How did Edwin Hubble measure the distance to the Andromeda Galaxy?
A) He measured its parallax.
B) He applied the period-luminosity relation to Cepheid variables.
C) He deduced it from its redshift.
D) He used white dwarf supernovae.
Question 2
What use are 21 cm radio waves to Galactic astronomers?
A) They cut through the dusty cocoons to let us watch star birth.
B) We can reflect them off the core of the Galaxy.
C) Their Doppler shifts let us map the motions and locations of gas in the spiral arms.
D) They bounce off stars like our Sun to let us precisely measure their distances.
E) They pick up the cool, dark matter much better than can optical telescopes.
Local and long–distance cell communication in animals.
Closed urinary drainage system. Urine being measured after it leaves patient’s body via catheter.
Pulmonary function test: spirometry. (a) Normal respiratory volumes, as measured during spirometry.
Andromeda (M31)
Particles measured, 1970 - 2008 and Trend in Organic Compound 1990 - 2007
Finding the length given total distance and distance longer than other point