Black Hole's and other Space Related Discussion

[NWOWolfpack]

Six months ago, satellite telescopes spotted an exceptionally bright burst of energy that would have been the most distant object in the universe ever visible to the naked eye, if anyone had noticed it.

Even though no humans have reported seeing it directly, the gamma-ray burst, an explosion that signals the violent death of a massive star, is changing theories of how these events look.

Gamma-ray bursts are typically accompanied by intense releases of other forms of radiation, from X-rays to visible light.

This burst, dubbed GRB 080319B, was first detected by the Swift satellite on March 19, while the spacecraft was serendipitously looking at another gamma-ray burst in the same area of the sky.

The light it emitted in the visible part of the spectrum was so intense that the burst would have been visible to the naked eye in the constellation Bootes for about 40 seconds.

No other gamma-ray burst has ever been visible without a telescope.

The incredible amount of energy given off across the entire electromagnetic spectrum during a gamma-ray burst is what Jonathan Grindlay of the Harvard-Smithsonian Center for Astrophysics calls "the birth pangs of a black hole. This is the scream."

It took the light of GRB 080319B about 7.4 billion years to reach Earth, placing the explosion "more than halfway back to the Big Bang and the origin of our universe," Grindlay wrote in an editorial accompanying a new study of the burst in the Sept. 10 issue of the journal Nature.

This means that the explosion happened 3 billion years before the sun or Earth even formed, Grindlay added.

When astronomers see such distant objects, they are in effect looking back in time.

After the Swift detection, telescopes around the world were alerted and trained their eyes onto the new gamma-ray burst, giving scientists a highly detailed view of these explosions — the most luminous in the universe — whose formation and structure still hold many mysteries.

The findings in the new study of GRB 080319B challenge some of the commonly-held views of gamma-ray bursts.

A violent death and birth

Gamma-ray bursts are something of an extreme form of supernovas, the bright explosions that mark the deaths of massive stars.

But possibly one in every 1,000 supernovae is not one of these "normal" explosions.

Instead of the star simply dying, its core collapses to form a black hole — which generates a gamma-ray burst. (Just what the conditions are that boost a normal supernova into a gamma-ray burst are not known.)

The gamma-ray burst is actually a powerful jet of material sent out by the spinning accretion disk that surrounds a newborn black hole.

This bright part of the burst typically only lasts between 3 and 100 seconds, and an afterglow follows that can last for days or weeks.

GRB 080319B's jet was one of the brightest ever observed in terms of gamma rays, and it was unusually bright in optical wavelengths.

"It was unexpected that it was this bright," said lead author of the new study Judith Racusin, a graduate student at Penn State University.

Narrow jet

The study suggests that the jet of the gamma-burst actually has two components: a narrow, ultra-fast jet at the core of a wider, slightly slower jet.

The narrow part of the jet of GRB 080319B was so fast that it shot material directly toward Earth at 99.99995 percent the speed of light.

Scientists think that it was because the jet was pointed straight at us that it appeared so much brighter than previously-observed gamma-ray bursts.

The researchers speculate that it is rare to detect the inner core of the jet because it is so narrow — only about 1/100th the size of the full moon as seen from Earth.

For this reason, astronomers think they may have missed the narrow core of the jet in previous bursts:

"We're primarily just seeing the outer jet," Grindlay told SPACE.com, because we are not seeing those bursts head-on.

Racusin said that it isn't know for sure that all gamma-ray bursts have this two component structure to their jets, but that the theory fits what they saw with GRB 080319B.

To see a similarly bright burst, astronomers would have to catch another one aimed directly at Earth, which Racusin and her colleagues calculated should happen about once ever three to 10 years.

Swift may not still be around in 10 years, but the recently launched GLAST satellite (recently renamed Fermi) and other missions in the planning stages could catch a glimpse of them.

But whether or not they do, Racusin knows one thing: With GRB 080319B, "we got lucky."

http://www.FoxNews.com

....Pretty cool stuff!

[GamePro 55]

cool stuff

[keithlewis]

WASHINGTON (Reuters) – A privately owned U.S. communications satellite collided with a defunct Russian satellite in the first such collision in space, a U.S. military spokesman said on Wednesday.

The collision, which took place on Tuesday in low-earth orbit, involved a spacecraft of privately owned Iridium Satellite LLC and a "non-operational" Russian communications satellite, said Air Force Lieutenant Colonel Les Kodlick of the U.S. Strategic Command.

"We believe it's the first time that two satellites have collided in orbit," he said.

The command's Joint Space Operations Center was tracking 500 to 600 new bits of debris, some as small as 10 centimeters (3.9 inches) across, in addition to the 18,000 or so other man-made objects it has catalogued in space, Kodlick said.

The collision occurred at roughly 780 kilometers (485 miles), an altitude used by satellites that monitor weather and carry telephone communications among other things, he said.

