It's been a great week for black holes. A study this week noted ancient vigorously growing black holes at their centers of galaxies. Another found powerful gamma-ray flashes from a gigantic black hole that consumed a star.
A good time, we thought that, for some basics on black holes. A black hole is an object that has collapsed under its own weight to a point, creating an object that is extraordinarily small, still enormously thick. Sucks in anything that can absorb and once formed, nothing, not even light, can escape its gravitational attraction.
"Are the most voracious eaters of the universe," said Kevin Schawinski, a Yale University astrophysicist. "You can only go in, and you can never go back."
There are two main types of black holes. There are black holes, born after the death of stars, which are more or less a couple of times the mass of our Sun. These stars end their lives, when the hydrogen fuel which composes the star burns out, causing the star to collapse.
Then, there are black holes, ranging from a few hundred thousand times the mass of our Sun for a few billion times the mass that exists at the center of galaxies. Black hole found in the center of the milky way is 4 million times the mass of our Sun.
There are two schools of thought about how these black holes. It is possible that they are caused by the death of the universe's first stars, which were massively larger.
Another recent theory predicts gas swirling disks and funnel as a tornado. The universe was filled with gas and radiation. In some places, gravity caused the gas to fall into halos of dark matter and gas in the form of discs, Priya Natarajan, a theoretical astrophysicist explained. Instability in these discs caused the swirling effect, where gas begins to funnel from outside.
The channeling can be compared to the formation of tornadoes. "The flow is like a vortex tornado," said Natarajan. "Very fast, dramatic and violent. And it can happen quickly. "
Scientists this week announced the discovery of a population of hyperactive child, black holes and their host galaxies grew up with. They represent the oldest ever found black holes and maybe are caused by this phenomenon of convey said Natarajan, also one of the authors of the study. Black holes date back to 800 million years after the Big Bang-that is 12.7 billion years ago.
This is an extremely young in cosmic time. To put it in perspective, our universe is 13.7 billion years now-these black holes existed in its infancy.
Black holes are supermassive variety, even though they have not yet reached the full mass. And the data indicate that are closely linked to the formation of galaxies.
"We believe that the growth of black holes and the growth of galaxies simbioticamente are linked," said Schawinski, also an author of the study. "We are pushing all the way to the very, very beginning of the universe and ask questions about how it works and how this relationship has begun."
The finding, published this week in the journal, Nature, is based on computer models, using data from NASA's Chandra x-ray Observatory. Scientists pointed Chandra patch of sky where the Hubble Space Telescope has spotted galaxies and observed for 45 days.
They tried for x-ray emissions as markers to detect active or feeding black holes. As matter falls into dark holes, which emits energetic x-rays. Schawinski calls them "the scream of death."
It turns out that over 30 per cent of black holes in distant galaxies contained, but it took years to find them, because they were wrapped in cosmic dust. "It took seven years to detect signatures of black holes, first in growth," said Ezequiel Treister, lead author of the study.
This is the first time that we are singling out when these black holes were forming and growing, and "we're also getting the first clues to how these black holes grew," said Mitchell Begelman at the University of Colorado, Boulder, which was not involved in the study, but attended a June 15, NASA presser on the topic.
Still in question, though, is how to shape these black holes. It was from massive gas collapsing under their own gravity straight down into a black hole, or was the death of the first generation of stars, believed to be much more massive than a typical star?
Hope, scientists say, is to use Hubble and Chandra to push even further back into the past to answer these questions and understand how these things.
This finding is not going to make better the lives of anyone, but it is important to human curiosity and discovery, Natarajan said. Cosmologists, said, I'm an armchair explorers of our generation. And it's fun work, he added.
"I can't imagine doing anything else," he said. "I really can't imagine doing something else."
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