Big Black Hole – How big is the picture?

It is making the news in various places that we have the first picture of a black hole… sort of. The part I find interesting is the size of the hole and of the picture, yeah, the size of the picture is impressive. More so than it looks

First Image showing Einstein predicted black hole. 4/2019

The black hole is in the constellation Virgo. The app Skyview (Android and iOS) or StarDate.org will help you find Virgo in the night sky. But you can’t see the black hole with your eyes. At 55 million lightyears away the hole which is 6.5 billion times heavier than our sun (10 billion kilometers in diameter – the diameter of Neptune’s orbit is 9 billion km) is too small to see.

To photograph it 8 radio telescopes located in Hawaii, Spain’s Sierra Nevada, the Chilean desert, and on the Antarctic ice sheet were used to create a huge virtual telescope. Each scope took images totaling about a petabyte of data (or 1 million megabytes). At that size, it was faster to fly the stacks of disks via FedEx to Massachusetts and Germany for processing by a supercomputer called a correlator rather than try to ‘upload’ the information. According to MeridianOutpost.com a petabyte of data would take 15,770 hours on an OC3 (155Mbps) connection (over 2 years).

The data from the telescopes have to have noise and artifacts of each telescope removed. Haystack Observatory in Massachusetts and Max Planck Institute in Germany did the correlation and cleanup, a long tedious complex process. The resultant clean data was sent to four teams to assemble into the image… images.

All that and all we got was a picture of the black hole’s shadow… Well, you can’t really see a black hole as it sucks in everything around it including light. The ‘shadow’ is what Einstein predicted. Chalk up another one for old fuzzy top.

Actually, the tech to capture the image is far more impressive than the final image looks. The idea for how to capture the image was formed in 2000 and between then and now the tech was developed. Ways to synchronize the telescopes with high precision atomic clocks (9 billion tics per second) were worked out. Precise time at the needed level of accuracy is way complicated because of relativity. Moving a clock in a 600 mph or 965kph airplane changes the clock time. Re-syncing by radio signal between locations is complicated by signal travel time which changes with the weather. Time accurate to the 10,000,000th or 100,000,000th of a second and beyond is a major PITA. Weather at all locations had to be clear… developing patience? Ways to collect huge streams of digital data at high speed had to be devised. Telescope pointing to precisely focus on the same point from all the telescopes had to devised and tested. Figure that out when the surface of the planet you are on is moving at 1,024 mph at the equator and almost zero at the poles while the whole planer flies around the sun at 67,000 mph or 107,000 kph in an elliptical orbit and the planet wobbles. Then they had to figure out how to put it all together and take the picture.

Impressive.

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