The ________ is the observational evidence that the whole universe was once extremely hot and dense, as called for in the Big Bang, but has now expanded and redshifted this energy to much longer wavelengths.
Fill in the blank(s) with correct word
Question 2
Thermal radiation is defined as
A) radiation produced by a hot object.
B) radiation in the infrared part of the spectrum.
C) radiation that depends only on the emitting object's temperature.
D) radiation in the form of emission lines from an object.
E) radiation that is felt as heat.