Posted on 02/18/2005 6:11:56 PM PST by Servant of the 9
A huge explosion halfway across the galaxy packed so much power it briefly altered Earth's upper atmosphere in December, astronomers said Friday. No known eruption beyond our solar system has ever appeared as bright upon arrival. But you could not have seen it, unless you can top the X-ray vision of Superman: In gamma rays, the event equaled the brightness of the full Moon's reflected visible light. The blast originated about 50,000 light-years away and was detected Dec. 27. A light-year is the distance light travels in a year, about 6 trillion miles (10 trillion kilometers). The commotion was caused by a special variety of neutron star known as a magnetar. These fast-spinning, compact stellar corpses -- no larger than a big city -- create intense magnetic fields that trigger explosions. The blast was 100 times more powerful than any other similar eruption witnessed, said David Palmer of Los Alamos National Laboratory, one of several researchers around the world who monitored the event with various telescopes. "Had this happened within 10 light-years of us, it would have severely damaged our atmosphere and possibly have triggered a mass extinction," said Bryan Gaensler of the Harvard-Smithsonian Center for Astrophysics (CfA). There are no magnetars close enough to worry about, however, Gaensler and two other astronomers told SPACE.com. But the strength of the tempest has them marveling over the dying star's capabilities while also wondering if major species die-offs in the past might have been triggered by stellar explosions. 'Once-in-a-lifetime' The Sun is a middle-aged star about 8 light-minutes from us. It's tantrums, though cosmically pitiful compared to the magnetar explosion, routinely squish Earth's protective magnetic field and alter our atmosphere, lighting up the night sky with colorful lights called aurora. Solar storms also alter the shape of Earth's ionosphere, a region of the atmosphere 50 miles (80 kilometers) up where gas is so thin that electrons can be stripped from atoms and molecules -- they are ionized -- and roam free for short periods. Fluctuations in solar radiation cause the ionosphere to expand and contract. "The gamma rays hit the ionosphere and created more ionization, briefly expanding the ionosphere," said Neil Gehrels, lead scientist for NASA's gamma-ray watching Swift observatory. Gehrels said in an email interview that the effect was similar to a solar-induced disruption but that the effect was "much smaller than a big solar flare." Still, scientists were surprised that a magnetar so far away could alter the ionosphere. "That it can reach out and tap us on the shoulder like this, reminds us that we really are linked to the cosmos," said Phil Wilkinson of IPS Australia, that country's space weather service. "This is a once-in-a-lifetime event," said Rob Fender of Southampton University in the UK. "We have observed an object only 20 kilometers across [12 miles], on the other side of our galaxy, releasing more energy in a tenth of a second than the Sun emits in 100,000 years." Some researchers have speculated that one or more known mass extinctions hundreds of millions of years ago might have been the result of a similar blast altering Earth's atmosphere. There is no firm data to support the idea, however. But astronomers say the Sun might have been closer to other stars in the past. A similar blast within 10 light-years of Earth "would destroy the ozone layer," according to a CfA statement, "causing abrupt climate change and mass extinctions due to increased radiation." The all-clear has been sounded, however. "None of the known sample [of magnetars] are closer than about 4,000-5,000 light years from us," Gaensler said. "This is a very safe distance." Cause a mystery Researchers don't know exactly why the burst was so incredible. The star, named SGR 1806-20, spins once on its axis every 7.5 seconds, and it is surrounded by a magnetic field more powerful than any other object in the universe. "We may be seeing a massive release of magnetic energy during a 'starquake' on the surface of the object," said Maura McLaughlin of the University of Manchester in the UK. Another possibility is that the magnetic field more or less snapped in a process scientists call magnetic reconnection. Gamma rays are the highest form of radiation on the electromagnetic spectrum, which includes X-rays, visible light and radio waves too. The eruption was also recorded by the National Science Foundation's Very Large Array of radio telescopes, along with other European satellites and telescopes in Australia. Explosive details A neutron star is the remnant of a star that was once several times more massive than the Sun. When their nuclear fuel is depleted, they explode as a supernova. The remaining dense core is slightly more massive than the Sun but has a diameter typically no more than 12 miles (20 kilometers). Millions of neutron stars fill the Milky Way galaxy. A dozen or so are ultra-magnetic neutron stars -- magnetars. The magnetic field around one is about 1,000 trillion gauss, strong enough to strip information from a credit card at a distance halfway to the Moon, scientists say. Of the known magnetars, four are called soft gamma repeaters, or SGRs, because they flare up randomly and release gamma rays. The flare on SGR 1806-20 unleashed about 10,000 trillion trillion trillion watts of power. "The next biggest flare ever seen from any soft gamma repeater was peanuts compared to this incredible Dec. 27 event," said Gaensler of the CfA.
No.
She's sitting next to Einstein, which makes sense, I guess. They're both very successful in their chosen fields.
One other cute image there, with equations on a chalkboard behind her. Surreal and funny. They are in wallpaper formats.
Very nice site. Britney is used to make it more interesting to young students, probably.
Thank you for your response. I am not insisting my theory is correct. It is just my theory. I am always looking for new information which can tell me if my theory(s) are wrong.
I learn so much more from being wrong, than from being right.
Is is possible that a neutron star could undergo some other kind of transformation (other than the supernova phase) that we are not aware of yet that would allow this possibility?
I know that is kind of a self-supporting and unanswerable question, unless you can provide me with a good NO answer.
Which wouldn't bother me. Always happy to find the truth, whatever it may be.
Funny, for all of our perception of Britney being the stereotypical example of a 'dumb blonde', you would be surprised at how intelligent she actually is. (well, except for her dealings with matrimony!)
bump
Does this mean all our neighbors on the other side of the galaxy were wiped out?
My theory was that life capable planets have this type of core, non life capable planets do not.
So, until we can determine if those planets can and/or do support life, I couldn't say for sure.
My guess, is yes.
Mars, maybe.
Venus, probably.
Pluto, no. (don't think it is really a planet anyway. )
Mercury, no. (mercury, same category as pluto)
Those are my guesses. And truly, it is all idle speculation.
No. Dark matter is.
Brin is a hard Science Fiction writer, and also a professor of Astrophysics. I imagine you can take his description of the results of a black hole impinging on Earth as gospel.
So9
The earth is much too light to have a neutron star at its core. By definition neutron stars have the mass of stars, and surface gravities that go with that mass and radius. The earth doesn't have that sort of surface gravity, even given the much larger than a neutron star radius. Thus there is no neutron start at the earth's core. Rather a large ball of nickle-iron.
According to Einstein, yes. As far as we know today the answer is still yes. However there are beginning to be cracks in that theory, or at least ways around the limitation are beginning to show themselves.
No, not if it was 10 light years away. The radiation would not reach the ground, and the heat might not propagate to the surface either. It would be more easily noticed at night if there were no clouds.
The quote from the article claimed there would be mass extinction due to the ozone layer being damaged, but that is not really possible. The ozone layer is caused by UV (sunlight) disassociating oxygen molecules in the upper atmosphere.
If you still have sunlight and oxygen, you will have ozone.
Another G'ould Mothership bites the dust...
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