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3. A ____ is a type of neutron star which has strong magnetic fields, spins rapidly and emits beams of radio waves along its magnetic axis.
5. ________ are invisible surfaces around stars in a binary system which represent the points where the gravitational potential of both stars is equal.
7. This element is absent from the observed spectra of type 1a supernovae.
8. At the LIGO, there are two enormous _____ interferometers which is used to detect gravitational waves.
11. The ____ limit describes the maximum mass a white dwarf can have before collapsing.
13. _____ detection is a method that uses the gravitational influence of the black hole on nearby stars to detect their presence. This is a novel detection method.

1. ______ is the curvature of space-time.
2. These are explosions of stars.
4. A ___ is a type of neutron star with an extremely powerful magnetic field.
6. _____ degeneracy is a crucial concept in maintaining the white dwarf.
9. Since the surface gravity of a neutron star is millions of times greater than the surface gravity of the Earth, a tremendous weight causes the crust of the star to shift and contract to cause a ____.
10. While X-ray astronomy can locate potential black hole candidates, ____ needs to be also determined to make a strong case as to whether this compact object is a black hole or not.
12. The ______ exclusion principle helps to explain electron degeneracy in white dwarfs.