An individual who wants others to pay for public goods, but plans to use those goods for their own purposes, is often referred to as a _____________________.  

The initial mass of a protostar generally determines the star’s future evolution. But in some cases, what can alter this process?

What use are 21-cm radio waves to galactic astronomers?

What is one of the differences between Cepheids and RR Lyrae variables?

A proposed explanation for gamma-ray bursters is

Most pulsars are observed only as ________ sources.

What can you conclude about a Type I supernova?

While featureless in visible light, we can see some detail in Venus’ clouds using

The surface of Europa is most like the Earth’s

What is true of Mars?