# Tag Info

1

it might be more accurate to say that our solar system is to some extent a failed binary star system - as there are stars out there with exoplanets in the 'brown dwarf range' of mass - if our star system had enough mass initially to result in such an arrangement, there probably wouldn't be an earthlike planet around for us to exist on and see it up close, ...

10

The only stars you can reliably see are ones that are spewing enough photons at your eyeballs to appear stable. Any star which is so dim that photons entering your eye can literally be counted one by one, simply will not register in your vision, because your eye's retina is not sensitive enough. So your question is basically embroiled in observer bias; it ...

21

Although I agree with all three of the above answers let me present a slightly different perspective on the problem. It's tempting to think of the light from the star as a flood of photons that behave like little bullets. However this is oversimplified because a photon is a localised object i.e. we observe a photon when something interacts with the light ...

44

The answer is simple: Yes, stars really do produce that many photons. This calculation is a solid (though very rough) approximation that a star the size of the sun might emit about $10^{45}$ visible photons per second (1 followed by 45 zeros, a billion billion billion billion billion photons). You can do the calculation: If you're 10 light-years away from ...

7

Allow me to channel something akin to the anthropic principle here. You can only see the stars that have a lot of photons reaching your eye. If a star were so far away that photons were reaching your eyes only occasionally then the star would be too dim for you to see in in the first place. Even if you could see the photons, the star would appear to ...

5

A star radiates in all directions. You would still see the star regardless of the number of steps you take to any side, just not the same photons. A laser radiates in only one direction (or in a very small cone). If you took a large enough step to the side (larger than the angular size of the emitted beam) so as to exit this cone, then you would no longer ...

1

The Iridium satellites can be easily seen naked eyes. They also have flares that permit to see them even easier. This is when the flares will happen and daily predictions for all brighter satellites.

0

Just to expand on the stars->gold thing. The lightest elements (hydrogen, helium, deuterium, lithium) were produced in the Big Bang nucleosynthesis. The temperatures in the early universe were so high that fusion reactions could take place. Nuclear fusion in stars converts hydrogen into helium in all stars. More massive stars have further reactions that ...

5

Gravity is not needed in any way (it only helps to increase the pressure inside the stars but the pressure may be "mimicked" in other ways) and the energy needed for these transmutations isn't extremely high. It's just the nuclear energy conditions. See https://en.wikipedia.org/wiki/Synthesis_of_precious_metals Consequently, one may produce gold in ...

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