How do we know that pulsars are neutron stars?
A) We have observed massive-star supernovae produce pulsars.
B) Pulsars and neutron stars look exactly the same.
C) No massive object, other than a neutron star, could spin as fast as we observe pulsars spin.
D) Pulsars have the same upper mass limit as neutron stars do.
E) none of the above
Question 2
Masses of the planets are easiest to determine if:
A) they are terrestrial and the extra size of the planet's disk can be measured.
B) they are jovian and their oblateness can be found.
C) they have natural satellites whose motions can be precisely measured.
D) they are dense and easily deflect the path of passing spacecraft.
E) they move rapidly and their periods are easily measured.
Body plan of an echinoderm, as represented by a sea star.
Betelgeuse is a semiregular variable star
Stars vary widely in size.
A Binary Star System
A Summary of the Star Formation Process