# Got an astrophysics/ astrodynamics question...

#### Oracle1

How would a solar system need to be set up to provide a life bearing world, standard 1 g, with the surface area of Jupiter with a standard day / night 24 hour cycle?

Related Writing and World Building News on Phys.org

#### phinds

Gold Member
How would a solar system need to be set up to provide a life bearing world, standard 1 g, with the surface area of Jupiter with a standard day / night 24 hour cycle?
I think that would work if the Earth were the size of Jupiter and made of styrofoam. Since it's mass, not diameter, that determines orbit, the Earth would have the same orbital period and with the mass the same as Earth, but being made of styrofoam (approximately) it would have the surface area of Jupiter.

Of course, it's hard to figure how you could have a planet made of styrofoam or any equivalently weighted matter.

#### Oracle1

What about outside celestial influences creating a constant counter gravitational effect?

All the mass but the desired gravity.

#### phinds

Gold Member
What about outside celestial influences creating a constant counter gravitational effect?

All the mass but the desired gravity.
OOPS. I forgot to state that of course the gravity on the surface of the styrofoam planet would be way less than on Earth because same mass but much greater diameter

#### Oracle1

Thanks! But darn it, I'm going to have to figure something out! I need this planet to have standard mass and gravity. (though the thought of a Styrofoam planet is amusing.)

I don't really want to Sci Fi this. I'm going to be bending just about every other rule into a pretzel for this story.

My thinking is: if space is infinite with the possibility of infinite variety, then there must be some version of a solar system that could support a planet like this.

I just wanted... NEEDED really, some help figuring out how to set it up.

#### phinds

Gold Member
My thinking is: if space is infinite with the possibility of infinite variety, then there must be some version of a solar system that could support a planet like this.
Learn the math of planetary orbits and figure out if one is possible, but a surface the size of Jupiter but gravity same as Earth is going to mean a styrofoam (or equivalent) planet. Period.

#### Oracle1

Well, That seems to put that idea to rest. Thanks for the feedback phinds.

"Got an astrophysics/ astrodynamics question..."

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving