BLACK HOLES – The great void

WHAT ARE BLACK HOLES ?

BLACK HOLES are points in space that are so dense they create deep gravity sinks. Beyond a certain region, not even light can escape the powerful tug of a black hole’s gravity. Because no light can get out, people can’t see black holes. They are invisible. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars.

HOW ARE THEY FORMED ?

The most well-understood black holes are created when a massive star reaches the end of its life and implodes, collapsing in on itself.In their final stages, enormous stars go out with a bang in massive explosions known as supernovae. Such a burst flings star matter out into space but leaves behind the stellar core. when there are no longer forces to oppose that gravity, so the star core begins to collapse in on itself.

If its mass collapses into an infinitely small point, a black hole is born. Packing all of that bulk—many times the mass of our own sun—into such a tiny point gives black holes their powerful gravitational pull.

BLACK HOLES SWIRLING WITH STARS

Researchers have long estimated that the Milky Way is home to hundreds of millions of black holes, extremely dense objects whose gravitational fields are so intense, not even light can escape. But finding these dark objects has proven extremely difficult and majority of black holes in our galaxy are invisible, so the only way to find them is by observing their gravitational effects on surrounding objects.

After decades of black holes being known only as theoretical objects, the first physical black hole ever discovered was spotted in 1971. Then, in 2019 the Event Horizon Telescope (EHT) collaboration released the first image ever recorded of a black hole.

Using the Event Horizon Telescope, scientists obtained an image of the black hole at the center of galaxy M87

TYPES OF BLACK HOLES

The most common types of black holes are the stellar-mass and supermassive black holes. Stellar-mass black holes are created when massive stars explode, leaving behind a black hole with the mass of just a few suns. Supermassive black holes exist in the hearts of galaxies and usually contain the mass equivalent of millions of suns.

SUPERMASSIVE BLACK HOLES- BIRTH TO GIANTS

Small black holes populate the universe, but their cousins, supermassive black holes, dominate. These enormous black holes are millions or even billions of times as massive as the sun, but are about the same size in diameter. Such black holes are thought to lie at the center of pretty much every galaxy, including the Milky Way.Almost every galaxy, including our Milky Way, has a supermassive black hole at its heart, with masses of millions to billions of times the mass of the Sun. 

The supermassive black hole that lurks at the center of our galaxy, called Sgr A*, has a mass of about 4 million times that of our Sun. A black hole is a place in space where gravity is so strong that neither particles or light can escape from it. Surrounding Sgr A* is a dense cluster of stars. It is 26,000 light-years from the Solar System

On January 5, 2015, NASA reported observing an X-ray flare 400 times brighter than usual, a record-breaker, from Sagittarius A*. The unusual event may have been caused by the breaking apart of an asteroid falling into the black hole or by the entanglement of magnetic field lines within gas flowing into Sagittarius A*.

Sagittarius A* is the black hole at the center of the Milky Way galaxy. Credits: X-ray: NASA

FAMOUS BLACK HOLES

Cygnus X-1: a stellar-mass black hole and x-ray source that lies some 6,500 light-years away. It is a binary system that contains a blue supergiant variable star and the x-ray source thought to be the black hole.

Sagittarius A*: the supermassive black hole at the heart of the Milky Way Galaxy. It lies in the direction of the constellation Sagittarius. This black hole contains the mass of about 4 million suns.

M87: this elliptical galaxy has a 3.5 billion solar-mass black hole at its heart. The black hole is surrounded by a disk of super heated material and has a jet of super heated material streaming away from the black hole that extends across 5,000 light-years from the galaxy’s core.

Centaurus A: this galaxy, which lies in the direction of the constellation Centaurus, is a giant spiral galaxy with an incredibly active nucleus. It contains a 55 million solar-mass black hole at its heart, with two jets of material that stream away from the galaxy at about half the speed of light across a million light-years of space.

Amazing Facts :

1. Black holes will spaghettify you and everything else.

Black holes have this incredible ability to literally stretch you into a long spaghetti-like strand. Appropriately, this phenomenon is called ‘spaghettification’

2.Einstein didn’t discover black holes.

Einstein didn’t discover the existence of black holes – though his theory of relativity does predict their formation. Instead, Karl Schwarzschild was the first to use Einstein’s revolutionary equations and show that black holes could indeed form.

3. Black holes are the ultimate energy factories.

Black holes can generate energy more efficiently than our Sun.

4.Black holes slow down time

To understand why, think back on the twin experiment that is often used to explain how time and space work together in Einstein’s theory of general relativity: One twin stays on Earth while the other one zooms out into space at the speed of light, turns around, and returns home. The twin that travelled through space is significantly younger because the faster you move, the slower time passes for you. As you reach the event horizon, you are moving at such high speeds due to the strong gravitational force from the black hole, that time will slow down

5.Anything can become a black hole, in theory.

The only difference between a black hole and our Sun is that the centre of a black hole is made of extremely dense material, which gives the black hole a strong gravitational field. It’s that gravitational field that can trap everything, including light, which is why we can’t see black holes. You could theoretically turn anything into a black hole.

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