The most detailed portrait yet of a black hole

Black holes: devourers of stars reveal their secrets


Paris: On Wednesday, three scientists were awarded the Nobel Prize in Physics for their research on black holes. Black holes are some of the most mysterious objects in the universe, they swallow stars, such as dust spots.

Such a powerful force caused them to change the laws of nature, and even Albert Einstein, the father of general relativity, did not believe that they could exist.

-Two varieties-

A black hole is a celestial body that compresses a huge object into a small space. Their gravitation is so strong that even without light, they can’t escape their flower gum.

This makes these exotic entities difficult to find. But scientists now know a lot about the impact of black holes on the surrounding environment.

There are two kinds.

The first is various garden black holes formed when the center of a large star collapses on itself to form a supernova.

Their mass may be 20 times that of the sun, but the space is very small.

Trying to see the one closest to the earth is like looking for a human cell on the surface of the moon.

In contrast, so-called supermassive black holes — such as the one sitting at the centre of the Milky Way for which two of Tuesday’s laureates were awarded prizes — are at least a million times bigger than the Sun.

Last month, teams of scientists from the US and Europe detected for the first time a so-called “intermediate mass” black hole with 142 times the mass of the Sun. It was formed, they determined, from the merger of two smaller black holes.

-Time stopper-

When Einstein’s General Theory of Relativity was published in November 1915, it overturned all previous concepts of time and space.

It describes how everything from the smallest atom to the largest supernova is kept under the control of gravity.

Since gravity is proportional to mass, an extremely heavy entity has a strong gravitational force, which may bend space and slow down time.

According to Einstein’s theory, extremely heavy masses (such as black holes) may stop time altogether.

However, Einstein himself did not believe in the existence of black holes.

British physicist Roger Penrose-who won the Nobel Prize on Tuesday-showed that general relativity could lead to these huge, all-swallowing objects.

-Supermassive black hole-

Perhaps the most famous black hole is located in the center of our Milky Way. The mass of Sagittarius A* is four million times the mass of the sun, and it is the monster that causes the unique vortices of stars in the Milky Way.

However, because black holes can swallow light, they are invisible and have been invisible for decades.

In the early 1990s, physicists Reinhard Genzel and Andrea Ghez each led a research team that used the latest technology to stare at the heart of our galaxy.

However, even with the largest telescope in the world, their line of sight is still limited due to distortion caused by the Earth’s atmosphere.

The same effect that makes the stars flash in the night sky destroys the clarity of the captured images of the Milky Way.

Genzel and Ghez helped develop new technology, including more sensitive digital light sensors and better smart optics, improving image resolution more than one thousandfold.

They used their new methods to track 30 of the brightest stars near the centre of the Milky Way.

One star, S2, was found to complete its orbit of the galaxy in less than 16 years. Our own Sun, by contrast, takes more than 200 million years to complete its lap.

The speed at which the stars were moving allowed both teams to conclude that it was a supermassive black hole driving the galactic swirl. 

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