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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