In order to obtain a circular orbit, which direction does the initial velocity vector have to point?

Which measure of humidity, relative humidity or dew point, best describes the actual quantity of water vapor in a mass of air

What are the answers for the following questions?

Ascientist is explaining how background cosmic radiation gives evidence of the big bang theory. she says that radiation has been detected everywhere equally as heat in the universe and is increasing. this has been shown to be residual radiation from the big bang. what error did the scientist make?