Using the Cluster spacecraft, scientists from University College London (UCL) have made the first direct observations of charged particles that lead to some of the brightest aurora. The aurora, or northern and southern lights, are caused by highly energetic charged particles, normally held in space by Earth's magnetic field, colliding with Earth's upper atmosphere.

As these high-energy particles collide with molecules in the atmosphere they lose energy, causing the atmospheric molecules to glow and heating the atmosphere. The result of is spectacular displays of shimmering curtains of red, green and blue light normally seen above the polar regions, but occasionally seen as far south as northern England.

After the most profound lull in solar activity for nearly a century, the Sun is finally coming back to life. But will the solar activity return to previous levels? ESA's venerable solar watchdog SOHO is there, watching and measuring, providing unique information about our nearest star.

It was the perfect Christmas present for solar physicists. In mid-December 2009, the largest group of sunspots to emerge for several years manifested itself on the solar surface. It occurred just as some solar physicists were beginning to wonder if large sunspots would ever return.

Take a bunch of fast-moving electrons, place them in orbit and then hit them with the shock waves from a solar storm. What do you get? Killer electrons. That's the shocking recipe revealed by ESA's Cluster mission.

Killer electrons are highly energetic particles trapped in Earth's outer radiation belt, which extends from 12 000 km to 64 000 km above the planet's surface. During solar storms their number grows at least ten times and they can be dislodged, posing a threat to satellites. As the name suggests, killer electrons are energetic enough to penetrate satellite shielding and cause microscopic lightning strikes. If these electrical discharges take place in vital components, the satellite can be damaged or even rendered inoperable.

Ever since NASA's Interstellar Boundary Explorer, or IBEX, mission scientists released the first comprehensive sky map of our solar system's edge in particles, solar physicists have been busy revising their models to account for the discovery of a narrow "ribbon" of bright emission that was completely unexpected and not predicted by any model at the time.

Further study by a team of scientists funded through NASA's Heliophysics Guest Investigator program has produced a revised model that explains and closely reproduces the IBEX result by incorporating a single new effect into an existing model. The new effect, put forward by the IBEX team soon after sighting of the ribbon, is that the magnetic field surrounding our solar system -- called the local galactic magnetic field -- acts like a mirror for the particles that IBEX sees.

Sometimes you really can believe your eyes. That's what NASA's Solar Terrestrial Relations Observatory (STEREO) is telling researchers about a controversial phenomenon on the sun known as the "solar tsunami."

Years ago, when solar physicists first witnessed a towering wave of hot plasma racing across the sun's surface, they doubted their senses. The scale of the wave was staggering: It rose up higher than Earth itself and rippled out from a central point in a circular pattern millions of kilometers in circumference. Skeptical observers suggested it might be a shadow of some kind -- a trick of the satellite's eye -- but surely not a real wave.

When NASA's Cassini spacecraft began orbiting Saturn five years ago, a dozen highly-tuned science instruments set to work surveying, sniffing, analyzing and scrutinizing the Saturnian system.

But Cassini recently revealed new data that appeared to overturn the decades-old belief that our solar system resembled a comet in shape as it moves through the interstellar medium (the matter between stars in our corner of the Milky Way galaxy).

Solar wind generated by the sun is probably driven by a process involving powerful magnetic fields, according to a new study led by UCL researchers based on the latest observations from the Hinode satellite.

Scientists have long speculated on the source of solar winds. The Extreme Ultraviolet Imaging Spectrometer (EIS), on board the Japanese-UK-US Hinode satellite, is now generating unprecedented observations enabling scientists to provide a new perspective on the 50-year old question of how solar wind is driven. The collaborative study, published in this month's issue of Astrophysical Journal, suggests that a process called slipping reconnection may drive these winds.

On Dec. 31, 2007, the sun awoke from the relatively quiescent period between Solar Cycles 23 and 24 to produce a solar flare that spewed high-energy neutrons into interplanetary space.

The Neutron Spectrometer flying aboard NASA's MESSENGER spacecraft recorded the event, giving scientists a first-ever, up-close look at neutron production from a solar flare. In fact, it was the first time scientists detected solar neutrons at less than 1 AU from the sun.

Images from the Ion and Neutral Camera on NASA's Cassini spacecraft suggest that the heliosphere, the region of the sun's influence, may not have the comet-like shape predicted by existing models.

In a paper published Oct. 15 in Science Express, researchers from the Johns Hopkins Applied Physics Laboratory present a new view of the heliosphere, and the forces that shape it.

The first all-sky maps developed by NASA's Interstellar Boundary Explorer (IBEX) spacecraft, the first mission to examine the global interactions occurring at the edge of the solar system, reveal surprising and intense interactions between our home in the galaxy and interstellar space.

"The IBEX results are truly remarkable, with emissions not resembling any of the current theories or models of this never-before-seen region," says Dr. David J. McComas, IBEX principal investigator and assistant vice president of the Space Science and Engineering Division at Southwest Research Institute. "We expected to see small, gradual spatial variations at the interstellar boundary, some ten billion miles away. However, IBEX is showing us a very narrow ribbon that is two to three times brighter than anything else in the sky."

Planning a trip to Mars? Take plenty of shielding. According to sensors on NASA's ACE (Advanced Composition Explorer) spacecraft, galactic cosmic rays have just hit a Space Age high.

"In 2009, cosmic ray intensities have increased 19% beyond anything we've seen in the past 50 years," says Richard Mewaldt of Caltech. "The increase is significant, and it could mean we need to re-think how much radiation shielding astronauts take with them on deep-space missions."

Every 11 years, the sun undergoes a furious upheaval. Dark sunspots burst forth from beneath the sun's surface. Explosions as powerful as a billion atomic bombs spark intense flares of high-energy radiation. Clouds of gas big enough to swallow planets break away and billow into space. It's a flamboyant display of stellar power.

So why can't we see any of it?

When NASA's Solar Dynamics Observatory (SDO) leaves Earth in November 2009 onboard an Atlas V rocket, the thunderous launch will trigger an avalanche. Mission planners are bracing themselves -- not for rocks or snow, but an avalanche of data.

"SDO will beam back 150 million bits of data per second, 24 hours a day, 7 days a week," says Dean Pesnell of the Goddard Space Flight Center in Greenbelt, Md. That's almost 50 times more science data than any other mission in NASA history. "It's like downloading 500,000 iTunes a day."

The Hinode satellite observing our sun captured images of the moon traversing the face of the sun during a solar eclipse this week.

On Wednesday, July 22, 2009, a total eclipse of the Sun was visible from within a narrow corridor that traverses half of Earth. The path of the Moon's umbral shadow began in India and crossed through Nepal, Bangladesh, Bhutan, Myanmar and China.

NASA is designing a mission to investigate one of the most fundamental and explosive physical processes in the universe - magnetic reconnection. Known as the Magnetospheric MultiScale (MMS) mission, it was approved for implementation on June 18, 2009 following a successful Preliminary Design Review in May 2009.

MMS consists of four identical satellites that will fly in a tetrahedron formation through Earth's magnetosphere to discover how magnetic reconnection works.