning their dreams on antiquated theory for the myriad "must be life out there" posts.

Anyway. Learning about the results from Hubble (the telescope, not the politician!) really affected by cosmology.

Gravity is dependant of the mass of two objects and thier distance.. Has NOTHING to do with spin

If Jupiter was not a gas giant, but a rocky planet, its mass would be much higher that it would be almsot impossible for humans to live on the surface. Unless that planet was made out of light metals and thus the mass of the planet reduced.

WHat would be more ideal would be to take taht mass, give it spin, and turn it into a miniture dyson's sphere