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Science

longship

(40,416 posts)

6. Well, mass isn't the only factor.

Reply to Warpy (Reply #5)

Thu Dec 17, 2015, 08:40 PM

Dec 2015

Gravity is proportional to mass, but inversely proportional to the radius-squared. So size is more important than mass.

We need to know either this planet's size or its density, which will give us its size.

Then, we will know its surface gravity.

At 5.21 times Earth mass, it would only have to have a radius of about 2.3 times that of the Earth to have the exact same gravity as the Earth. That is how the math works out.

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Highlight:

Nearby star hosts closest alien planet in the 'habitable zone' [View all] Matthew28 Dec 2015 OP

Wonder how old the system is? That can mean a lot. BlueJazz Dec 2015 #1

Four times the mass of Earth? Not so fast Warpy Dec 2015 #3

Actually, 5.21 times Earth mass. nt longship Dec 2015 #4

Worser and worser Warpy Dec 2015 #5

Well, mass isn't the only factor. longship Dec 2015 #6

That is the third planet Matthew28 Dec 2015 #7

Okay, I got it. 4.25 Earth masses. longship Dec 2015 #9

A few problems with this one. longship Dec 2015 #2

Here is the the information Matthew28 Dec 2015 #8

Here is some other close possible habitual planets Matthew28 Dec 2015 #10

On the Composition of Wolf 1061c ThomasTarrants Dec 2015 #11