Astronomers on April 10 unveiled the first
photo of a black hole which matched somehow with the pictures drawn by the
artists in last many years.
The image has a dark core encircled by a flame-orange halo of
white-hot gas and plasma.
Scientists have been puzzling over invisible
“dark stars” since the 18th century, but never has one been spied by a
telescope, much less photographed.
The supermassive black hole now immortalised
by a far-flung network of radio telescopes is 50 million lightyears away in a
galaxy known as M87.
How was it made possible?
Since April 2017, a global web of eight radio
telescope began surveying the Messier 87 black hole and the black hole in the
center of our galazy Milky Way.
In the centre of our galaxy the black hole is
known as Saggitarius A*. It has mass 4.1 million of our sun.
Mission Shakti and Controversy |
The black hole at the center of M87, by contrast, has a
mass equivalent to perhaps 7 billion suns, or 1,700 times bigger than our own
black hole. But at 2,700 times the distance, it was even harder to make an
image of.
These eight radio telescope are located in
six places- Chile, Mexico, Spain, Hawaii, Arizona and Antarctic and
collectively it is known as the Event Horizon Telescope (EHT).
One thing that made the work possible was not just the
number of telescopes collaborating in the search, but their geographic
distribution. The distance among the detectors—especially the 9,000-mi.
north-south stretch from Spain to Antarctica—effectively means a collection dish
nearly as big as the Earth itself. That allows for an enormous amount of data
to be gathered and collated
What are black holes?
A black hole (the phrase is usually credited
to the American physicist john wheeler in
1967, and is certainly a distinct improvement on the original label of
“gravitationally completely collapsed objects”) is a region of space in which
the gravitational field is so powerful that nothing, including electromagnetic
radiation such as visible light, can't escape its pull – a kind of
bottomless pit in space-time.
As its centre lies an infinitely small infinitely dense singularity a
space where the normal laws of physics break down.
How does the Black
hole take birth?
When a star dies, it collapses inward
rapidly. As it collapses, the star explodes into a supernova—a catastrophic
expulsion of its outer material. The dying star continues to collapse until it becomes a singularity—something
consisting of zero volume and infinite density. It is this seemingly impossible
contradiction that causes a black hole to form.
The extreme density of the new singularity pulls everything toward
it, including space-time.
What is singularity?
A singularity means a point where some
property is infinite. For example, at the center of a black hole, according to
classical theory, the density is infinite (because a finite mass is compressed
to a zero volume). Hence it is a singularity. Similarly, if you extrapolate the
properties of the universe to the instant of the Big Bang, you will find that
both the density and the temperature go to infinity, and so that also is a
singularity. It must be stated that these come due to the breaking down of the
classical theory.
True to the nature of the science, the picture does not
show the black hole itself. The defining feature of all black holes is that
they are so dense, generating a gravity field so powerful, that nothing, not
even electromagnetic energy—which, of course, includes visible light—can escape
their pull. What the pictures reveal instead is the black holes’ so-called
event horizons, the swirl of gas and dust and stars and light itself, circling
the black hole drain, before they’re sucked inside never, ever to re-emerge.
No comments:
Post a Comment