BLACK
HOLES – SCI & TECH
News: Black hole is observed snacking on
sun-like star, bite by bite
What's
in the news?
●
Black holes, celestial objects known for their gluttony, usually eat stars
unlucky enough to stray too close to them in one big gulp, annihilating them
with their enormous gravitational pull. But some, it turns out, tend to snack
rather than gorge.
Key
takeaways:
●
Researchers said they have observed a supermassive black hole at the center of a
relatively nearby galaxy as it takes bites out of a star similar in size
and composition to our sun, consuming material equal to about three times
Earth's mass each time the star makes a close pass on its elongated oval-shaped
orbit.
●
Black holes are extraordinarily dense objects with gravity so strong that not even
light can escape.
●
The star is located about 520 million
light years from our solar system. A light year is the distance light travels
in a year, 5.9 trillion miles (9.5 trillion km). It was observed being
plundered by a supermassive black hole at the heart of a spiral-shaped galaxy.
Black
holes:
●
Black holes are regions of space-time where gravity is so strong that nothing, not
even light, can escape from them.
Types
of Black holes:
1.
Stellar Black Hole:
●
It is formed by the collapse of a single
massive star.
2.
Intermediate Black Hole:
●
Their masses are between 100 and 100,000
times that of the sun.
3.
Supermassive Black Hole:
●
Their masses ranging from millions to
billions of times that of the sun, found at the centres of most galaxies
including our own Milky Way galaxy.
Formation:
●
Most black holes form from the remnants of a large star that dies in a
supernova explosion. (Smaller stars become dense neutron stars, which are
not massive enough to trap light.)
Event
Horizon:
●
A black hole's “surface,” called its event
horizon, defines the boundary where the
velocity needed to escape exceeds the speed of light, which is the speed
limit of the cosmos.
Super
Hot X rays:
●
Some black holes steal material from their
companion star. As the material falls onto the black hole, it gets super hot
and lights up in X-rays.
●
The first confirmed black hole astronomers
discovered, called Cygnus X-1, was
found this way.
Tidal
disruption event:
●
Instead of just siphoning material from
the star like a smaller black hole would do, a supermassive black hole will
completely tear the star apart into a stream of gas.