Skip to main content

NASA spacecraft snaps first footage of solar tsunami

Wednesday, October 14, 2009 NEW YORK: Images from the twin STEREO spacecraft show, for the first time, a solar tsunami blasting its way through the Sun's lower atmosphere. Solar tsunamis are launched by huge explosions near the Sun's atmosphere, called coronal mass ejections (CMEs). Although solar tsunamis share much in common with tsunamis on Earth, the solar version can travel at over a million kilometres per hour.The tsunami took place on 19th May 2007 and lasted for about 35 minutes, reaching peak speeds around 20 minutes after the initial blast. The observations were made by a team from Trinity College Dublin.'The energy released in these explosions is phenomenal, about two billion times the annual world energy consumption in just a fraction of a second. In half an hour, we saw the tsunami cover almost the full disc of the Sun, nearly a million kilometres away from the epicentre,' said Long.STEREO's Extreme Ultraviolet Imager (EUVI) instruments monitor the Sun at four wavelengths, which correspond to temperatures ranging between 60 000 and 2 million degrees Celsius. At the lowest of these temperatures, scientists can see structures in the chromosphere, a thin layer of the solar atmosphere that lies just above the Sun's visible surface. At temperatures between 1 and 2 million degrees Celsius, scientist can monitor features at varying levels in the solar corona.The SOHO spacecraft, which was launched in 1995, also monitors the Sun at these wavelengths but only took images four times per day, giving scientists rare snapshots of these tsunamis. STEREO's EUVI instruments take an image every few minutes to create a series, making it possible for scientists to track how the wave spreads over time.This is the first time that a tsunami has been observed at all four wavelengths, which enabled the team to see how the wave moved through the different layers of the solar atmosphere.'To our surprise, the tsunami seems to move with similar speed and acceleration through all the layers. As the chromosphere is much denser than the corona, we'd expect the pulse there to drag. It's a real puzzle,' said Dr Peter Gallagher.To complicate matters, the interval between images is not the same for all four cameras. At the time of the tsunami, the cameras monitoring radiation at 1 million degrees Celsius were set to take an image every 2.5 minutes. They recorded much higher speeds and accelerations for the wave than the other cameras, which were on 10 or 20 minute cycles. By taking a sample of one image in four, the data from these cameras matched the lower values observed in the other layers.'We've thought for some time that the tsunamis might be caused by magnetic shockwaves but, in previous snapshots, the waves appeared to be travelling too slowly. However, we've seen from this set of observations that if the time interval between images is too long, it's easy to underestimate the speed that the waves are moving. With a few more rapid-sequence observations of solar tsunamis, we should finally be able to identify the cause of these waves,' said Gallagher.

Comments

Popular posts from this blog

India's swine flu death rate is increasing

Friday, August 14, 2009 MUMBAI: A 26-year-old woman died Thursday of H1N1 swine flu in the southern city of Bangalore, raising India's death toll from the virus to 20, authorities said.The death was the first reported in India's information technology capital, the Press Trust of India reported.Meanwhile in Pune, the worst-affected in India, two more victims of the virus died Thursday, raising the death toll in that western city near Mumbai to 12, the report said. The victims were an 11-month-old boy and a 75-year-old old woman.US media reported movie halls, schools and colleges were ordered closed Thursday for three days to a week in Mumbai, the commercial and financial capital of the country, as fear of the pandemic spread.Prajakata Lavangare, a spokeswoman for the government of Maharashtra state of which Mumbai is the capital, said similar orders were issued in Pune, which is also located in the state.The woman who died in Bangalore was identified only as Roopa, a teacher in...

Suicide bombings kill 18 in Iraq

Thursday, August 13, 2009 MOSUL: At least 18 people, most of them members of the ancient Yazidi religious sect, were killed when two suicide bombers blew themselves up on Thursday in a packed cafe in northern Iraq, a local government official said.At least 31 people were also wounded after the bombers detonated suicide belts packed with explosives in the cafe in Kalaa town, in the district of Sanjar, local district chief Dakheel Qassem Hasoon, told a foreign news agency."Two suicide bombers entered the Cafe Barbaroz at 4:30 pm (1330 GMT) and blew themselves up, killing 18 civilians and wounding 31. Most of the victims were Yazidis," Hasoon said.Kalaa, northwest of the insurgent stronghold of Mosul in northern Nineveh province is predominantly populated by the minority Yazidi religious sect, as well as Arabs and Kurds.The attack is the deadliest since Monday, when 51 people were killed across Iraq, including 28 members of the tiny Shabak sect cut down when two truck bombs det...

US drones to target Taliban in Afghan war

Friday, July 31, 2009 WASHINGTON: The US military plans to use more drone aircraft to target Taliban militants in Afghanistan while focusing less on hunting down Al-Qaeda figures, report said on Thursday.Although defeating the Al-Qaeda terror network remains an overriding goal for Washington, officials now believe the best way to pursue that objective is to ensure stability in Afghanistan and neighboring Pakistan instead of Al-Qaeda manhunts, the paper said, citing US government and Defense Department officials.It was more important to prevent a slide towards violence and anarchy that could be exploited by Al-Qaeda, which used Afghanistan to stage its attacks on the United States on September 11, 2001, the officials said."We might still be too focused on Bin Laden," an official said. "We should probably reassess our priorities."The shift in priorities for the drone fleet comes despite President Barack Obama's declaration that defeating and dismantling Al-Qaeda ...