The nearest star system to our Sun, Alpha Centauri, is still over a parsec distant.
Indicate whether the statement is true or false
Question 2
How was Edwin Hubble able to use his discovery of Cepheids in Andromeda to prove that the spiral nebulae were actually galaxies external to the Milky Way?
A) From the period-luminosity relation for Cepheids, he was able to determine the distance to Andromeda. He showed that it was far outside the Milky Way Galaxy.
B) He used main-sequence fitting to determine the distances to the Cepheids. He showed that Andromeda was far outside the Milky Way Galaxy.
C) There are no Cepheids in the Milky Way, so his discovery proved that Andromeda had to be in another galaxy.
D) As a Cepheid is a type of luminous galaxy, Hubble's discovery of Cepheids in Andromeda proved that it was a separate galaxy from the Milky Way.
E) He measured the parallaxes of the Cepheids in Andromeda to determine their distances. He showed that Andromeda was far outside the Milky Way Galaxy.
Three Chamber Heart -- Circulatory System
Renal System
Monstrous people from distant lands depicted in a fifteenth-century European woodcut.
Testing distant vision
Male Reproductive System - Testes
Male Reproductive System - Testes ذكر الجهاز التناسلي - الخصيتين