Page 26 - Life beyond the Karman

NEUTRON STARS
Neutron stars are the remains of the cores of massive stars that have reached the end of their lives. When a medium-sized star collapses and explodes as a supernova, an incredibly dense core remains. This core is known as a neutron star and gets its name from the subatomic particles called neutrons, which are typically found inside the nuclei of atoms.
Neutron stars are the smallest and densest known class of stellar objects, except for black holes. These remnants are composed almost entirely of neutrons due to extreme pressure, causing electrons and protons to combine and produce neutrons.
Black holes
A black hole is a region of space-time where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape its event horizon.
The theory of general relativity predicts that a sufficiently compact mass can deform space-time to form a black hole. The boundary of no escape is called the event horizon.
A black hole cannot be seen because strong gravity pulls all the light into the middle of it, meaning material orbiting. It can get very hot and bright as it falls in.
Types of black holes
The two main types of black holes are stellar black holes and supermassive black holes
Stellar black holes form when enormous stars explode as supernovas at the end of their lives.
Supermassive black holes are bigger and are found at the centres of galaxies, often surrounded by a whirlpool of intensively hot glowing matter.
The temperature is of the order of billionths of a kelvin for stellar black holes, making them impossible to observe directly.
Space telescopes with special tools and features can help find black holes.
How Big Are Black Holes?
Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain.
The mass of stellar black holes can be up to 20 times more than the mass of the sun, while supermassive black holes have masses of more than one million suns put together. Scientists have found proof that every large galaxy contains a supermassive black hole at its centre.
The supermassive black hole at the centre of the Milky Way galaxy is called Sagittarius A.
Scientists use satellites and telescopes in space to see the high- energy light.
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LIFE BEYOND THE KÁRMÁN LINE - OUTER SPACE