10 votes

Why are radio telescopes in orbit radio telescopes?

The biggest reason for wanting to put a radio telescope in orbit is to perform interferometry. For many single-dish telescopes, the best angular resolution achievable at a specific frequency depends ...
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8 votes

About the non-intuitive announcement at 12 May 2022 of the EHT team that spin axis of Sgr A* Black Hole facing Earth?

I think what you mean is that the spin axis of the black hole is not aligned with spin axis of the Milky Way? NB: That's about all you can say - the conclusion of the actual science paper (Akiyama et ...
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  • 110k
7 votes
Accepted

How can we extract the Doppler shift of supernovae?

TL; DR you measure the redshift of the host galaxy, not the supernova. Indeed, the intrinsic blue-shifts or complicated P-Cygni profiles of expanding supernova matter do not make for precise or ...
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2 votes

How can we extract the Doppler shift of supernovae?

Since a supernova tells the observer how bright the event is seen to be at its distance when it is always (approximately) the same standard actual brightness, this is the method used to calculate the ...
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  • 444
2 votes

Wouldn't our own EM emissions be good the places to look for signs of intelligent life?

Your question is based on the false assumption that we couldn't detect extraterrestrial radio waves just because we happen to emit radio waves at the same frequencies. Antennas are directional, and we ...
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  • 16.6k
2 votes

Wouldn't our own EM emissions be good the places to look for signs of intelligent life?

The majority of the EM emissions of human beings are in the infrared part of the spectrum. Those emissions are many, many orders of magnitude smaller than those of the Earth in the same IR band, and ...
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