STEREO Detect Impossibly Fast Solar Eruption

The twin components of the NASA Solar TErrestrial RElations Observatory (STEREO) mission were recently able to detect one of the fastest and largest solar eruptions in recent history. On August 1, the Sun released a massive amount of matter and radiation, which sped away from the star at a whooping 2.2 million miles per hour. Despite this massive speed, the two spacecrafts were able to detect the event, and send their conclusions back to Earth, where researchers confirmed the discovery.

The large solar flare triggered a massive eruption called a coronal mass ejection (CME). This is one of the most dangerous things that can go on in the star, experts say. CME produce massive amounts of highly-energetic particles, which have the effect of a heavy bombardment on Earth's protective layer, the magnetosphere. The entire force of the ejection was unleashed on our planet on Tuesday, August 3, and the main result was a heavy intensification of the northern lights, the Aurora Borealis. We got off easy this time, solar physicists say, as larger CME can have devastating effects on our infrastructure.

Representatives of the American space agency said in a recent statement that “these kinds of eruptions are one of the first signs that the Sun is waking up and heading toward another solar maximum expected in the 2013 time frame.” The star functions in 11-year-old cycles, each of which contains a solar maximum and a minimum. These periods are named according to the amount of solar activity (sunspots, solar flares, CME) that takes place on the Sun's surface. Over the past two years, the star should have exited the minimum stage, and begin resuming its activity. But the minimum persisted, and it's only now that the Sun is beginning to show signs of recovery.

STEREO is in a unique position to conduct very accurate observations of the solar surface, given that its twin spacecrafts allow for it to look at the Sun in 3D. This allows solar physicists to get a depth-of-view in their studies, that is impossible with any other telescope. Not even the Solar Dynamic Observatory (SDO), the most advanced Sun-watching instrument, can produce 3D views of its targets. STEREO is capable of doing this because its components fly apart from each other, providing independent views of the same event from two vantage points, Space reports.

Analyzing the Sun's 'Magnetic Flux Ropes'

Image comment: The three images reveal gases trapped in the flux rope at different temperatures, from 1.5 million degrees Celsius in the image on the left through to 2.5 million degrees Celsius in the right hand image
Image credits: JAXA / ISAS / NASA / STFC

Coronal mass ejections (CME) are some of the most interesting and important phenomena going on on the surface of our Sun. As the years pass, astronomers and astrophysicists gain a deeper and deeper understanding of how these structures form and develop. This is of tremendous importance, as the CME have the potential to create secondary events that can fry power grids and satellites, radiate our planet, and jeopardize the lives of people working aboard the International Space Station (ISS). It would now appear that one of the keys to learning more of CME is analyzing magnetic flux ropes.

As some experts put it, almost nothing happens on the Sun without the presence of very strong magnetic fields. These structures can take on various shapes and sizes, and they can trigger solar tsunamis, sunspots, coronal mass emissions and so on. Given the perilous nature of some of these events, it stands to reason that experts want to learn more about how they form. That is why scientists at the University College London (UCL), in the United Kingdom, used the Hinode satellite to gain more data on how these extremely large magnetic fields form.

Magnetic flux ropes are a type of field that can be readily detected in the interplanetary space as CME approach our planet. This led experts to assume that they play an important role in stimulating the emissions. “Magnetic flux ropes have been observed in interplanetary space for many years now and they are widely invoked in theoretical descriptions of how CME are produced. We now need observations to confirm or reject the existence of flux ropes in the solar atmosphere before an eruption takes place to see whether our theories are correct,” explains UCL expert Dr Lucie Green, the lead researcher on the investigation.

“Flux ropes are thought to play a vital role in the evolution of the magnetic field of the Sun. However, the physics of flux ropes is applied across the Universe. For example, a solar physics model of flux rope ejection was recently used to explain the jets driven by the accretion disks around the supermassive black holes found in the center of galaxies,” the scientist adds. Details of the work conducted at UCL were presented today, April 12, at the RAS National Astronomy Meeting, in Glasgow, Scotland, AlphaGalileo reports.

Studying Coronal Mass Ejections in More Depth

Image comment: Image extracted from a CME eruption simulation, run at the University of California in Berkeley
Image credits: NRL / UCB

As our Sun is beginning to wake up from its prolonged period of solar minimum, researchers are again starting to take interest in the possible effects that this awakening may have on our planet. Earth itself is at no risk from these outbursts of hot, ionized gas from the star, but everything that operates with electricity is. Understanding the nature of coronal mass ejections (CME), and also that of the other phenomena associated with it, might help scientists devise better methods of taking care of Earth's satellites and power grids.

In addition, astrophysicists may learn more about the intricate phenomena going on inside the Sun, just under its surface. These mechanisms are the ones that promote the formation of these CME, which can have numerous “side-effects.” Some of these associated events include solar flares, eruptive prominences, coronal waves and post-eruptive arcades. Most of these phenomena in turn trigger the release of various forms of radiation, which are then spread throughout the solar system. Naturally, some of them also hit our planet, PhysOrg reports.

Fortunately, Earth is surrounded by a protective shield of sorts, a layer of the atmosphere called the magnetosphere. Its main role is to deflect incoming solar radiation, but the problem is that it does not protect our satellites, and the International Space Station (ISS). Given how much we rely on satellite communications, transmissions, and that six astronauts permanently inhabit the ISS, it stands to reason that losing our orbital capabilities would have far-reaching consequences. This is why predicting space weather has become so important over the past few years.

A new CME study is currently being carried out by a team of physicists at the US Naval Research Laboratory's (NRL) Space Science Division. The group wants to learn more about potential spacecraft anomalies and communication interruptions that events associated with CME might trigger. Establishing the composition of the ejections is one of the most important steps. Physicists say that this knowledge could help us determine how the events occur, and also how they propagate through interplanetary space.