Hi there.

So to figure out these I am going to do a little calculation:

Fource of gravity = G*M*m/r^2, where G is a constant, M is the mass of the planet, m is another object, and r is how far you are form the center of the object (so the radius of the planet if you are on its surface).

So if you are interested in how much the gravity would be compared to Earth you would have

F_mars/F_Earth=(G*M_mars*m/R_mars^2 ) / (G*M_earth*m/R_earth^2 )= M_Mars/M_Earth *(R_earth/R_Mars)^2

So, from http://nineplanets.org/ I have

M_mars= 6.4219e23 kg M_earth=5.972e24 kg R_Mars=3397 km R_Earth=6378 km

The format with the "e" (1e6 for instance) is a short hand way of saying that there should be that number of zeros after the number. So, 1e6=1,000,000.

So the force of gravity is lower on Mars than Earth by a factor of ( 6.4219e23/5.972e2) *( 6378/3397)^2 = 0.38

For Mars's moons you can do a similar calculation. They are not very round which makes it a little more complicated, but you can get in the ball park:

For Phobos R=11km M=1.08e16 kg, so gravity is 0.0006 times that of eart

For Demos R=6 km M=1.80e15 kg so I get that the gravity to be 0.00034 times that of Earth. You'd have to work mot to float away!

Phobos 9 11 1.08e16 Hall 1877 Deimos 23 6 1.80e15

Read more about Mars l Mars facts, pictures and information. by nineplanets.org

You might be interested in this web page: http://www.exploratorium.edu/ronh/weight/

The speed of light is about 300,000 km/s. The distance to Mars is about 227,940,000 km, so the time light needs to get from the Sun to Mars is

227,940,000 km/ 300,000 km/s.=759.80 seconds = just under 13 minutes

Cheers,

Terry