NASA scientists are searching for an invisible ‘Death Star’ that circles the Sun, which catapults potentially catastrophic comets at the Earth.
The star, also known as Nemesis, is five times the size of Jupiter and could be to blame for the impact that wiped out the dinosaurs 65 million years ago.
The bombardment of icy missiles is being blamed by some scientists for mass extinctions of life that they say happen every 26 million years.
Nemesis is predicted to lie at a distance equal to 25,000 times that of the Earth from the Sun, or a third of a light-year.
Astronomers believe it is of a type called a red or brown dwarf - a “failed star” that has not managed to generate enough energy to burn like the Sun.
But it should be detectable by a heat-sensitive space telescope called WISE, the Wide-Field Infrared Survey Explorer.
Launched last year, WISE began surveying the skies in January. It is expected to discover a 1000 brown dwarfs within 25 light-years of the Sun - right on our cosmic doorstep - before its coolant runs out in October.
The nearest normal star to us is around 4.5 light-year away.
Our solar system is thought to be surrounded by a vast sphere of icy bodies, twice as far away as Nemesis, called the Oort Cloud.
Some get kicked in towards the planets as comets - giant snowballs of ice, dust and rock - and the suggestion is that the Death Star’s gravitational influence is to blame.
The paleontologists David Raup and Jack Sepkoski discovered that, over the last 250 million years, life on Earth has been devastated on a 26-million-year cycle. Comet impacts are suggested as a likely cause for these catastrophes.
A similar impact by an asteroid wiped out the dinosaurs 65 million years ago, a major inquest by scientists concluded last week, though that is not being blamed on Nemesis.
Most stars have one or more companion stars orbiting around each other, which would make the sun’s single status unusual.
A major clue to Nemesis’s existence is a mysterious dwarf planet called Sedna that was spotted on an elongated 12,000-year-long orbit around the sun.
Mike Brown, who discovered Sedna in 2003, said: “Sedna is a very odd object - it shouldn’t be there! It never comes anywhere close to any of the giant planets or the sun. It’s way, way out there on this incredibly eccentric orbit.
The only way to get on an eccentric orbit is to have some giant body kick you - so what is out there?”
Professor John Matese, of the University of Louisiana at Lafayette, says most comets in the inner solar system seem to come from the same region of the Oort Cloud - launched by the pull of a companion star to the sun that scatters comets in its wake.
He suggests it is up to five times the size of Jupiter or 7,000 times the size of Earth.
He said: “There is statistically significant evidence that this concentration of comets could be caused by a companion to the Sun.”
By Richard Alleyne, Science Correspondent
Published: 8:00AM GMT 13 Mar 2010
It's a "coronal hole," a vast region where the sun's magnetic field has opened up and allowed the solar wind to escape. Indeed, a solar wind stream flowing from this hole is heading toward Earth, due to arrive on June 7th or 8th. High latitude sky watchers should be alert for auroras on those dates.
Source: http://www.spaceweather.com
The sun is about to get a lot more active, which could have ill effects on Earth. So to prepare, top sun scientists met Tuesday to discuss the best ways to protect Earth's satellites and other vital systems from the coming solar storms.
Solar storms occur when sunspots on our star erupt and spew out flumes of charged particles that can damage power systems. The sun's activity typically follows an 11-year cycle, and it looks to be coming out of a slump and gearing up for an active period.
"The
sun is waking up from a deep slumber, and in the
next few years we expect to see much higher levels of solar activity,"
said Richard Fisher, head of NASA's Heliophysics Division. "At the same
time, our technological society has developed an unprecedented
sensitivity to solar
storms. The intersection of these two issues is what we're getting
together
to discuss."
Fisher and other experts met at the Space Weather Enterprise Forum, 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 the basics of daily life. But smart power grids, GPS navigation, air travel, financial services and emergency radio communications can all be knocked out by intense solar activity.
A major solar storm could cause twenty times more economic damage than Hurricane Katrina, warned the National Academy of Sciences in a 2008 report, "Severe Space Weather Events—Societal and Economic Impacts." [Photos: Sun storms.]
Luckily, much of the damage can be mitigated if managers know a storm is coming. That's why better understanding of solar weather, and the ability to give advance warning, is especially important.
Putting satellites in 'safe mode' and disconnecting transformers can protect electronics from damaging electrical surges.
"Space weather forecasting is still in its infancy, but we're making rapid progress," said Thomas Bogdan, director of the National Oceanic and Atmospheric Administration (NOAA)'s Space Weather Prediction Center in Boulder, Colo.
Eyes on the sun
NASA and NOAA work together to manage a fleet of satellites that monitor the sun and help to predict its changes.
A pair of spacecraft called STEREO (Solar Terrestrial Relations Observatory) is stationed on opposite sides of the sun, offering a combined view of 90 percent of the solar surface. In addition, SDO (the Solar Dynamics Observatory), which just launched in February 2010, is able to photograph solar active regions with unprecedented spectral, temporal and spatial resolution. Also, an old satellite called the Advanced Composition Explorer (ACE), which launched in 1997, is still chugging along monitoring winds 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 which space weather can be as influential in our daily lives as ordinary terrestrial weather." Fisher said. "We take this very seriously indeed."
http://www.space.com/scienceastronomy/active-sun-solar-storms-100609.html
Planet alignment raises tsunami fears
Reports that the alignment of the planets might cause a tsunami in Andaman coastal provinces have led to emergency evacuation drills being conducted on an island in Surat Thani.The drill yesterday on Rad Island in Don Sak district, located 1km from the mainland, was organised by the National Disaster Warning Centre (NDWC), the Information and Communication Technology Ministry and local authorities.
Residents received training in communications and rescue and relief efforts in the event of a tsunami.
During the exercise, 150 residents took cover in the municipal office.
The drill also included practice search and rescue operations for passengers of capsized vessels using a helicopter and a police patrol boat.
Earlier, Kongpop U-yen, a Thai engineer who works at the US National Aeronatics and Space Administration (Nasa), said the alignment of the planets today could cause natural disasters such as earthquakes and tsunamis.
NDWC chief Smith Dharmasarojana agreed with the forecast, saying it was backed by scientific data.
The forecast, however, met with criticism from the scientific community as authorities did not clarify the prediction.
Mr Smith recently said during a TV interview that a solar eclipse was due to occur on June 12 as a result of the alignment of the Earth, the moon and the sun.
He said the alignment would release considerable cumulative energy, which could affect the Earth. Mr Smith, quoting Mr Kongpop, said the phenomenon would have a direct impact on the Earth in the forms of climate disruption, earthquakes and volcanic eruptions.
As to which part of the world would be affected by the disasters, Mr Kongpop said that depended on the time the sun unleashed its energy.
It was hard to exactly locate the target area as the Earth revolved around the sun, he said.
Mr Smith said that Southeast Asia could be the first region to be affected if the planetary alignment, due to occur at 6.30pm local time, triggers natural disasters.
A 7.0-8.5 magnitude earthquake on the Richter scale could occur, possibly causing a tsunami.
"The warning is something to consider, not to be panicked about. We cannot rely 100% on any theory," Mr Smith said. But he said he believed the predicted disaster might happen.
