Since being launched from Cape Canaveral, Florida, on February 11, 2010, NASA’s Solar Dynamics Observatory (SDO) has captured stunning images and video of the sun in action.
SDO is documenting solar events such as solar prominences, solar flares, coronal mass ejections and high-speed solar wind. A solar prominence is an enormous eruption of plasma from the sun’s surface. Solar prominences often appear as loops—some so large that several Earth-sized planets could fit inside. A solar flare is a blast of radiation associated with sunspots. A coronal mass ejection (CME) is a sudden release of gas bubbles and magnetic fields from the sun’s atmosphere. Solar wind is the constant ejection of electrically charged particles from the sun.
These features can wreak havoc on technology on Earth in a phenomenon known as space weather.
“Space weather, in a nutshell, is the conditions in the space environment that we are interested in because they have impacts on the health and safety of equipment and humans in space and on the ground,” says Michael Hesse, chief of the Space Weather Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
According to Phil Chamberlin, a NASA research astrophysicist and one of the deputy project scientists for SDO, space weather can be quite a nuisance here on Earth. “It mostly influences technology,” he says. “It could affect our GPS [global positioning systems] and how accurate it is. It could actually render it useless. That’s something a lot of people are becoming very dependent upon.”
On aircrafts flying above Earth’s polar regions, crew members rely on high-frequency radio for communication. Some space weather events have created radio blackouts for several days in polar areas.
Hesse says that in extreme cases, space weather can lead to a disruption in the power grid. In 1989, space weather caused 6 million people in Quebec, Canada, to lose electrical power for more than nine hours.
Space weather could have been a grave danger for astronauts who went into space as part of NASA’s Apollo missions between 1968 and 1972. “Historically, we have been very lucky, because we didn’t know these effects during the Apollo era,” Hesse says. “In the worst case scenario, astronauts could have gotten seriously injured on these trips if one of those major events had happened.”
Living with a Star
Chamberlin says learning more about space weather is one of the observatory’s primary missions.
“It [SDO] is part of NASA’s ‘Living with a Star’ program,” he says. “So it’s not only to understand the sun, but it’s living with a star and understanding how the sun influences us on Earth.”
Instead of having a hard drive to store images and video of the sun, SDO is constantly streaming data—equivalent to half a million songs from iTunes every day—to a ground station in Las Cruces, New Mexico.
“We get pretty much an image every second,” Chamberlin says, adding that the picture quality “is 10 times better than high-definition television.”
SDO gives NASA’s scientists massive amounts of new information about the sun.
“For the first time, we have the full sun, all the time, every second,” Chamberlin says. “There are no data gaps in this. We’re seeing that very often, one flare will trigger another flare all the way on the other side of the sun. We don’t know what actually is the root cause of this and how these things are connected, but we are trying to get the statistics to know that they are.”
The data gleaned from SDO are more than just pretty pictures of solar events. Hesse is hoping the data can help scientists at the Space Weather Laboratory better forecast space weather.
“The benefit that we get from this is that we can determine with really good accuracy where on the surface of the sun the eruption occurred,” he says. “If you want to find out where it is going in space, to know where it started out from is extremely helpful.”
Hesse says space weather forecasts are made using data from SDO and the Solar Terrestrial Relations Observatory (STEREO). STEREO is a NASA program that uses two space-based observatories to gather information about the sun.
“We are looking every day at the STEREO spacecraft and at SDO to basically know are there any active regions or regions of strong magnetic fields where energy is being stored that can lead to eruptions,” he says. “You develop all the time a feeling for what an active region looks like that can lead to an eruption. . . . We are still really at the scientific forefront here trying to understand how an eruption actually happens and what makes it happen and when is it going to happen.”
