Process of Science: The theory of spiral arms explain why short-lived, massive stars are found there but longer-lived, low mass stars should last for many orbits around a galaxy and therefore be much more spread out.
How might you test that prediction?
Question 2
Suppose the planet Uranus were much brighter in the sky, so that it was as easily visible to the naked eye as Jupiter or Saturn. Which one of the following statements would most likely be true in that case?
A) Its brightness would make it possible to read by starlight at night.
B) Its gravity would cause the tides to be much higher than they actually are.
C) Its slow motion through the sky would have led it to be named after the Goddess of Procrastination.
D) The discovery that Earth is a planet going around the Sun would have come hundreds of years earlier.
E) A week would have eight days instead of seven, despite the year length being unchanged.