天体距离的测量（小结） nearby galaxies (10y) Milky Way (105y) nearby stars (102y) solar system (10-4y) white-dwarf Venus supernovae Sun radar ranging period surface temperature parallax FIGURE 19.22 Measurement of cosmic main-sequence Tully-Fisher distances relies on a chain of interlocking techniques. fitting relation The chain begins with radar ranging to determine distances within our Cepheids solar system and proceeds through parallax and standard candle techniques to distant Hubble's Law.which provides distances to galaxies across the observable universe. standards