Yeah, any mass will work, say for example, you have an object that's 1kg, with an object of negligible mass orbiting it at a distance of 1 meter

http://en.wikipedia.org/wiki/Orbital_periodT = 2*pi* sqrt(a

^{3}/GM)

a = orbit's semi-major axis = 1m

G = gravitational constant = 6.674 * 10

^{-11} m

^{3} kg

^{-1} s

^{-2}.

M = mass of the object = 1kg

T = 2 * pi * sqrt(1m

^{3} / ( 6.674 * 10

^{-11} m

^{3} kg

^{-1} s

^{-2} * 1kg )

T = 2 * pi * sqrt(1m

^{3} / 6.674 * 10

^{-11} m

^{3} s

^{-2})

T = 2 * pi * sqrt(1.498*10

^{10} s

^{2})

T = 2 * pi * 122407 s

T = 769107s

T = 8.9 days.

So, if you had a 1kg mass, an another object of negligible mass was orbiting it in a circular orbit of 1m, it would take about 8.9 days for it to make a complete orbit. And since it's going a distance of 1m * 2 * pi = 6.283m. It would have an orbital velocity of 6.283m/769107s, or 8.169*10

^{-6}m/s. Or 8.169μm/s. So. if you had an object of negligible mass, 1m from a 1kg object, and gave it a push to the side, giving it a velocity of 8.169μm/s, it would orbit the 1kg object, in a circular orbit, taking about 8.9 days to make an orbit.

If you want to take the orbitting mass into account, which you probably should for things this small, you can just add the masses together to get the orbital period. Say for example you have 2 people, each 100kg, and you want to make them orbit, in a circular orbit around their common center of gravity, at a distance of 3m (just out of reach of each other.

)

a = orbit's semi-major axis = 3m

G = gravitational constant = 6.674 * 10

^{-11} m

^{3} kg

^{-1} s

^{-2}.

M = mass of the object = 200kg

T = 2 * pi * sqrt(3m

^{3} / ( 6.674 * 10

^{-11} m

^{3} kg

^{-1} s

^{-2} * 200kg )

T = 2 * pi * sqrt(3m

^{3} / 1.3348 * 10

^{-8} m

^{3} s

^{-2})

T = 2 * pi * sqrt(2.247*10

^{8} s

^{2})

T = 2 * pi * 14990 s

T = 94185s

T = 1.09 days

3m * 2pi = 18.85m

18.85m/94185s = .0002m/s = 0.2mm/s

So, if you had 2 100kg people, 3m apart, give one of them (or both of them?) a slight tap to the side to send them floating at 0.2mm/s, and they'd end up in a circular orbit around their center of mass, returning back to their starting points every 26 hours or so (also assuming that they're spherically symmetrical

)

See also

http://en.wikipedia.org/wiki/Escape_velocity For the maximum speed an object can have at a certain distance, from an object of a certain mass, and still be in orbit of it, more than that, and it would just keep moving away.