Scientists find hole in Earth’s magnetic field

Recent satellite observations have revealed the largest breach yet seen in the magnetic field that protects Earth from most of the sun’s violent blasts, researchers reported Tuesday.

The discovery was made last summer by Themis, a fleet of five small NASA satellites.

Scientists have long known that the Earth’s magnetic field, which guards against severe space weather, is similar to a drafty old house that sometimes lets in violent eruptions of charged particles from the sun. Such a breach can cause brilliant auroras or disrupt satellite and ground communications.

Observations from Themis show the Earth’s magnetic field occasionally develops two cracks, allowing solar wind — a stream of charged particles spewing from the sun at 1 million mph — to penetrate the Earth’s upper atmosphere.

Last summer, Themis calculated a layer of solar particles to be at least 4,000 miles thick in the outermost part of the Earth’s magnetosphere, the largest tear of the protective shield found so far.

"It was growing rather fast," Themis scientist Marit Oieroset of the University of California, Berkeley told an American Geophysical Union meeting in San Francisco.

Such breaches are temporary, and the one observed last year lasted about an hour, Oieroset said.

Solar flares are a potential danger to astronauts in orbit but generally are not a risk to people on the surface of the Earth.

The research was funded by NASA and the National Science Foundation.

Scientists initially believed the greatest solar breach occured when the Earth’s and sun’s magnetic fields are pointed in opposite directions. But data from Themis found the opposite to be true. Twenty times more solar wind passed into the Earth’s protective shield when the magnetic fields were aligned, Oieroset said.

The Themis results could have bearing on how scientists predict the severity of solar storms and their effects on power grids, airline and military communications and satellite signals.

The Themis satellites were launched to find the source of brief powerful geomagnetic disturbances in the Earth’s atmosphere.

Space Rocks Could Reseed Life on Earth

Asteroid and comet impacts on Earth can cause catastrophic extinction events. They can also bring life back, new research shows.

Many scientists believe that a massive rock from space came crashing down 65 million years ago at the end of the Cretaceous Period. The resulting blast set forests ablaze. The skies of Earth were filled with ash that blocked out the sun, and the planet went cold. Vegetation died in the absence of sunlight. Shortly thereafter, the dinosaurs and many other life forms on Earth went extinct. Millions of years of evolution were wiped clean in an instant.

It's frightening that one instantaneous event could completely change the face of life on Earth. However, a new study supports longstanding suggestions that asteroid impacts could also help spread life throughout the universe.

Rocks that are ejected from the Earth — or any other life-bearing planet — by an asteroid impact might actually protect microbes living inside them while they float through space. These rocks could then fall to the surface of other planets, or even back to their planet of origin.

In this way, the microbes could return to their home planet and "re-colonize" the surface after the disastrous effects of the asteroid impact have worn off.

Blast off

In order for organisms to survive a trip into orbit, they must endure a series of life-threatening events.

First there's the asteroid impact itself. Then there's the force of being launched into space. Next, they must travel in the harsh environment of space until a planet's gravity reels them in. This means facing an environment of extreme cold, intense radiation and vacuum exposure. Finally, they need to fall down through the atmosphere, experiencing extreme pressure, heating and the shock of landing.

Previous studies have shown that some rock-inhabiting organisms, known as "endoliths," might be able to survive a trip through space and a plunge through a planet's atmosphere to the surface. However, nobody knew whether these organisms could survive the initial trip into space.

Recently, an international team of researchers, led by Gerda Horneck of the Institute of Aerospace Medicine in Köln, Germany, selected a number of hardy microbes from Earth and tested their ability to hitchhike aboard rocks similar to martian meteorites.

The organisms used in the study included bacterial endospores, endolithic cyanobacteria and lichens. This selection provided a wider range of organisms than in other studies performed to date, including not just simple bacteria but also more complex eukaryotic organisms.

Smashing life

The researchers looked at previous studies of martian meteorites that provided information about the kinds of forces needed to eject rocks from a large planet. Using this data, the researchers developed a series of tests designed to simulate these pressures on the selected organisms.

By smashing the life-containing rocks between metal plates, the researchers were able to determine which organisms are capable of surviving different pressures caused by asteroid impacts and ejection into space. Ultimately, they discovered that a wide range of organisms would be capable of surviving impacts on Mars or Earth.

"Our results enlarge the number of potential organisms that might be able to reseed a planetary surface after early very large impact events, and suggest that such a re-seeding scenario on a planetary surface is possible with diverse organisms," the researchers report.

The research is detailed in the Spring 2008 issue of the journal Astrobiology.

