Huge Defunct Satellite Falling to Earth Faster Than Expected, NASA Says

(source: space.com)

NASA space junk experts have refined the forecast for the anticipated death plunge of a giant satellite, with the U.S. space agency now predicting the 6 1/2-ton climate probe will plummet to Earth around Sept. 23, a day earlier than previously reported.
The defunct bus-size spacecraft is NASA's Upper Atmospheric Research Satellite (UARS), which launched in 1991 and was shut down in 2005 after completing its mission. The satellite was expected to fall to Earth sometime this year, with experts initially pegging a weeks-long window between late September and early October, then narrowing it to the last week of this month.
That window, NASA now says, has been trimmed to just three days.
"Re-entry is expected Sept. 23, plus or minus a day. The re-entry of UARS is advancing because of a sharp increase in solar activity since the beginning of this week," NASA officials wrote in a status update today (Sept. 16). The projection is a day earlier than a previous forecast released by NASA yesterday.
NASA spokeswoman Beth Dickey confirmed with SPACE.com earlier today that the reason UARS is expected to fall early in its re-entry window is because of the sharp uptick in solar activity. Solar effects from the sun can create an extra drag on satellites in space because they can heat the Earth's atmosphere, causing it to expand, agency officials have said.



Star Smile mad

Blazing UFO sparks panic as it shoots across 250 miles of night sky above California

(source: dailymail.co.uk)

When a streak of fire blazed through the air above southern California, people could have been forgiven for thinking the Earth was under attack. Thousands saw it from Phoenix in Arizona to Las Vegas and Los Angeles and local authorities were swamped with reports of ball of flame in the night sky. One witness said: 'It was huge. It had a green glow in front of it and a white tail. It looked like green fireworks going across the sky.' But experts have revealed the phenomenon was most likely a fireball - a fragment of an asteroid that entered Earth's atmosphere.
The light was seen shooting quickly from west to east at around 7.45pm PDT, or 2.45am GMT.
Many reported it as bluish-green and others as yellow and orange. Some captured video of the object.
NASA scientist Don Yeomans, who runs the agency's Near-Earth Object Program, said: 'We can't say 100 per cent, but it's almost certain that the object was a fireball or very bright meteor the size of a basketball or baseball that likely disintegrated before it hit the ground.'
According to Mr Yeomans, the bluish-green colour suggests the object had some magnesium or nickel in it.
He added that orange is usually an indication it is entering earth's atmosphere at several miles per second, a moderate rate of speed.
'They make an impressive show for such a small object,' Mr Yeomans said.
Yeomans said fireball events are much more rare than shooting stars, but they happen on a weekly basis somewhere on Earth, usually over the ocean.
'It's a natural phenomenon and nothing to be concerned about.'
Astronomer Dennis Mammana, from Borrego Springs, said: 'Apparently this one put on a big show.
'The color of the object can tell you about the chemical composition of the meteor. The bluish-green color could mean it was nickel.'
At Maricopa County Sheriff's Office police fielded more than a dozen calls about sightings.
Sheriff's deputies at Deer Valley Airport in north Phoenix reported a sighting themselves, Lieutenant Justin Griffin said.
'It took an unusually long time to get across the sky,' Lt Griffin said. 'It's like a meteor. It's not like we had any flying objects with little green men or anything like that.'
Sergeant Steve Martos, of the Phoenix Police Department, said his agency received four calls 'regarding the light in the sky'.
He added: 'Myself and other officers observed it as well. We all made our wishes and went back to work. Nothing more to report. Have a safe night.'
The burning object also created a stir on Twitter.
One witness tweeted: 'I saw a lot of red in it from my vantage point in Phoenix, as well as the blue and green tail.
Another tweeted: 'It was CRAZY! Green and going fast & then it just burned out.'
Federal Aviation Administration spokesman Ian Gregor has confirmed there were no aircraft incidents reported in the Western region.




Star Smile mad

Star eaten by a black hole: still blasting away

(source: blogs.discovermagazine.com)

In late March of 2010, an extraordinary event occurred: a black hole in a distant galaxy tore apart and ate a whole star.
Now, there’s more info: the black hole, lying at the center of a galaxy nearly 4 billion light years away, has about 8 million times the mass of the Sun. When it tore the star apart, about half the mass of the star swirled around the black hole, forming twin beams of matter and energy that blasted outward at a large fraction of the speed of light. The folks at NASA’s Goddard Space Flight Center made a great animation to show this:



The star was ripped apart by tides. The thing about black holes is, they’re small: this one was probably about 15 million kilometers across. A typical star is about a million km across (the Sun is 1.4 million kilometers in diameter, for comparison). This means the star could get really close to the black hole, and that’s why it was doomed. The force of gravity drops with distance, so as the star approached, the side of it facing the black hole felt a far greater force than the size facing away. That stretched the star, and the stretching increased as the star got closer. At some point, the force was so great it exceeded the star’s own gravity, and it could no longer hold on to its material. The black hole won — as they usually do.


