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Light Echoes Solve Mystery of Tycho's Supernova
Ponca City, We love you writes "Powerful telescopes in Hawaii and Spain are using 'light echoes' from the original supernova explosion that have bounced off dust in the surrounding interstellar clouds to identify the precise type of supernova that Tycho Brahe saw 436 years ago. Although the echoed light from Tycho's supernova is around 20 billion times fainter than the original light observed in 1572, the team took identical images of the sky a few months apart and then digitally subtracted one from the other to find evidence for several sets of light echoes rippling across patches of dust in the northern Milky Way. 'Using light echoes in supernova remnants is time-travelling in a way, in that it allows us to go back hundreds of years to observe the first light from a supernova event. We got to relive a significant historical moment and see it as the famed astronomer Tycho Brahe did hundreds of years ago,' said Tomonori Usuda, of the Subaru Telescope in Hawaii. Tycho's original observations were particularly important as he immediately concluded that the new star, visible even by day, could not be closer than the Moon challenging the Aristotelian view of the cosmos, widely accepted since ancient times, which held that the sky beyond the Moon never changed."
This could be used to determine distances very precisely. If we know when that light was emitted and we know the speed of light, then we can calculate with great precision the distance from the star to the reflecting dust cloud.
"Echoes" evokes the idea that the light from the star first reaches us directly, then a delayed reflection of that light reaches us afterwards. "Reflections" are colloquially assumed to be instantaneous. I think it's a neat bit of semantics, really.
No kidding!!! What do you say at this point?
xxx times less than yyy == yyy/xxx.
It's common language these days, learn it!
A telescope array acting as an interferometer doesn't need to be a single large sensor like that. We can orbit the array with separations of 1E13, just beyond Neptune. That would give us resolution of something like 5.8E-20 arcseconds. The radius of that regular polygon with 10cm sides is about 7E21m, or about 740,000 light years. Which would show light that left Earth about 1.48 million years ago. Orbital arrays much closer to Earth are sufficient for looking for apples only 175ly away.
The signal to noise is of course extremely high ("astronomical"). That's why I mentioned the combined computing power of all the world's computers. We're gonna need a bigger boat, but that's a good sea to sail her on, to catch this shark :).
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make install -not war