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Snapping a black hole

By David, 16 April 2019 News

Scientists have just announced that they have the first photo of a black hole! But what does that actually mean? Read on to find out.

Glowing red and orange donut shape on a black background.

This is the first ever photo of a black hole!
Image: Event Horizon Telescope

I’ve seen pictures of black holes before, how is this one different?

While there have been many realistic artworks or ‘artists’ impressions’ of black holes, this is the first genuine image of a black hole. However, it’s a bit different from your everyday photo. The new picture shows radio waves rather than the visible light we normally see with our eyes.

What are we really looking at?

The image above shows the black hole in the middle of a galaxy called Messier 87.

Black holes are, as their name suggests, black. They have such strong gravity that not even light can escape. The black hole does not cover the whole dark area in the image – it’s about one third the width of the dark section inside the ring.

The orange ring in the image is a disc of matter spiralling into the black hole. The matter in the disc is extremely hot, maybe 100 billion degrees.

The brighter section of the ring is where matter is moving towards us and the darker section is where it’s moving away. Scientists can use this info to work out which way the disc is spinning – it’s going clockwise!

Bright white light in a black background.

Messier 87 is a galaxy in the Virgo constellation
Image: NASA/Space Telescope Science Institute/WikiSky

How did they get the image?

From previous research, scientists knew there was a massive black hole in Messier 87 that they could point their telescopes at.
Black holes are relatively small and tricky to see with telescopes. This black hole is one of the largest we know of and it’s roughly the same width as our solar system. That’s small compared to the size of a galaxy.

There isn’t a single telescope on Earth that could make out something so small, so far away. Instead, the team used eight radio telescopes across four continents. Over 10 nights, these telescopes looked towards the centre of Messier 87.

The telescopes collected five petabytes of data (that’s five million gigabytes) that needed to be combined. The team couldn’t send that amount of data across the internet. Instead hundreds of kilograms of hard drives were flown around the world.

With all the data together, the scientists were able to get the same resolution (fine detail) as one giant, Earth-sized telescope. The combination of telescopes, known as the Event Horizon Telescope array, was just good enough to reveal this black hole.

Check out some fantastic facts about the most famous black hole expert, Stephen Hawking

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