October 16, 2019 0

How Close Are We to Photographing a Black Hole?


When we look up we see moons, planets, asteroids,
pulsars, star clusters, nebulae, stars as big as whole solar systems, and millions of
galaxies — you know what we don’t see? Black holes. Because no one has ever seen a black hole. Black holes are deep, dark, swirling sinkholes
of collapsed matter. That gravitational whirlwind that consumes
everything and crushes it. That place where not even light can escape… Except…THIS isn’t a black hole. This is an artist’s idea of what a black
hole might look like, or more precisely, the light around it – called the Event Horizon. Think about t.v. shows and movies like stargate
SG-1, Lost In Space, Star Trek..The Black Hole, and most famously Interstellar. They all have images of black holes, but no
one has ever actually photographed one. So, how close are we to taking a picture of
a black hole? Taking a picture of a black hole is expensive,
difficult, and takes a lot of smart people’s time. You’ve probably never even thought about
what a black hole looks like, because you thought “this is what a black hole looks
like!” But it’s not. So, why are scientists so desperate to see
one? Why does it matter? First. Science. Second. Black holes are incredible, and right now,
artists and filmmakers build conceptions based on what scientists tell them is important,
but we don’t know if these are right… these pictures are based on math…not in
reality. We’ve known about Black holes since the
early days of Einstein’s theories, but until we actually see one, there’s a part of us
that doesn’t want to believe that they’re real. This actually all started with that famous
equation: E=mc2. But math can only get us so far…I mean,
we knew Pluto was out there since the early 1900’s, and our best guesses told us it
was a boring icy ball. Until we flew by it in 2016, and actually
saw it. Imagine how we’ll feel when we see a black
hole with our jelly-filled light buckets. And this is what scientists are going to use
to snap a photo of a black hole. The event horizon telescope. It’s not just one telescope, it’s a network
of many all over the planet. This effectively creates a single telescope
as big as the Earth. The bigger the telescope, the more detail
they can see, and the further away. Which we definitely need to take the image
of a something like this black hole…Meet Sagittarius-A Star. Sag A-Star is at the center of our galaxy. It’s thousands of light-years away. There’s a second object that we’re also very
interested in and that is the black hole in the center of the galaxy, M87, also known
as Virgo A… M87 is an elliptical galaxy that’s located
about 17 megaparsecs away, so about 15 million light-years away. That’d be like trying to photograph an orange
on the surface of the moon from the earth or trying to pick out individual molecules
in a piece of paper in front of you. And they do this with a whole array of radio
telescopes spread around the world… not the kind you look through. They use radio wavelengths instead of visible
wavelengths… It’s a process called interferometry. Interferometry is a general technique to take
the signals from two separate receiving systems, in this case telescopes and interfering the
signals with each other. The word interferometry is the combination
of interfere — and meter or to measure. They’re measuring a pattern of interference
of the radio waves entering the telescope. By analyzing the interference pattern, the
data from the telescopes can be merged together, and images can be filtered from all the noise. These astronomers are using Very Long Baseline
Interferometry (VBLI), meaning the radio telescopes are far apart but are working together, .Which
brings us to April of 2017, when these astronomers pointed their telescopic array at the black
holes in Sagittarius-A Star and in M8716 for 5 nights. So, doesn’t that mean we took the picture? no. We didn’t. We took the data.We’re now starting to process
the data into a picture. Part of the difficulty of reconstructing an
image is that we don’t have all the data that we need. The cosmic signals that we are interested
are very weak. most of what we are recording is from the
receiver and is noise the data that we interested in is roughly 1 millionth of all that data. It is definitely a lot of astronomy and it
is a lot of computer science as well… so We’re talking about hundred of terabytes
of data per station. add it all together and it’s Petabytes. A petabyte of data is 1,000 Terabytes. That’s a lot. That’s 3,900 of the largest iphones. It’s so much that they can’t even upload
it. It’s physical. On hard drives. All that data has to be shipped to processing
centers from telescopes around the world –including at the South Pole, which has extreme weather…
so, the scientists have to wait months to even receive that data. There are two sites working on the data. The Max Planck Institute for Radio Astronomy
in Bonn, Germany and here at the MIT’s Haystack Observatory outside Boston. Once the data is all in one place, the scientists
have to correlate it. It’s like watching a 3D movie but where
each eye is seeing something different. The scientists need to match them up with
timing that’s more precise than atomic clocks on the GPS satellites. One of the possibilities is that this year’s
data won’t be sufficient to provide a good image, but with the addition of next year,
we will. Again, again we won’t know until we actually
are at that point in the analysis. With any luck, we’ll see the first image
of a black hole in 2018. If we can gather enough data, correlate it,
and analyze it to find the image of something thousands or millions of light years away. If. Then what will we see? The accretion flow will probably look more
or less like a crescent. That’s because we’re not viewing the accretion
flow face-on. We’re not quite viewing it edge-on but closer
to edge-on. So, We really don’t know what we will see,
was einstein correct? we won’t know until we see the image. If we produce a really nice picture, people
will say, “Wow, so that’s what a black hole looks like. That’s cool.” So we are pretty close to seeing our first
photographs of a black hole. If not in 2018, then maybe 2019. What do you think Astronomers will learn? What Will it look like? Do you think it’s gonna be different than
what we thought? Let us know and thanks for watching Seeker.

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