I’m not sure if I worded my question correctly, but let me try to explain more.
If we use a giant telescope to look at another planet 10 light years away from us, we would be looking at how it was 10 years ago. The thing I don’t understand is how does light store and also transfer all the information about that planet (or all the “data” that ends up in our eyes) and yet it’s still the fastest thing.
In: 94
Coming off the question of this guy, how the fuck do photons carry color.
Like I get that it’s a different frequency and whatever, but this shit is confusing.
With what your describing, the light isn’t storing information. We “see” when light reflects off a surface and then enters our eyes. Obviously is we see a flower that light travels a very short distance to out eyes so we see things as they are right now.
Light is fast and travels at a certain speed. The distance it can travel in one year is called a lightyear. If something is 10 lightyear a way and we see it now, we’re seeing it at the moment it reflected off of that surface 10 years ago.
> how does light store and also transfer all the information
“Information” isn’t really a “thing” in the sense you seem to be imagining it. Instead information is conveyed through changes or differences in something, like a light changing frequency or intensity. That doesn’t really have anything to do with how quickly the light can travel.
Think about if I have a sheet of paper which can either be red or green. If the sheet is red it means “stop”, if it is green it means “go”. The paper can only have two states so it can only convey a small amount of information, but it doesn’t matter how large or small the piece of paper is. Even if I made the paper enormous, like 20 tons of paper, it doesn’t store and transfer any more information than if it was a fleck you could barely see. What would make the paper contain more information is if I divided it up into a bunch of sections each of which could be various colors to signify various things. The number of states the paper can be in vastly increases and it can contain more information despite being of similar size to the single-color piece of paper.
The same concepts apply to light. With data transfer on Earth through fiber-optics it usually comes down to how many frequencies of light you can monitor and how quickly the signal can be changed. In that sense the speed of light is a benefit because if I flip a light on and off a billion times a second it moves quickly enough to be able to distinguish the difference, as if it was slow like sound one signal wouldn’t have time to leave before the second signal was attempted to be transmitted.
In the case of light from distant stars or planets it is usually the combination of the entire spectrum of light that tells us a lot about the objects viewed. The number of different states that the spectrum of light can be in has nothing to do with how quickly it can travel.
It comes down to light is *small*. Photons are much (much much much) smaller than everyday items we interact with, so they can create *very* high resolution pictures. Imagine you’re trying to figure out the shape of an everyday object, and you’re doing that by throwing things at it and seeing how they bounce off.
If you throw bowling balls you’re really not going to learn much…maybe a rough outline, if you’re lucky. Ping-pong balls? Now you can see features down to about a few inches. It turns out the ability to resolve detail is basically the same size as the “ball” you’re throwing at the object. Photon make *extremely* tiny balls, so they can “see” a huge amount of detail. And they come in different colours, so not only do we get boundaries and brightness (vaguely equivalent to black and white) but we also get colour.
Light is also very fast, which makes it good for transmitting data fast (like in fiber optics), but that’s not really the same thing as looking at things in at high resolution.
How does it “store” the data? It doesn’t. The light is just in transit for 10 years.
How does it carry such a huge amount of data? There is a huge amount of light.
So a billion billion billion photons leave a sun and hit a planet and bounce off towards us.
The photons travel for 10 years.
10 years later, we collect the photons in a telescope. Each photon bounced off a different part of the planet, and so gives us a tiny bit of information about that part of the planet. Add together a billion billion billion tiny bits of information, and you get a lot of information.
When you look at something far away with a telescope, it works the same way as when you look at something nearby with your eyes. The only difference is that the light had farther to go, and the telescope has to be bigger to collect more of it.
So the light carries the same type of information your eyes get, which is just the color (wavelength) of the thing and the direction the light came from. The telescope focuses it back into an image of the thing.
I think I can do this! So when people wanted to communicate or send information over distances we developed what smoke signals? Which were short or long blooms of smoke viewed and translated over a distance. Then we got oh so smarter and figured we would write whole letters or communicate a verbal message through a message carrier. So more info but slower because we had to transport it ourselves. Then electricity and Morse code! So back to short long smoke plumes but they move at the speed of electricity/sound (ah cause they are beeps!). After that A. G. Bell (or really someone else he stole it I think) came up with a telephone. This and radio made it so we could actually speak with someone far away so even more information! So light travels faster than like anything right? What if we could sense if a piece of light, a photon, was a long plume of smoke or a short one? So a small bit of info like before but you get it at the speed of light! Now what if we could do this with 100 photons that’s like a sentence at the speed of light but what if we could do more like 1000 photons, a page, or a million like a book all at once then a movie then a hard drive then all the hard drives. If you have something like a light telephone you can gather and understand all that data and boom light transports a ton of data. Maybe this helps this is not my field lol.
Sorry not sure about storing data but I guess if you could get a piece of light to do it’s thing indefinitely and you could still read it with your light telephone it would always read the same effectively storing it? No sure…
It might help to understand that things moving at the speed of light do not experience time. This has the effect that light (effectively) does not change until it hits something. In the vacuum of interstellar space there is very little stuff for light to interact with. Therefore, by the time reaches us from distant places, it is almost exactly the way it was when it left that place.
If you have ever taken a long exposure picture, you are using the same principles that telescopes are using. There is very little light that reaches us from distant stars, so you have to collect light for a long time to get an image. Even then, you will only gather the light that reached the telescope. Astronomers use computers to process these long exposures to make the images that you see.
We use our understanding of physics to add more information than is immediately apparent. For instance, by finding the frequency bands of the light, we can tell which elements are emitting light. We can take pictures over time and figure out how fast and relative direction it is moving. We can take pictures at different wavelengths to get a more full understanding of its surroundings. We can use that information to determine how massive the object is.
The most ELI5 is probably to just imagine taking a picture of a candle from a mile away. Your camera is only going to capture what it is able to. You can get a better lens, enhance the image with software, take multiple pictures, and fill in the gaps with knowledge. You could probably tell how big the candle is, how big the flame is, and even how hot the candle burns. You still would not be able to capture every detail. But you can get pretty accurate.
It takes 8 minutes for the light from our star the sun to reach us. Your planet’s light, 10 light years from us, will just take a bit longer.
“Energy cannot be created or destroyed, it can only be changed from one form to another.”
― Albert Einstein
Well light does not store data in a way a cargo ship stores cargo. We encode information in the light itself. The same way as when as kids we send signals with a flashlight. 3 short blinks mean come over. The light is just light and carrys no information in that sense. But because it bli ks 3 Times we can extract information from it.
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