By Jonathan Amos
Science correspondent, BBC News


Nasa's Solar Dynamics Observatory has provided an astonishing new vista on our convulsing star.

The first public release of images from the satellite record huge explosions and great looping prominences of gas.

The observatory's super-fine resolution is expected to help scientists get a better understanding of what drives solar activity.

Launched in February on an Atlas rocket from Cape Canaveral, SDO is expected to operate for at least five years.

Researchers hope in this time they will go a long way towards their eventual goal of being able to forecast the Sun's behaviour in much the same way as meteorologists are able to forecast the weather on our planet.

Solar activity has a profound influence at Earth. Huge eruptions of charged particles and the emission of intense radiation can disrupt satellite, communication and power systems, and pose a serious health risk to astronauts.

Scientists working on SDO say they are thrilled with the quality of the data received so far.

"When we see these fantastic images, even hard-core solar physicists like myself are struck with awe, literally," said Lika Guhathakurta, the SDO programme scientist at Nasa Headquarters.

SDO is equipped with three instruments to investigate the physics at work inside, on the surface and in the atmosphere of the Sun.

The probe views the entire Sun with a resolution 10 times better than the average high-definition television camera. This allows it to pick out features on the surface and in the atmosphere that are as small as 350km across.

The pictures are also acquired at a rapid rate, every few seconds.

In addition, the different wavelengths in which the instruments operate mean scientists can study the Sun's atmosphere layer by layer.

A key quest will be to probe the inner workings of the solar dynamo, the deep network of plasma currents that generates the Sun's tangled and sometimes explosive magnetic field.

It is the dynamo that ultimately lies behind all forms of solar activity, from the solar flares that explode in the Sun's atmosphere to the relatively cool patches, or sunspots, that pock the solar disc and wander across its surface for days or even weeks.

"The SDO images are stunning and the level of detail they reveal will undoubtedly lead to a new branch of research into how the fine-scale solar magnetic fields form and evolve, leading to a much, much better understanding of how solar activity develops," said co-investigator Richard Harrison from the UK's Rutherford Appleton Laboratory (RAL).

"It's like looking at the details of our star through a microscope," he told BBC News.


SDO's three remote-sensing instruments are:

Helioseismic and Magnetic Imager (HMI) : will study the motions and magnetic fields at the Sun's surface, or photosphere, to determine what is happening inside the star. It will try to decipher the physics of the solar dynamo - the very source of the Sun's activity. The dynamo regulates all forms of solar activity from the lightning-fast eruptions of solar flares to the slow decadal undulations of the sunspot cycle.

Atmospheric Imaging Assembly (AIA) : is a suite of four telescopes that will image the corona, the outer layer of the Sun's atmosphere. The AIA filters cover 10 different wavelength bands, or colours, from the extreme ultraviolet to the visible. It will see details as small as 725km across. These images will be acquired every 10 seconds. Previous observatories have taken pictures at best every few minutes.

Extreme Ultraviolet Variability Experiment (EVE) : will measure the Sun's energy output in extreme-ultraviolet (E-UV) wavelengths (this is called irradiance) with unprecedented precision. The Sun is at its most variable in the E-UV. E-UV rays can break apart atoms and molecules in the Earth's upper-atmosphere, creating a layer of ions that can severely disturb radio signals.

The UK has a prominent role in the mission through the Rutherford Appleton Laboratory in Didcot; the e2v company in Chelmsford which supplied CCD camera detectors; the Mullard Space Science Laboratory in London; the University of Warwick; the University of Sheffield; and the University of Central Lancashire (UCLan) in Preston.

UCLan handles the SDO data coming into the UK. With the mission producing some 1.5 tera-bytes per day, it requires a dedicated gateway for scientists to exploit.


http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/8635207.stm

And here is the link to their website:

http://sdo.gsfc.nasa.gov/

Direct link to the movies:

http://sdo.gsfc.nasa.gov/firstlight/

SDO Observes Massive Eruption, Scorching Rain

April 27, 2010: Just last week, scientists working with NASA's new Solar Dynamics Observatory (SDO) released the most astonishing movies of the sun anyone had ever seen. Now, they're doing it again.

"SDO has just observed a massive eruption on the sun—one of the biggest in years," says Lika Guhathakurta of NASA headquarters in Washington DC. "The footage is not only dramatic, but also could solve a longstanding mystery of solar physics."

Karel Schrijver of Lockheed Martin's Solar and Astrophysics Lab is leading the analysis. "We can see a billion tons of magnetized plasma blasting into space while debris from the explosion falls back onto the sun surface. These may be our best data yet."



The movie, recorded on April 19th, spans four hours of actual time and more than 100,000 km of linear space. "It's huge," says Schrijver. Indeed, the entire planet Earth could fit between the plasma streamers with room to spare.
Coronal Rain (200 pixels)
Coronal rain. Encircled are two plasma streamers, one hitting the sun's surface and another incoming behind it.

Astronomers have seen eruptions like this before, but rarely so large and never in such fluid detail. As science team member Alan Title of Lockheed Martin pointed out at last week's press conference, "no other telescope comes close to the combined spatial, temporal and spectral resolution of SDO."

con.

http://science.nasa.gov/science-news/sc ... lasmarain/