How much force would Superman need to hold back the moon at half a G-force?

  • Level: Undergrad 
  • Thread starter Thread starter randy23
  • Start date Start date
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
8 replies · 4K views
randy23
Messages
14
Reaction score
0
I'm a comic fan especially Superman and one of his feats dealt with him holding the moon that was supposedly increasing in momentum at fraction of a G-Force. My question is: is that really an impressive feat? A fraction of a G-Force? If it was half of a G-Force, how much force would he holding back against the moon to keep it stationary?
 
Astronomy news on Phys.org
The question isn't too clear, momentum isn't measured in units of force or acceleration...are you saying that if Superman wasn't pushing back, the moon would be accelerating at 0.5G? Because the moon is so massive, the force needed to get it to accelerate like that would be pretty huge (just multiply the moon's mass by an acceleration of 0.5G), and the force needed to push back and prevent the moon from accelerating would need to be the same size.
 
JesseM said:
The question isn't too clear, momentum isn't measured in units of force or acceleration...are you saying that if Superman wasn't pushing back, the moon would be accelerating at 0.5G? Because the moon is so massive, the force needed to get it to accelerate like that would be pretty huge (just multiply the moon's mass by an acceleration of 0.5G), and the force needed to push back and prevent the moon from accelerating would need to be the same size.

Well I'm not sure about the momentum. DC is pretty much based on pseudo-science but I just wanted to know using real sciences. Thank you for the insightful reply.
 
For some numbers, the amount of force needed to accelerate the Moon at .5g would be about the same as what it would take to hold up a 80,000,000,000,000,000,000,000 lb weight on the surface of the Earth.
 
Janus, thanks for the calculations. How did you go about calculating that number?
 
The Moon has A mass of 7.35 x 1022 Kilograms
A mass of one kilogram weighs 2.2 lbs on the surface of the Earth at 1g.
The same kilogram would weigh half as much at 0.5g or 1.1lb.
1.1lb/kg x 7.35 x 1022 kg = 8 x 1022lbs
 
Thanks. But the fraction of g-force they commented about could also mean .000000001, right?
 
randy23 said:
Thanks. But the fraction of g-force they commented about could also mean .000000001, right?

Okay, then the weight would be 160,000,000,000,000 lbs. (about equal to the weight of 10 billion African Bull elephants)
 
Why would Superman want to tinker with the Moon? It's fine where it is.
If Superman were pushing hard enough on the Moon for it to have any significant impact, he would probably push through the Moon instead. If 10 billion African Bull elephants had their mass compacted into the size of Superman I doubt the surface of the Moon could support it. Superman would quickly find himself at the core of the Moon. But that would be cool because he could tell us what it is made of. I know the surface is Swiss, but I believe scientists theorize that the core is Cheddar.