MessageToEagle.com - We know from important astronomical observations made in the past decade
that a massive black hole exists in center of the Milky Way.
Its position is equivalent to a well known andvery complex Sagittarius A (or Sgr A).
This makes Galactic center - with supernova explosions, stars crowding each other, tremendous gravitational forces
from a supermassive black hole - a unique space in the Milky way and the nearest massive black hole system.
Is this environment hospitable enough for a planet forming?
Simulation of gas cloud approaching the black hole at the centre of the Milky Way. Credits: ESO
Click on image to enlarge
In this artist's conception, a protoplanetary disk of gas and dust (red) is being shredded by the powerful
gravitational tides of our galaxy's central black hole. Credit: David A. Aguilar (CfA)
Surprisingly, a new research by astronomers at the Harvard-Smithsonian Center for Astrophysics shows that planets
still can form in this cosmic maelstrom. For proof, they point to the recent discovery of a cloud of hydrogen
and helium plunging toward the galactic center.
They argue that this cloud represents the shredded remains of a planet-forming disk orbiting an unseen star.
"This unfortunate star got tossed toward the central black hole. Now it's on the ride of its life, and while
it will survive the encounter, its protoplanetary disk won't be so lucky," said lead author Ruth Murray-Clay
of the CfA. The results are appearing in the journal Nature.
Murray-Clay and co-author Avi Loeb propose a different explanation. Newborn stars retain a surrounding disk
of gas and dust for millions of years. If one such star dived toward our galaxy's central black hole, radiation
and gravitational tides would rip apart its disk in a matter of years.
They also identify the likely source of the stray star - a ring of stars known to orbit the galactic center at a
distance of about one-tenth of a light-year. Astronomers have detected dozens of young, bright O-type stars in
this ring, which suggests that hundreds of fainter Sun-like stars also exist there.
Interactions between the stars could fling one inward along with its accompanying disk.
Although this protoplanetary disk is being destroyed, the stars that remain in the ring can hold onto their disks.
Therefore, they may form planets despite their hostile surroundings.
As the star continues its plunge over the next year, more and more of the disk's outer material will be torn away,
leaving only a dense core. The stripped gas will swirl down into the maw of the black hole. Friction will heat it
to high enough temperatures that it will glow in X-rays.
"It's fascinating to think about planets forming so close to a black hole," said Loeb. "If our civilization inhabited
such a planet, we could have tested Einstein's theory of gravity much better, and we could have harvested clean
energy from throwing our waste into the black hole."
Physicists Challenge Validity Of Big Bang Theory
We all know that the Big Bang theory is an effort to explain what happened at the very beginning of our universe.
However, Australian team of theoretical physicists at the University of Melbourne and RMIT University say that it's time to change our understanding of this process.