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5 facts about black holes explained!


Image courtesy NASA/JPL-Caltech

Almost five years ago in early 2015, researchers from Peking University discovered one of the biggest black holes 12.8 billion light years away from Earth!

That means the light surrounding the black hole started its journey to Earth less than 1 billion years after the Big Bang.

Scientists have been looking into black holes since 1783, when scientist John Michell first proposed the idea that they were possible.

But after all this time they are still a mystery in many ways!

We may still be learning about these space marvels, but read on to find out what we do know about black holes.

1. Black holes used to be stars

A star implodes to create a black hole

The core of a star has collapsed, forming a black hole inside. Within a few seconds there is a gamma-ray burst of matter away from the balck hole. (Image courtesy NASA/SkyWorks Digital)

Want to know how a black hole is born?

Stars live a very long time, but just like us, they don’t live forever. They slowly burn through the fuel that keeps them shining.

When they run out, one of three things happens, mainly depending on its mass (which is how much matter something contains). The star will either transform into a white dwarf, a neutron star or a black hole.

If the star is big enough (like 10 or 15 times as big and heavy as the sun), it will explode when it reaches its end! The explosion causes the star to cave in on itself, making it much smaller. Because the size of the star gets smaller but the mass of it does not, the gravity surrounding the star becomes so strong it absorbs everything around it, including light. That's how a black hole is born.

2. There are 3 types of black holes

a supermassive black hole

An artist's concept depicts a supermassive black hole at the center of a galaxy. (Image courtesy NASA/JPL-Caltech)

Want to learn the different kinds of black holes? Here they are:

  • Primordial: These are considered to be tiny! They range from the size of a single atom to a mountain. Mountains probably don’t seem tiny to you, but space is a mighty big place!
  • Stellar: These are the ones found most often. They are about 20 times bigger than the Sun!
  • Supermassive: The black hole discovered in 2015 falls into this category. To be in this group, the hole has to be more than a million times heavier than the Sun!

What else could be hiding in space? Maybe aliens?! Check out 2 of Canada's famous unsolved UFO mysteries!

3. You can’t see them with the naked eye

A black hole swallows up a star

An artist's concept shows a supermassive black hole at the center of a far-away galaxy absorbing the last pieces of a star. (Image courtesy NASA/JPL-Caltech)

No matter how hard you stare, you won't be able to spot a black hole all on your own!

The reason black holes are so black is because they consume everything around them, including light! That's because the gravitational pull at their centre is super strong.

But with no reflection, we have nothing that can detect the hole directly. So instead, scientists look for the traditional effects a black hole has on its surroundings.

When a star is being pulled into the hole, it breaks apart and becomes distorted. As it’s sucked in, the bits of matter from the star move faster, create intense heat and throw off a glare of X-rays. That’s what astronomers can use to identify a hole.

4. Black holes helped create galaxies

A black hole at the center of a star-rick galaxy

An artist's concept shows a primitive supermassive black hole (central black dot) at the core of a young, star-filled galaxy. (Image courtesy NASA/JPL-Caltech)

Astronomers aren’t entirely sure yet what part the black holes played in the creation of galaxies. But one theory is that a large star exploded, a black hole formed and the rest of the galaxy was created around it!

5. There’s a black hole in the Milky Way

The Sagittarius A black hole in the center of the Milky Way

An artist's concept shows the activity at the core of our Milky Way galaxy where there is a supermassive black hole in the region known as Sagittarius A*, or Sgr A*, with a mass of about four million times that of our sun. (Image couresy ESA–C. Carreau)

Did you know our very own galaxy has a black hole in the centre known as Sagittarius A*?

In fact, it's believed by scientists that there’s a supermassive black hole in the middle of almost every galaxy!

Because the pull of a black hole is so strong, you might wonder whether Earth is in any danger of being sucked into one of the supermassive varieties.

Well, worry not! Sagittarius A*, the Milky Way’s black hole, is 26,000 light years from Earth. That's too far away for it to affect us! Phew!



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