Small words please

[unclehobart]

I'm trying to patch it together from old memories. I used to have all of this interstellar physics down pat. Not having used it in a while has fuzzed the details.

I actually believe that an Earth mass the size of a basketball would have actually strong gravity at 100 feet. It should actually have Earth-like gravity going out a good distance. I need to look it up... when I get time.

 

[chcr]

I'm trying to patch it together from old memories. I used to have all of this interstellar physics down pat. Not having used it in a while has fuzzed the details.

I actually believe that an Earth mass the size of a basketball would have actually strong gravity at 100 feet. It should actually have Earth-like gravity going out a good distance. I need to look it up... when I get time.

There's a formula to calculate it. I can't remember what it is and don't have time to hunt for it now, but you certainly could be right. I was guessing. It decreases pretty rapidly as a function of distance in any case. If I have time after the gym and making dinner I'll see if I can find it. Gravity is actually by far the "weakest" of the physical forces. I always think that's a little counter-intuitive myself. It's just that the distances and volumes are so small for the strong and weak atomic forces.

 

[chcr]

Never mind unc, I'm an idjit. You calculate the acceleration of gravity from the center of mass, just as you said. I don't know why I was thinking that it was from the surface. However, if you could magically go to the center of the mass, the force of gravity would be equal in all directions so you would be effectively weightless. Actually, I think where I confused myself was remembering that in college I had to calculate how gravity would change as you tunneled toward the center of the earth. My physics prof was a hoot.