The material from the shredded star formed a disk around the black hole, and near the center heated up to millions of degrees as it swirled around at near the speed of light. For reasons not entirely understood, this forms the beams of matter that jet away from the hole, and as it happens one of these beams was aimed pretty much right at us (not to worry, though, since at that vast distance the light was so diminished it took Hubble to see it in visible light at all). That’s what alerted us to the event in the first place; it was detected by the Swift satellite, which was designed to look for high-energy blasts from space.
Normally, things like this fade pretty quickly, but in this case, amazingly, it’s still pouring out energy and will probably be detectable even into 2012. That is partly due to relativity: because we’re looking straight down the beam of material, we see its clock ticking more slowly. This effect works better when the material is moving at high speed, and radio observations show that the blast is still expanding away from the black hole at half the speed of light! And that’s after it slowed down by ramming into material floating in between the stars in that galaxy. It started out moving at more than 90% the speed of light.
The energy it takes to do this is mind-numbing: we’re talking about roughly an octillion tons of matter screaming outward at well over one hundred thousand kilometers per second!
It literally makes the hair on the back of my neck stand up. I’m glad this happened billions of light years away.
Astronomers will continue to observe this event to learn more about it. It probably happens all the time in the Universe, but this is the first time we’ve had the equipment to really get a good look (even if we have to crane our necks a bit from 4 billion light years away). We’re not really sure how often something like this happens, or how it affects the galactic environment. I’ll note I’m not terribly worried about it happening in our Milky Way (we have a 4 million solar mass black hole in the center of our galaxy), since, after all, we’re here. If this happened often enough to be dangerous, we wouldn’t be here to talk about it!



Star Smile mad

More Active Sun Means Nasty Solar Storms Ahead

(Source: Yahoo News)

The sun is about to get a lot more active, which could haveill effects on Earth. So to prepare, top sun scientists met Tuesday to discuss thebest ways to protect Earth's satellites and other vital systems from the comingsolar storms.
Solar storms occur when sunspots on our star erupt and spewout flumes of charged particles that can damage power systems. The sun'sactivity typically follows an 11-year cycle, and it looks to be coming out of aslump and gearing up for an active period.
"The sun is waking up from a deep slumber, and in thenext few years we expect to see much higher levels of solar activity,"said Richard Fisher, head of NASA's Heliophysics Division. "At the sametime, our technological society has developed an unprecedented sensitivity to solarstorms. The intersection of these two issues is what we're getting togetherto discuss."
Fisher and other experts met at the Space Weather EnterpriseForum, which took place in Washington, D.C., at the National Press Club.
Bad news for gizmos
People of the 21st century rely on high-tech systems for thebasics of daily life. But smart power grids, GPS navigation, air travel,financial services and emergency radio communications can all be knockedout by intense solar activity.
A major solar storm could cause twenty times more economicdamage than Hurricane Katrina, warned the National Academy of Sciences in a2008 report, "Severe Space Weather Events—Societal and EconomicImpacts." [Photos:Sun storms.]
Luckily, much of the damage can be mitigated if managersknow a stormis coming. That's why better understanding of solar weather, and theability to give advance warning, is especially important.
Putting satellites in 'safe mode' and disconnecting transformerscan protect electronics from damaging electrical surges.
"Space weather forecasting is still in its infancy, butwe're making rapid progress," said Thomas Bogdan, director of the NationalOceanic and Atmospheric Administration (NOAA)'s Space Weather Prediction Centerin Boulder, Colo.
Eyes on the sun
NASA and NOAA work together to manage a fleet of satellitesthat monitor the sun and help to predict its changes.
A pair of spacecraft called STEREO (Solar TerrestrialRelations Observatory) is stationed on opposite sides of the sun, offering acombined view of 90 percent of the solar surface. In addition, SDO (the SolarDynamics Observatory), which just launched in February 2010, is able tophotograph solar active regions with unprecedented spectral, temporal andspatial resolution. Also, an old satellite called the Advanced CompositionExplorer (ACE), which launched in 1997, is still chugging along monitoringwinds coming off the sun. And there are dozens more dedicated to solar science.
"I believe we're on the threshold of a new era in whichspace weather can be as influential in our daily lives as ordinary terrestrialweather." Fisher said. "We take this very seriously indeed."

Star Smile mad