What Is A Black Hole?
What Is A Black Hole?
A black hole constitutes a region within space where gravity exerts a mighty force, preventing even light from escaping. This gravitational strength stems from the compression of matter into a tiny volume. Such a phenomenon arises during the final stages of a star's life.
Due to the absence of light emission, black holes remain imperceptible to human observation, rendering them invisible. Nevertheless, the utilisation of space telescopes equipped with specialized instruments aids in the detection of black holes. These unique tools enable scientists to discern distinctive behaviours exhibited by stars in close proximity to black holes, distinguishing them from other stars.
How Big Are Black Holes?
Black holes exhibit a range of sizes, spanning from the minuscule to the colossal. The tiniest black holes, theorized by scientists, could be as minute as a single atom, yet possess the mass equivalent to a massive mountain. Mass refers to the quantity of substance, or "matter," an object contains.
Another classification of black hole is known as the "stellar" variety, which can weigh up to 20 times more than the sun. It is possible that Earth's galaxy, the Milky Way, harbours numerous stellar-mass black holes within its expanse.
At the pinnacle of the size scale are the "supermassive" black holes. These astronomical entities accumulate masses surpassing that of a million suns combined. Scientific evidence supports the presence of a supermassive black hole at the heart of every significant galaxy. Within the Milky Way galaxy, the supermassive black hole named Sagittarius A holds a mass equivalent to around 4 million suns. Its dimensions are such that it could fit snugly within a vastly expansive sphere capable of containing several million Earths.
What Do Black Holes Sound Like?
Within the void of space, the notion is that your screams would go unnoticed, yet in the vicinity of a galaxy cluster, your cries could potentially find an audience.
Researchers have unveiled approximately 34 seconds of authentic sound originating from the black hole situated at the core of the Persus galaxy cluster, an astonishing 240 million light years distant from Earth. The auditory experience, to put it mildly, evokes an eerie sensation.
The resonant, reverberating tones bear resemblance to the melodic calls of whales or the deliberate playback of a vinyl record set to a lower revolutions-per-minute rate.
How Are Black Holes Formed?
Most black holes come from the leftover bits of really big stars that explode in a huge blast called a supernova. (Smaller stars become something called neutron stars, which aren't heavy enough to trap light.) If a star is very heavy (about three times heavier than our Sun), it can be shown that nothing can stop it from collapsing because of gravity. But as it collapses, something strange happens. As the star's outside gets close to an invisible line called the "event horizon," time on the star slows down compared to time for faraway watchers. When the outside touches the event horizon, time stops, and the star can't collapse anymore – it becomes a frozen collapsing thing.
Even bigger black holes can be made when stars crash into each other. Not long after NASA's Swift telescope started in December 2004, it saw really bright but quick flashes of light called gamma-ray bursts. NASA's Chandra and Hubble Space Telescope then looked at the light left behind, and scientists figured out that these big explosions can happen when a black hole crashes into a neutron star, making an even bigger black hole.
