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
President-elect Barack Obama 150 million tiny carbon nanotubes
A mound of buffalo skulls. In 1870 an estimated 30 million buffalo roamed the plains; by 1900 there
When young infants hold objects for a long period of time they eventually become habituated to them.
Will the sun rise tomorrow? Are you sure? “Cause and effect” vs. sense experience.
The human eye, a product of 600 million years of evolution (Lamb, Collin, & Pugh, 2007).
Rising sea level: Some areas will be affected by a rise of just 40 cm