What word is used to describe knowledge about the universe and the method of obtaining that knowledge?

Because light travels in a straight line and casts a shadow, isaac newton hypothesized that light is

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?

Name two kinds of practical electric pumps.