[davisfh]

If Gliese has a composition similar to earth and is 3.1 to 4.3 times the mass of Earth, the gravity would be pretty enormous. If so, it would be very difficult for humans to exist there. There might be some human-like creatures there who would be much like Superman to us. I also assume that the term “mass” used here means just that.

[Dallas59]

They may be very small and lightweight...

[BenKenobi]

Depends on the rock density. Surface gravity is a function of the radius of the planet.

[3niner]

Mass/gravity relationships are not quite that simple. If a planet, 4 times the mass of Earth, were the same density as Earth, it would also be larger. This means that someone standing on the surface would be further from the center of mass, partially compensating for the increase in mass.

It has been many, many years since I've done these kinds of calculations, but I believe the difference in surface gravity would be a factor of the cube root of 4 (about 1.6). This would be heavy gravity for a human, but would allow for walking about.

Of course, the other planet might be denser, the temperature might be much higher or lower (even if it is in the "Goldilocks Zone"), and the atmosphere could be very different. The biggest difficulty, however, would be in getting there to take a stroll on it.

[Seven plus One]

There might be some human-like creatures there who would be much like Superman to us. I also assume that the term “mass” used here means just that.

It probably means just the opposite.

[freekitty]

Obama thinks he is superman. Let’s send him there.