“Something New Under the Sun”
by Rob Irion
Smithsonian, April 2011
Staring at the Sun
The hottest IMAX movie around is now playing at NASA and in science labs in northern California. It’s a 24/7 high-definition view of our sun, and it’s showing how the star that gives us life can also wreak havoc with our way of life.
The footage comes courtesy of the Solar Dynamics Observatory, an $850 million satellite launched in February. The observatory stares at the sun from a spot 22,500 miles high. It takes detailed images every 10 seconds, exposing the churnings of the sun’s interior and its flares of extreme ultraviolet light. Streams of data reveal the genesis of sunspots and eruptions that can cripple satellites in orbit and power grids on the ground.
In its angrier moods, the sun hurls giant storms of magnetized gas into space. The ones aimed at Earth crash into our planet’s protective magnetic field in a couple of days. The effects range from pretty (aurora borealis) to potent (communications blackouts). The worst flares could kill astronauts — a real concern as we ponder sending explorers to asteroids or beyond.
Our data networks are now so pervasive, and so reliant on swarms of satellites, that a major solar outburst could bring them down. A recent federal report concluded that a solar storm the size of the biggest one in the last century could cause 20 times more financial damage than Hurricane Katrina.
How the sun sparks these storms is a longstanding mystery. Solving it is the observatory’s core mission for the next five years. NASA purposefully launched it now, during one of the sun’s quiet phases, so that scientists can watch as sunspots build up toward the next peak of violent outbursts in 2013 or 2014. Already, they’ve seen that even a minor flare on one side of the sun can spark a major belch of gas on the other side. That unexpected connection had eluded the fuzzier eyes of previous solar telescopes.
In a 3,000-word feature for Smithsonian, I’d like to report on what scientists are learning about the sun by visiting two of the teams that created the Solar Dynamics Observatory. One, based at Stanford University and led by Philip Scherrer, made an instrument that acts like a seismometer by detecting the sun’s constant inward and outward pulses of gas. By analyzing these vibrations, the team maps the magnetic currents inside the sun, more than 100,000 miles deep. That’s where tangled magnetic fields first give rise to sunspots. Tracing the origins of these disturbances will lead to better “space weather” forecasts by NASA — far enough in advance that power companies and satellite operators could take precautions.
The second team, based at Lockheed Martin in Palo Alto and led by Alan Title, built the camera system that takes sharp pictures of the sun’s million-degree atmosphere across its entire face. The cameras reveal details as small as 450 miles wide in the zone where the flares and storms erupt into space. The images show how much energy these storms pack, and how much of a threat they might pose to Earth. By tracking how sunspots change, the cameras will provide deep insights into the physics of the sun’s atmosphere
— where magnetic fields twist up like tortured skeins of rubber bands that can snap at any time.
Both Scherrer and Title have studied the sun for decades, and they’ll both have rich tales to tell. I interviewed each scientist in 1999 for a feature in New Scientist; the new data blows away that old research. At Lockheed, I’ll report from a video room that displays live feeds from the satellite on a wall full of screens. The researchers use this facility to play data in time-lapse fashion, turning the formerly static sun into a writhing ball of stormy gas. At Stanford, I’ll see the magnetic maps made by the team, which scientists use to chart the sun’s internal “magnetic dynamo” that drives all of its activity.
“We now have all of the sun, all of the time,” says Scherrer, whose group is learning how to work with the satellite’s stream of 150 megabytes of data every second. “This is really a golden age for solar research,” adds his colleague, physicist Todd Hoeksma. “We have the best eyes we’ve ever had.”
Finally, the observatory should help researchers grasp the sun’s role in climate change on Earth. Global-warming naysayers have argued that even tiny changes in the sun’s output of energy can swamp any effects that humans have on the planet’s temperature. The satellite will measure those variations of solar energy more finely than ever.
The feature offers rich options for art — notably with the extraordinary images from the satellite itself. For a sampling, see the mission site:
Lockheed Martin, where engineers built two of the observatory’s three main instruments, also will have a wealth of hardware photos.
Solar physics is a tough nut to crack, but the sun is warm, ever-present, and inviting. Readers will welcome this new look at our neighbor in space. I’d enjoy reporting and writing it for you by early September, in time for the special astro issue.