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Comment by jocaal | Hacker News Reader

Why do we need radio telescopes. Satellite communications are infinitely more useful for people on earth than some research papers about things light-years away

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> Why do we need radio telescopes.

Because they provide data that other types of telescopes do not. We have X-ray telescopes. We have infrared telescopes. We have optical telescopes. Also as a bonus, for ground based radio telescopes, we can use them 24/7 instead of waiting for nighttime.

Yes, but if it hadn't been for the efforts of visionary scientists at NASA trying to reach the stars, there would be no means of putting those satellites into orbit.

This is the but I don’t see the relevance. Is there an argument / position there or just an observation?

The point is basic science (e.g. radio astronomy) is, if not necessary, then highly desirable, because it can lead to unimaginable advancements in humanity (or in a country’s technological and military capabilities if that’s how you think).

Sure, and industry is also valuable and contributes to progress. I don’t think it’s useful to say one must always take priority over the other regardless of specifics.

I don’t think that’s useful either and nobody said that.

Ironically, those satellites would not be able to communicate effectively without the understanding of relativity that was obtained by looking at things light-years away.

Einstein developed relativity from mathematical reasoning. A major influence was the michaelson morley experiment, which was solely done on earth. Relativity was developed in the early 1900's and the first radio telescope was made in the 1930's. Also, orbital mechanics uses mostly Newtonian mechanics and the communication of satellites is radio waves which were understood way before einstein. There is no relativity involved. Literally everything you said is factually incorrect.

Satellites experience time dilation because of their orbital velocity and gravitational field being significantly different at their altitude. Without accounting for this, the clock drift would become unmanageable and Newtonian models are insufficient to correct for it.

You're right that the majority of Einstein's theories were ultimately thought experiments but getting the parameters correct involved a lot of measurements and experimenting, to get to where tech like GPS and StarLink can be accurate. We were also looking at far away stars for centuries before Einstein so that he could have the environment for his ideas to be discussed, which I was including in my phrasing "looking at things light-years away."

I wasn't saying it to start an argument, though. I wanted to counter the rather dismal view of "why do we need radio telescopes."

Einstein developed a theory that includes General relativity and special relativity. Experimental results confirms both of them, with special relativity being the easiest one to understand the consequences of. Without experimental confirmation, neither theory would be valuable.

Communication requires accurate timing. Time dilation occurs between Earth and satellites, a phenomenon that isn't part of Newton mechanics, so relativity is indeed involved.

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