Most recent answer: 06/13/2015
- Elias DeJesus (age 19)
1) Do photons lose energy over the course of distance they traveled?
They do because of the expansion of space. The wavelength gets strecthed out and the frequency reduced.
do they lose energy when they interact with matter?
#2) How far is the temperature of space from absolute zero?
It's currently 2.725 K, in between the temperature of superfluid liquid helium and ordinary liquid helium.
#3) Will the universe continue to expand to reach absolute zero before the force of gravity can no longer compensate the expansion of space?
Ordinary gravity is already too weak to slow the expansion. The mysterious "dark energy" is accelerating the expansion. Unless something fundamental changes, the expansion will continue forever, leaving a very cold, empty universe.
#4) When compared to the electromagnetic spectrum, how small or large is the visible spectrum?
The visible spectrum covers about one factor of 2 in frequency. The electromagnetic spectrum covers a range of at least about 130 factors of 2, from the frequency at which it merges into the unified electroweak force down to the inverse of the lifetime of the universe.
#5) Last question! What are beyond gamma rays on the electromagnetic spectrum?
Does the name matter? It's all just EM waves up to the electroweak unification scale.
(published on 06/13/2015)