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tionis
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If we were to take a microwave picture of a region of space said to have a black hole, would we be able to spot the black hole? Would we see a cold spot surrounded by a more hotter background?
Nugatory said:A black hole in otherwise near-empty space so we won't see extraneous (and very obvious) phenomena like accretion disks of incandescent gas?.
Even for a supermassive black hole that is not accreting anything?Vanadium 50 said:If the cold spot were big enough to see, you're probably too close.
Wow! I thought supermassive black holes tidal gravity was less destructive because of the size of the BH.Vanadium 50 said:If a SMBH had the angular size of the moon, you'd be about a billion miles away. The gravity would be about 20g's, and in a few hours your day is going to get very bad.
tionis said:I thought supermassive black holes tidal gravity was less destructive
Ah, Ok, I got it now. So, Peter, If the sat were to hover at that distance where the BH would look like the moon like Vanadium said, would it be able to capture a noticeable cool, round spot in the microwave background?PeterDonis said:He's not talking about tidal gravity. He's talking about the proper acceleration you would need to maintain in order to "hover" at that altitude above the supermassive BH. You have to hover because at that distance there are no possible free-fall orbits around the hole.
tionis said:If the sat were to hover at that distance where the BH would look like the moon like Vanadium said, would it be able to capture a noticeable cool, round spot in the microwave background?
It just occurred to me that micowaves near the black hole would shift to the blue end of the spectrum, no? Wouldn't that make the BH hotter than the background?PeterDonis said:If it were looking directly towards the hole, yes, I believe so.
tionis said:micowaves near the black hole would shift to the blue end of the spectrum, no?
Black holes can be detected in the microwave background through a process called gravitational lensing. This occurs when the gravitational pull of a black hole bends and distorts the light passing by it, causing a characteristic pattern in the microwave background.
Spotting black holes in the microwave background can provide valuable information about the early universe and the formation of galaxies. It can also help us understand the distribution of matter and energy in the universe.
Scientists use specialized instruments, such as telescopes and satellites, to analyze the polarization and temperature fluctuations in the microwave background. This allows them to distinguish between the unique signature of a black hole and other objects in the background.
Yes, black holes can be detected in the microwave background from any location in the universe. However, the level of detail and accuracy may vary depending on the capabilities of the instruments being used.
Studying black holes in the microwave background can help us understand the evolution of the universe, the nature of dark matter and dark energy, and the role of gravity in shaping the structure of the universe. It can also provide insights into the origins of the universe and its ultimate fate.