How to land a spacecraft on an asteroid

NASA is exploring the possibility of sending astronauts to an asteroid, with hopes of making deep-space exploration more feasible.
The DigitalSpace Commons, a Santa Cruz, Calif.-based company that develops an open-source 3D rendering system, has come up with the design for a new NASA spacecraft and a mission that could eventually allow humans to land on and explore an asteroid, or so-called near-Earth objects (NEO). The privately held company plans to unveil the design publicly Monday.
The project dovetails with NASA's Constellation Program, a plan to send astronauts back to the moon by 2020. Along with the lunar mission, the space agency is investigating the possibility of using its future crew navigation vehicle for missions to an asteroid, which could help scientists better understand the minor planets or assist in eventually getting humans to Mars. Over the last six months, NASA studied how it might modify its own lunar vehicle for trips to NEOs and found that it was feasible, according to David Morrison, a senior scientist in NASA's Astrobiology Institute.
"The concept of human flights to near-Earth objects is exciting for science, and it's a logical, technological stepping stone to Mars because it's intermediate in flight length," said Morrison. "It's not literally on the way, but it's on the way for developing the technology for deep space."
Last summer, DigitalSpace said NASA asked it to develop a simulation for such a mission that would draw on the Constellation Program's spacecraft architecture. DigitalSpace's simulations attempt to deal with the unique nature of landing on an NEO.
For starters, gravity is almost non-existent on an asteroid, which can be as small as only a few hundred feet across or as big as tens of miles in diameter. And because asteroids have rocky, sometimes crumbly surfaces, DigitalSpace's proposed spacecraft includes a system that would anchor it like a boat in a harbor. The design includes a ring of airbags with sensors to detect the stability of the ground. Once a landing is deemed secure, barbed tethers would deploy to latch the craft onto the surface of the NEO. Like car airbags, the ship's airbags would compress against an asteroid's surface.
"On an asteroid, it's a different environment that requires a whole new way to land a spacecraft," said Bruce Damer, president and CEO of DigitalSpace. "It's like insects being blown around by the wind; they have all this technology to hold onto your arm."
A large part of the interest in asteroids is self-preservation, given that they have hit Earth in centuries past, causing mass destruction. In 1908, for example, a meteor struck the deep woods in Siberia, unleashing the energy equivalent of a 10- to 15-megaton atomic bomb. As a result, scientists want to study the composition and behavior of asteroids and better predict their trajectories. Morrison said scientists have only discovered a small fraction of the millions of asteroids that could be potential hits.
In addition, asteroids are composed of materials that could be useful for replenishing supplies on lengthy missions into space far in the future.
"In the long term, we don't know enough about asteroids and how much it would take to use them for resources," said Morrison.
He said the problem with traveling to an asteroid is finding one with an orbit that's similar to Earth's, so that astronauts could get there and back in a short period of time, less than roughly three months. NASA needs to conduct surveys to find a suitable asteroid for travel, he said, but DigitalSpace projects that such a flight with NEO targets could be feasible by 2017.
NASA's feasibility study looked at altering its lunar crew-exploration vehicle for an NEO mission in such a way that it would hold fewer astronauts (to make room for sufficient supplies) and include a different configuration of launch rockets, according to Morrison.
DigitalSpace then came up with a detailed configuration that could deal with the unique conditions of an asteroid, giving a better picture of how it might be done.
"We wanted to show the world how you might do a human mission to an asteroid," said Damer.

Why weather in space affects your cell phone

Your car's navigation system and your cell phone stop working. Your flight to Hong Kong has to detour to Anchorage to refuel.

In the Gulf of Mexico, hundreds of oil drilling operations stop work. And highway construction is delayed - again - because the workers can't pour concrete.

Blame it all on the weather -- in space.

Scientists and industry officials say fluctuations in space weather due to solar flares and radiation storms can cause wide-ranging problems that affect Global Positioning System devices everywhere. While the everyday GPS user will likely experience only a minor inconvenience, industries that rely on precise positioning can lose hundreds of thousands of dollars a day, or more.

It's all a bit technical, but when the sun flares, it sends out a magnetic disturbance that reaches and distorts Earth's magnetic field, said Ernie Hildner of Boulder, who retired in 2005 after nearly 20 years as director of the National Oceanic and Atmospheric Administration's Space Environment Center. Other types of space weather include radiation and geomagnetic storms.

Hildner spoke at a seminar on space weather this week on Capitol Hill, where Rep. Mark Udall, D-Colo, said he has fought to keep federal funding for the Space Environment Center. Its budget has shrunk over the past few years.

"We can't control it, but we can predict and understand it," Udall said of space weather. When an audience member, Len Pietrafesa, a professor of Oceanic and Atmospheric Sciences at North Carolina State University, said the Space Environment Center needs more funding, Udall said he would consider it a homework assignment.

The center studies solar flares and warns the world when disturbances are expected to be high. Airlines and drilling industries, among others, take those warnings seriously, changing flight paths or delaying operations until storms are over.

Although space weather has affected human technology as far back as the first telegraph wires, the widespread use of new systems based on GPS satellites leaves communications and other links more vulnerable to the sun's eruptions than ever before.

Coincidentally, GPS has risen in popularity during the quietest years of the 11-year cycle of solar flares.
While 2007 is a low point in the cycle, the center predicts it will start to rise in 2008, peaking sometime from 2011 to 2013.

More industries than ever rely on GPS for precise positioning. Airlines have created more flight routes that cross the North Pole, cutting down on fuel costs and travel time. Oil drilling and mining companies use the system for such details as where they can anchor rigs. Highway construction companies and farms use GPS to perfect tiny details of daily operations.

