1
vote
2answers
192 views

Light formed by the sun?

This is an extract from the astrophysics chapter in my book: Hydrogen atoms fuse to form helium. At the same time, lots of of gamma photons and neutrinos are produced. The photons take thousands ...
8
votes
2answers
1k views

Do photons lose energy while travelling through space? Or why are planets closer to the sun warmer?

My train of thought was the following: The Earth orbiting the Sun is at times 5 million kilometers closer to it than others, but this is almost irrelevant to the seasons. Instead, the temperature ...
6
votes
3answers
667 views

How many percent of the visible light reaching the Earth are from other stars than the Sun?

How many percent of the whole visible light reaching the Earth are from other stars than the Sun? Is it maybe 0,5 - 1% or is my guess already too much? I am interested mainly in visible light, but ...
4
votes
1answer
285 views

Photons arriving from the Sun

Given that the Sun is a bit less than 10 light minutes away from Earth, is it correct to assume in principle (I understand actual processes in the core of the Sun make the situation at a photon's ...
-4
votes
1answer
103 views

Black out the sun?

How many observers would it take to cancel out the number of photons produced in a medium sized star like our Sun, thus making it dark? (I want to consume more photons than the star is generating)
0
votes
1answer
156 views

Exist some relationship between irradiance units and wavelenght of the incident sunlight?

Exist some relationship between irradiance units and wavelength of the incident sunlight? What about irradiance? I want to establish a relationship between wavelength and irradiance, because I would ...
3
votes
1answer
254 views

If 100% of the energy from the sun is reflected back into space

100% of the energy from the sun is reflected back into space, it's just shifted from a low-entropy state to a high-entropy state, and from a high frequency (ultraviolet) to a low frequency (infrared). ...