If we imagine that 1 in 10 million stars would eventually give rise to a civilization on an orbiting planet and assuming that there are 100 billion stars in our Milky Way galaxy, how often should a civilization randomly appear over a 5 billion year
period? A) once every 50 million years
B) once every 50,000 years
C) once every 500,000 years
D) once every 5 million years
Question 2
Rayleigh scattering would have 400. nm light be scattered how many times as much as 800. nm light?
A) 32
B) 4
C) 8
D) 2
E) 16
The two bright stars are (left) Alpha Centauri and (right) Beta Centauri.
Sunlight shining through clouds, giving rise to crepuscular rays.
The Types of Stars and Their Sizes
Luna Park at Coney Island was a vast living theater in which strollers were both spectators and acto
When young infants hold objects for a long period of time they eventually become habituated to them.
Sea-Level Rise