"It's a very important orbit for a lot of satellites," he said.

The International Space Station flies at a lower altitude and is the command's No. 1 priority in attempting to prevent collisions, Kodlick said.

[keithlewis]

These pictures show all of the shit floating around the atmosphere

100%,600

[Blaze In Time]

it looks like that scene from wall-e

[keithlewis]

They use Spatulas for repair?

100%,500

[broncofan]

Great Article

100%,500

[BreakingBacks]

Black holes balance the books when gobbling mass

An astrophysical balancing act occurs in one of the brightest X-ray sources within our own galaxy. Astronomers from Harvard postulate that two distinct mechanisms carry mass away from a black hole that is devouring its companion star: relativistic jets and a cosmological wind.

Supermassive black holes are often accompanied by two things: an accretion disk of matter in its death throws and a pair of relativistic jets that eject some of this matter in a last-minute pardon prior to its removal from the universe. While black holes are known for capturing every bit of matter or energy that gets too close, it has also been theorized that they will eventually stop growing. It is believed that these two phenomena—matter being devoured at the edge of the disk while being pushed away by the jets—form a sort of self-regulating system that keeps these monsters in check.

While this self-regulatory behavior is believed to be common in supermassive black holes, the extreme mass scales involved mean that the dynamics of the system occur on extremely long time scales, on the order of tens of thousands of years. However, if the black hole is smaller—on the order of a few solar masses—then the dynamics of these phenomena should operate on more earthly timescales, such as a few hours. It's worth checking, because if these phenomena are not detected in smaller black holes, then physics has a big problem on its hands, since the same equations describe both sizes of black holes.

Using seven years of observations by the Chandra X-Ray observatory, a pair of astronomers from Harvard have shown that the same physics hold true in both cases. As described in the current edition of Nature, they studied GRS 1915+105, a stellar mass black hole complete with relativistic jets. This object can be described as a microquasar, a small-scale version of an active galactic nucleus.

The astronomers have identified a dynamic balancing act taking place between the relativistic jets and a hot wind blowing off the accretion disk. GRS 1915+105 is a 14 solar mass black hole that is accompanied by—and is eating—a 0.8 solar mass star that orbits it every 33.5 days. Early observations of GRS 1915+105 found it to be something special: it was the first object ever identified to have matter leaving it with speeds that appear faster than light.

Given its significance, many observatories have focused on it and researchers have found over 14 distinct classes of energetic output thought to be the result of different types of disk-jet interactions. Using data from April 2000 through August 2007, the astronomers were able to observe five of the 14 classes of X-ray emissions, and were able to lump them into two general states—hard and soft. In the 11 distinct observations of GRS 1915+105 that were made over this time period, the duo identified five observations of the various bright, soft states, and six of the faint, hard-jet-producing states.

Using an examination of the emission spectra of GRS 1915+105 during these different states, the authors postulate that a broad Fe XXV emission line is produced when the "hard" X-rays hit the inner edge of the accretion disk. Through calculations, they were able to deduce the position of the inner edge of the accretion disk during this phase, placing it around 250 times the Schwarzchild radius of the black hole. During the bright, soft states, the inner edge of the accretion disk may lie as close as three Schwarzchild radii to the black hole.

Through these observations, the pair concludes that these emission lines originate in an accretion disk wind. For a wind to occur, some driving force must exist behind it, giving it a push. The obvious candidate in such a situation would be radiation pressure, but astrophysical calculations show that radiation pressure alone would to insufficient to impart enough momentum to drive this wind. The remaining push can, however, come from X-Ray heating and thermal pressure. Sample calculations confirm that a thermal driving force, assisted by radiation pressure, can successfully produce this mighty wind.

The researchers calculated that the wind is capable of carrying away approximately 10-8 solar masses worth of material each year. The rate at which the wind drives mass away from the black hole is interesting, because it is approximately the same rate of mass driven away via the relativistic jets. This is doubly interesting because it suggests that the black hole is able to maintain a balance of mass coming in and mass going out, regardless of the mechanism by which mass leaves the system—jet or wind.

The authors conclude by stating that these observations give "a strong indication that like their supermassive counterparts, stellar-mass black holes can regulate their accretion rate by feedback into their environments." They also reiterate the importance of the finding that the high intensity of the radiation field from the disk is able to re-direct the accretion flow away from the relativistic jet, and into the outward bound wind: "our results point to fundamental new insights into the long-term disk-jet coupling around accreting black holes and hint at tantalizing evidence of the mechanism by which stellar-mass black holes regulate their own growth." This reassures us that the equations that describe gravity do indeed work at the vastly different length and time scales that exist between stellar mass and supermassive black holes.



http://arstechnica.com/science/news/200 ... s-tale.ars



Some kickass shiznit in the galaxy!