On Wednesday, April 10-2019, astronomers revealed the first ever actual image of black hole. This is a historic moment for all of us. Black holes have captivated the imaginations of scientists and the public for decades.
Dr. France Cordvoa director of the National Science Foundation said
We have been studying black holes for so long, that sometimes it is easy to forget that none of us have actually seen one
Black holes are the most mysterious objects in the universe, they are cloaked by an event horizon that prevents even light from escaping, and yet the matter that falls onto the event horizon is superheated so before it passes through, it shines very brightly.
To get the real image of such a thing seems almost an impossible thing to do, but with lot of dedication and hard work we are now witnessing the history. To do this people have worked over a decade to link telescopes around the globe to make the earth sized virtual dish. The EHT (Event Horizon Telescope) achieves the highest angular resolution possible from the surface of the Earth.Telescope allows us to see what has traveled to us so far.
In April of 2017, all the dishes in EHT swiveled, turned, and stared at the galaxy which is 55 million light-years away from our planet, it is called Messier 87 or M 87. It has a mass 6.5 billion times that of the Sun and there is a supermassive black hole at it’s core and that is the one we all are seeing right now.
M87 shadow is very very small as compared to the galaxy that surrounds it. So in order to see the black hole, EHT team build a telescope as large as the earth itself, giving the wavelength of light that the EHT team was trying to observe.
To do this, EHT team use a technique called very long baseline interferometry. Radio waves from the black hole hit radio telescopes, where they are recorded with the precision of atomic clocks, that’ll lose only one second every 10 million years. By registering these radio waves so precisely it become possible to store them on hard disk drives, and then combine it precisely.
It’s exactly the same way that a mirror uses optical telescope to reflect light perfectly and synchronicity to a single focus and by doing this it become possible to synthesize a telescope that has resolving power turning the Earth into a virtual telescope.
All of this led us to the image that we all are seeing right now, once which was thought unseeable.