These thrusters will produce a force roughly the same as whispering in somebody's ear which should be just enough to keep the two spacecraft moving at a relative velocity of less than 20 microns a second.

ECONOMIST: Birds of a feather

Radar measurements are incredibly accurate: we get the distance to the asteroid very, very precisely, and we can also get its velocity relative to us.

BBC: Apophis asteroid: Large space rock flies past Earth

Given this, how are the newest smart marketing people dealing with the volume and velocity of data and using it to gain insight relative to what consumers want and need?

FORBES: How IBM Helped "X Factor" Up Its Ratings

The theory explained that space is relative and not constant, and the only thing that is constant is the velocity of light.

UNESCO: Culture

For such a particle, it is possible to work out its velocity (from the time taken to pass between the two layers) and its trajectory (from the relative positions of the elements triggered in each sensor layer).

ECONOMIST: Orbital debris