I’m an astrophysicist and my research is mainly concerned with what may be called the “time domain universe”, or simply: stars whose brightness varies with time.
Stars can have a variable brightness for one of several reasons: they might be intrinsically variable due to pulsations of the star’s atmosphere; they might be in orbit with another object that periodically passes in front of it; or they might suffer some form of catastrophic change that causes flaring or outburst behaviour, for instance.
One way to carry out research in time domain astrophysics is simply to monitor the brightness of all the stars in the sky and see what you find. This is, in effect, what is done by the WASP (Wide Angle Search for Planets) project, of which I and others at the Open University are part.