So when space storms are brewing, they pay close attention to the center's readings. For airlines, days with high solar activity often require changing their polar routes, from Chicago and New York to cities in China and India, because of increased risk of lost communications with ground controller and radiation levels which are higher at high altitudes near the poles, said Gene Cameron, manager of worldwide support for United Airlines.

Richard Barker, systems engineering manager for Fugro Chance Inc., a marine survey company, said he recommends oil drilling operations stop when there's a risk of GPS going out. Though companies can lose up to $1 million a day when they don't work, they risk damaging oil pipelines and underwater infrastructure without the exact measurements GPS provides.

The cost of solar activity is enormous, the three men who spoke at the seminar said. Hildner said the National Academy of Sciences will study the costs of space weather, but so far no authoritative estimate exists. The direct cost to an industry like United Airlines, which would lose money by grounding or changing a flight, would snowball for customers who would miss connecting flights or business meetings.

Source : Scripps Howard News Service

Inside The Turbulent Sun

To the non-astronomer, the Sun is a model of constancy - a featureless white globe that has shone steadily throughout human history. But astronomers know the Sun to be a nuclear powerhouse in constant turmoil, and it may be far less reliable than we think.


The Sun is a vast ball of hot gas, principally hydrogen, big enough to swallow up 1.3 million Earths. To express its weight in tonnes you would need to write a 2 followed by 27 noughts. This weight, some 3000 000 times that of the Earth, crushes the Sun's core to a pressure of over 300 million times that of our atmosphere.


The temperature at the centre of the Sun is 15 000 000 degree C (27 000 000 degree F). In this furnace rages the nuclear reaction that creates the Sun's light and heat. It is the same reaction that powers the H-Bomb - the nuclear 'burning' of hydrogen into helium. As in all nuclear reactions, matter is converted into energy. The amount of helium produced in the reaction is only 92.3 per cent of the amount of hydrogen used up. The difference has been converted into light, heat, X-rays and other forms of energy. Four million tonnes of the Sun's matter vanish in this way each second.


At the surface, the Sun's temperature is a mere 5800 degree C (10 400 degree F). The visible surface is mottled - bright where hot gas has just risen from the depths, darker where a cooled area is about to descend. Invisible, looping magnetic fields occasionally break through the surface from the depths beneath. The magnetic fields block the flow of energy, so the areas of the surface where the loops emerge and re-enter become relatively cool and appear as dark sunspots. Prominences - spectacular clouds of glowing red hydrogen many times the size of the Earth - climb into the solar sky and fall back again.


Can a body as violent as the Sun be relied upon not to change its behaviour in the future - not to scorch us or let us freeze to death?


Constant monitoring shows many irregularities. It appears, for example, that since 1979 the Sun has cooled by one-tenth of 1 per cent. This minor fluctuation will probably reverse, staying in step with regular ups and downs in general solar activity, such as the number of sunspots. All theorists agree that the Sun will continue to support life on Earth for about another 5000 million years.

Bombardment From The Sun

On July 7, 1988, 3000 homing pigeons fluttered from cages in northern France, circled a few times and set off on their annual race for their homes in southern England. But events on the distant Sun were to doom the race.


Two days before, a solar flare - a colossal explosion on the surface of the Sun - had fired clouds of electrically charged protons and other subatomic particles into space, some of which had disrupted the Earth's magnetic field. When bad weather prevents them from steering by the Sun or the stars, homing pigeons use internal magnetic 'compasses' to guide them. Misled by the celestial disturbances, the pigeons flew way off course. Few made it to their homes.


Pigeons are not the only creatures at risk from solar flares. The high-energy particles they fire out pose a serious risk of radiation sickness and even cancer to space travellers. Space shuttle flights are postponed whenever astronomers observe a flare. If astronauts one day build bases on the Moon or Mars they may need to cover them with rocks as protection against the radiation emitted by solar flares. And long-distance manned spacecraft will have to be equipped with 'storm shelters' for the crew to retreat into when flares occur.

Asteroids - Vermin Of The Skies

Asteroids, also called minor planets or planetoids. They are so numerous that they have earned the name 'Vermin of the Skies'. Hundreds of thousands of asteroids have been discovered within the solar system and the present rate of discovery is about 5000 per month. The largest is Ceres, 1003 km (623 miles) in diameter, followed by Pallas at 608 km (378 miles) and Vesta at 538 km (334 miles). Only Vesta occasionally comes close enough to Earth to become visible - if only just - to the naked eye.


Asteriods were originally given classical names, but as more have been discovered, more inventive names have been devised. Asteroid number 694 is called 'Ekard' - its orbit was computed by students of Drake University, Iowa, and Ekard is Drake reversed. Asteroid 1625 is called 'The NORC', after an early electronic computer, the Naval Ordnance Research Calculator. 'Hapag' is named after a German shipping line, the Hamburg-Amerika Packetfahrt Aktien Gesellschaft. 'Bettina' is named after the wife of Baron Albert von Rothschild, who bought the right to name the asteroid. Four asteroids discovered in the 1980s have been named after the members of the Beatles.