Transcript: Since light has a finite speed, three hundred thousand kilometers per second, there’s an inevitable consequence called light travel time. In terrestrial environments light essentially travels instantly or appears to travel fast. The finite speed of light, three hundred thousand...

Transcript: Some stars in the sky, somewhat hotter than the Sun with temperatures of 5 thousand to 10 thousand Kelvin, have very low luminosities in the range of one-hundredth to one-thousandth the Sun’s luminosity. Application of the Stephan-Boltzmann Law shows that they must be physically...

Transcript: Certain rare stars in the sky with either red or blue colors are extremely luminous, up to a million times the luminosity of the Sun. Application of the Stephan-Boltzmann Law shows that their sizes must be in the range of ten to a thousand times the size of the Sun. These...