3 ms·

There must be a calculable limit to the size of the event that you can see at a given distance. There are finite number of photons which are emitted from an eve

There must be a calculable limit to the size of the event that you can see at a given distance. There are finite number of photons which are emitted from an event, these spread out with the inverse square law, so as your distance increases the probability of collecting sufficient photos to reconstruct an image of the event decreases and I would think at a distance of one lightyear it would be guess hard to see something much dimmer than an atom bomb.

hasenj 15y ago
But light travels as a wave, and my humble (and possibly mistaken) understanding (or conjecture) is that photons are nothing but particle-like manifestations of whatever thing light is "really" made of. Waves travel in all directions, they get weaker over long distances, but it's not as though some photon particles reach us while others don't. (or is it?) I mean, if light is just photon particles, then we'd have to be really lucky to see that many starts that are billions of light years away. Of course, I could be totally wrong!
- wtallis 15y ago
  Light travels as both a wave and as particles. Whether you observe light to behave as mostly particle-like or mostly wave-like depends on the circumstances. When you are dealing with very small intensities, you usually observe mostly particle-like behavior (but wave-like behavior still shows up in things like self-interference as demonstrated by the two-slit experiment). If you think that it's unlikely for a photon from a distant star to reach us, then you are simply vastly underestimating the number of photons involved. Consider by analogy the process of smelling something: actual molecules need to fly off the object, travel through the air, and impact your nasal passages in order for you to smell it. That means that anything you smell is constantly dispersing its mass into the atmosphere, but an object can remain pungent for a long time without significant weight loss. Photons are vastly more numerous than olfactory molecules, and carry incredibly small amounts of energy.

hasenj 15y ago

But light travels as a wave, and my humble (and possibly mistaken) understanding (or conjecture) is that photons are nothing but particle-like manifestations of whatever thing light is "really" made of. Waves travel in all directions, they get weaker over long distances, but it's not as though some photon particles reach us while others don't. (or is it?) I mean, if light is just photon particles, then we'd have to be really lucky to see that many starts that are billions of light years away. Of course, I could be totally wrong!

wtallis 15y ago
Light travels as both a wave and as particles. Whether you observe light to behave as mostly particle-like or mostly wave-like depends on the circumstances. When you are dealing with very small intensities, you usually observe mostly particle-like behavior (but wave-like behavior still shows up in things like self-interference as demonstrated by the two-slit experiment). If you think that it's unlikely for a photon from a distant star to reach us, then you are simply vastly underestimating the number of photons involved. Consider by analogy the process of smelling something: actual molecules need to fly off the object, travel through the air, and impact your nasal passages in order for you to smell it. That means that anything you smell is constantly dispersing its mass into the atmosphere, but an object can remain pungent for a long time without significant weight loss. Photons are vastly more numerous than olfactory molecules, and carry incredibly small amounts of energy.