Cepheid variables can be used to determine distances because their _____________ can be determined from their _____________
Fill in the blank(s) with correct word
absolute magnitude
period
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Which terrestrial planets lack seasons? Why?
What will be an ideal response?
A distinctive feature of quarks is that they
A) are always observed singly, since they do not readily interact with other particles. B) have zero charge. C) have zero rest mass. D) have fractional electric charge.
What is the ultimate fate of an isolated pulsar (not in a binary system)?
A) It will spin ever faster, becoming a millisecond pulsar. B) As gravity overwhelms the neutron degeneracy pressure, it will explode as a supernova. C) As gravity overwhelms the neutron degeneracy pressure, it will become a white dwarf. D) It will gradually cool, and it will become too dim to detect. E) It will gradually turn into a white dwarf.
) A vertically oriented rocket that is able to sustain a continuous upward velocity of 8 km/s will
A) escape from Earth. B) be unable to escape Earth. C) eventually maintain a fixed orbit around Earth.