A spacecraft far from Earth turned and watched a solar storm engulfed the planet for the first time, and NASA released a movie on the act, which solar physicists say could lead to important advances in space weather forecasting.
The movie sent chills down my spine, said Craig DeForest of the Southwest Researcher Institute in Boulder, Colo. in a statement. It shows a CME swelling into an enormous wall of plasma and then washing over the tiny blue speck of Earth where we live. I felt very small.
According to NASA, CMEs are billion-ton clouds of solar plasma launched by the same explosions that spark solar flares. And, whenever they sweep past our planet, they can cause auroras, radiation storms, and in extreme cases power outages.
Tracking these clouds and predicting their arrival is an important part of space weather forecasting.
The movies pinpoint both the arrival time of the CME and its mass, and from the brightness of the cloud, researchers can precisely calculate the gas density.
We have seen CMEs before, but never quite like this, said Lika Guhathakurta, program scientist for the STEREO mission at NASA headquarters, also in a statement. STEREO-A has given us a new view of solar storms.
STEREO-A is one of two spacecrafts launched in 2006 for the purpose of observing solar activity from widely-spaced locations. When the storm occurred, STEREO-A was more than 65 million miles from Earth, giving it the big picture view other spacecraft in Earth's orbit lack, NASA said.
The space agency added that when CMEs first leave the sun, they are bright and easy to see. But that visibility is quickly reduced as the clouds expand into the void. Then, by the time a typical CME crosses the orbit of Venus, it is a billion times fainter than the surface of the full Moon, and more than a thousand times fainter than the Milky Way, NASA said, adding that CMEs that reach Earth are almost as gossamer as vacuum itself and correspondingly transparent.
Pulling these faint clouds out of the confusion of starlight and interplanetary dust has been an enormous challenge, DeForest says.
And, it took almost three years for his team to learn how to do it.
Thursday's footage of the storm was recorded in December 2008, and they have been working on it ever since.
Now, with a perfected technique, it can be regularly applied without such a long delay, NASA said.
The ability to track a cloud continuously from the Sun to Earth is a big improvement, Alysha Reinard of NOAA's Space Weather Prediction Center said in a statement. In the past, our very best predictions of CME arrival times had uncertainties of plus or minus four hours. The kind of movies we've seen today could significantly reduce the error bars.
Watch NASA's videos below.
STEREO Tracks Solar Storms From Sun To Earth: NASA's STEREO spacecraft and new data processing techniques have succeeded in tracking space weather events from their origin in the sun's corona to impact with the Earth, resolving a 40-year mystery about the structure of the structures that cause space weather: how the structures that impact the Earth relate to the corresponding structures in the solar corona.
STEREO, ACE and Wind Witness Dec. 2008 CME: This video shows images taken by the various instruments on board the STEREO Ahead spacecraft of the December 2008 coronal mass ejection's path from the Sun to Earth. Closer to Earth is a dial showing the solar wind density changes at Lagrangian point L1 where the ACE and Wind spacecraft recorded the event.
December 2008 CME as Viewed by Spacecraft: Newly reprocessed images from NASA's STEREO-A spacecraft, allow scientists to trace the anatomy of the December 2008 CME as it moves and changes on its journey from the Sun to the Earth, identify the origin and structure of the material that impacted Earth, and connect the image data directly with measurements at Earth at the time of impact.
2008 CME's Path Though Inner Solar System: Based on actual data, this animated graphic shows the path through the inner solar system of a coronal mass ejection (CME) that occurred in December 2008. The twin STEREO spacecrafts are also present as observers of the event.