No it does not. The more mass an object has, the more gravity it has. Saturn has little gravity because it's made of gas. However Jupiter has immense gravity due to it's incredible mass. A rock floating through space would attract things, as long as these objects are less in mass than the rock. This also depends on the speed of the two objects. If a speck of dust and the rock were completely immobile (impossible though) the speck would eventually collide with the rock. However if the speck of dust is going fast enough and with enough force it will escape the rocks gravitational pull. But you also have to take into account the effect of other planets nearby and asteroids etc. effecting the speck's movement also. Say a speck of dust was 3 mm away from a 3' diameter rock. However a planet of the mass of Earth was 3,000,000 miles away from the speck of dust, then the speck would be pulled towards the planet and be incinerated by Earth's atmosphere.
That's how gravity works, my friends.
As for ghosts. Hell no.
As for Aliens. Hell yes. Somewhere out there there are beings either animals, or dominant beings either ahead or behind us.