- Black holes are formed from the remnants
of collapsed stars. A black hole consists of a large mass squashed so much
that not even light can escape from its force of gravity.
-
- For many years scientists have speculated
that at the centre of our galaxy there may be a great concentration of
matter in the form of a supermassive black hole. Now they have some evidence
for it.
-
- It has been found because of the black
holes gravitational effect on nearby stars and gas clouds.
-
-
- Using the Keck telescope atop the Mauna
Kea extinct volcano in Hawaii, astronomers have tracked the movements of
200 stars near the galactic centre.
-
- Some of them displayed signs of influence
by extreme gravitational forces.
-
- These stars are spiralling around the
black hole at speeds of up to three million miles per hour - about 10 times
the speed at which stars typically move.
-
- To account for these speeds it is estimated
that an object 2.6 million times more massive than the sun must be concentrated
into a single black hole.
-
- The centre of our galaxy lies 30,000
light years away behind vast clouds of stars, gas and dust.
-
- To peer through this obscuration the
scientists used a technique called infrared speckle interferometry. The
procedure involves taking thousands of high-speed, high-resolution snapshots.
-
- Using this technique in 1995, scientists
witnessed the disappearance of a star that was, at the time, the closest
object to the black hole.
-
- Whether the star was sucked into the
black hole, or simply went behind it, scientists may never know.
|
