Stories tagged astrophysics
Black hole in action: Artist's rendition of a distant super-massive black hole warping space while busy eating up stellar material.
Courtesy NASA/JPL-CaltechScientists now have a better idea why stars can still form out of giant molecular clouds being ripped apart by the gravitational pull of a nearby massive black hole.
The observed existence of huge stars in eccentric orbits around the super-massive black hole believed to be located at the center of our Milky Way galaxy has puzzled scientists. How can stars form in such extreme environments? Gravitational forces would be tremendous near the black hole, tearing apart everything in the immediate region.
The computer simulations, done by researchers from St Andrews University in the UK, show how a molecular cloud – a normal stellar nursery – is torn apart by the black hole’s immense gravitation pull. Although the powerful gravity-well eats a huge portion of the gas cloud, the remaining gases are still able to accrete more material and coalesce into stars.
This is possible because as a molecular cloud enters the black hole’s gravitational field it begins to form into a spiraling elliptical disk. The disk’s matter nearest the black hole is sucked into the gravitational vortex, while energy is transferred to the remaining outer material. This transferred energy allows the remnants to retain the eccentric orbital path as they form into huge stars many times the mass of the Sun.
"These simulations show that young stars can form in the neighborhood of super-massive black holes as long as there is a reasonable supply of massive clouds of gas from further out in the galaxy," said co-author Ian Bonnell. The study’s results appear in the current issue of Science.
The stars live fairly short lives - perhaps only about 10 million years. But their existence could help explain some of the mysteries surrounding black holes in galaxies.
LINKS
Story on BBC website
Science magazine abstract
More on super-massive black holes
Tags : Ever wonder how gold is made. One explanation of the origin of gold is from the collision of neutron stars.
NASA Science website is an awesome resource
NASA Science website
Courtesy NASA To show how useful this site can be, here are links to pages I found as I dug deeper into just one of the many areas on the NASA Science website.
Science for different levels of learning
The NASA Science website provides learning opportunities for four learning groups.
Earth, sun, planets, and astrophysics
The NASA Science website is divided into these parts.
A terrifying burst of cosmic energy: JGordon not pictured. (Image courtesy of Wikimedia Commons)Scientists have recently reported observing a massive, and as of yet unexplained, burst of radio energy from across the universe. At the time of the event, I was probably in the shower, or watching TV, and, in either case, too far from my radio telescope to see what was happening.
Researchers say that the burst was unlike anything seen before, coming from at least one and a half billion light years away, and giving off as much energy as a large power station running for two billion years. I guess I have to take the scientists' word for it, although that seems like an awful lot of energy for me to miss. The event lasted for only five milliseconds, though, so it seems possible that it could have slipped my notice.
"The burst may have been produced by an exotic event such as the collision of two neutron stars or be the last gasp of a black hole as it evaporates completely," says Professor Duncan Lorimer of the University of West Virginia. Based on my own knowledge of cosmic events, I'd say it's equally likely that the energy burst came from a galactic scale conflict between, say, Thanos and Adam Warlock, or the utter destruction of a planet, as observed in Star Wars IV: A New Hope. However, I can't yet say either way for sure.
Scientists believe it's possible, however peculiar it may seem, that similar events may be occurring several times a day. The difficulty in actually spotting one just comes from the sky being so big, a fact that I can confidently confirm.
The moon.: Image courtesy Mdf.
The Space Telescope Science Institute (the Hubble Space Telescope's science home), is conducting a three-day workshop beginning November 28 that will feature a roster of scientists, engineers, and astronauts presenting their thoughts about what NASA's return of human presence to the Moon could mean for astrophysics.
You can see the presentations live, or view previous webcasts from the presentations, by visiting the Space Telescope Science Institute’s webcast page.
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