Examlex
Variable stars such as Cepheid variables are used in what important measurement in astronomy?
Q64: The energy-generation mechanism for active galaxies is
Q69: What is a "hypervelocity" star?<br>A) It is
Q97: What physical process has allowed astronomers to
Q97: The first 10<sup>-43</sup> s of the age
Q97: What happens to the density of an
Q103: The 21-cm line is one of the
Q149: A stellar core of about 2 solar
Q154: Cepheid variable stars are useful to astronomers
Q172: What is a rich cluster of galaxies?<br>A)
Q176: The Tully-Fisher relation provides a method of