Predicting Space Weather Starts with the Sun
Posted: June 12, 2008 at 1:00 am, Last Updated: November 30, -0001 at 12:00 am
The sun spews an enormous magnetized jet of gas. The jets emit radiation and can affect satellites in space. (Roll over image to display video control.)
Scientific theories have discussed how a butterfly in Asia flapping its wings can lead to a tornado on the other side of the world. So it’s no surprise that Mason researchers in astrophysics are examining a hot eruption on the surface of the sun that causes GPS systems on Earth to go haywire.
Eruptions on the surface of the sun, some as long as five times the size of Earth, are highly magnetized and emit radiation, all of which can damage man-made satellites.
Recently, research assistant professors Spiros Patsourakos and Etienne Pariat discovered some important evidence about the formation and shape of these jets. Using two STEREO spacecrafts from NASA, the researchers were able to get two different perspectives on these jets and construct the first 3-D image of one.
They were able to confirm what has been theorized for several years now — that the emissions are a consequence of the twisting of the sun’s magnetic field as it rotates on its axis. They published a paper on the subject in The Astrophysical Journal, Vol. 680, 2008.
The findings were payback for the two scientists, who have been looking at these solar events for years, hoping to understand how they form, what they look like and, eventually, how to predict them.
“The twist is what’s important,” says Pariat, who believes that the magnetic fields build up in tension as they twist, and then snap like a rubber band, causing the jet gas to erupt.
Jet propulsions, according to Pariat, have an Eiffel Tower kind of shape and happen fairly regularly — about six to 10 per hour — but only last about 10 minutes. To study one, researchers have to be able to take many images quickly.
“Before the two spacecraft, it was as though we were looking with only one eye and had no real understanding of the image,” he says. “Now with two spacecraft, we are actually seeing with two eyes and getting a full perspective. We were not expecting the structure to appear so quickly. We were very happy with the result.”
The researchers are also looking at the wider implications of their research. “Given the relative simplicity of jets, understanding them could prove to be the Rosetta Stone for understanding the larger-scale eruptions,” says Patsourakos.
The biggest of these events are coronal mass ejections, which emit radiation that can extend all the way to Earth. The scientists would like to be able to eventually predict this “space weather” to help understand and minimize the effects these ejections have on life on Earth.
“Solar eruptions could have been happening for billions of years,” says Patsourakos, however, they have not had much effect on Earth life because our magnetic field helps to protect us. Yet our modern society relies more and more on satellite technology for telecommunications such as cell phones and GPS systems — and the satellites we send into space go beyond the protection of the magnetic field, thus leaving them vulnerable to the high energy from the sun.
Their work will also help to protect astronauts working in space and will be needed for future space trips and exploration of other planets such as Mars.
Two eyes are better than one: STEREO views (upper left and right) of a jet that erupted from the north pole of the sun in June 2007 show a twisted structure (orange), an indication that tangled magnetic fields propelled the jet. The middle image shows the jet as seen by the single perspective of the SOHO spacecraft.