How do telescopes that are made up of several somethings miles apart work?

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I’ve seen talk of using the moon or even telescopes all over the world collectively work as a single telescope.

In: Planetary Science

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Anonymous 0 Comments

Light is a wave. Waves don’t just move in neat straight lines, and because of this you can’t take a wave and focus it down to a single point. The best you can manage is a hazy blob. This isn’t the fault of bad lenses – this is a fundamental limitation caused by waves.

What a lens does, really, is allow us to compare the wave in different places. It takes the wave from all across it and sends the wave to the same spot where it can be measured. The farther apart the waves can be collected, the better our data can be. A bigger lens, or a smaller wave, can both shrink our blob. Making a lens miles across is difficult, though. Since we really just need two measurements, one from each end of the lens, and not the whole lens, we can cheat a bit. We *can* just use “two parts of the same lens” that are really far apart, and not worry about any of the lens between them. Two “separate” telescopes that act like two parts of one lens. To do this you need to somehow take the waves from both, and transport that information to the same place to compare and measure it. This is the hard part. With radio telescopes it isn’t too bad, we can cram the signal into a wire and run the wire between the two. With visual telescopes the frequency is too high to do that, so we have to get really creative with transporting the light long distances but not destroying the information it contains.

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