Twin NASA Satellites See Giagntic Solar Eruption from Two Angles

The entire universe in blog form
Nov. 25 2012 8:00 AM

Angling in on a Massive Solar Eruption

Our Sun is a feisty beast.

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

It’s a roiling cauldron of gas, so hot that electrons in the gas have been stripped away, creating what’s called a plasma. Currents of rising and twisting plasma underneath the Sun’s surface create intense and convoluted magnetic fields, which in turn affect the shape and behavior of the gas. Piercing the surface, these magnetic fields create gigantic loops along which the plasma flows, like beads along the wires of an abacus. Vast energies are stored in these loops, and sometimes they explode. Violently. Very, very violently.

Two images from space of a massive solar eruption
Two views of a huge solar eruption from NASA's twin STEREO spacecraft. Click to ensolarnate.

Image credit: NASA/STEREO

Advertisement

That image shows what’s called a prominence, one of these towering arcs of plasma. You can see it clearly in the bottom picture, but where is it in the top one?

Oh, it’s there, but you need a little perspective to see it. These two images were taken by NASA’s STEREO (for Solar TErrestrial RElations Observatory) satellites; twin spacecraft that view the Sun from two widely different angles. One was launched in a way that sent it ahead of the Earth in its orbit (called STEREO A for “ahead”) and the other launched to lag behind (STEREO B, for “behind”).

On Oct. 14, 2012, the spacecraft took the two pictures above. I’ve labeled them to show which is the view from which spacecraft. STEREO A saw the loop from the side, arcing high above the Sun’s surface—about 500,000 kilometers (300,000 miles), judging from the picture. That’s greater than the distance from the Earth to the Moon!

STEREO B, on the other hand, was almost directly above that eruption, so it sees it edge-on, if you will, looking straight down on it. If you take a moment you can match up some features on the Sun in the two pictures; for example, the white twisted spot to the lower left of the eruption near the Sun’s left edge in the upper image can be seen in the lower one as well.

Note that in the top image it's labeled as a filament, but in the bottom the eruption is labeled as a prominence. Those mean the same thing! Kinda; it depends on your viewpoint. When seen against space, like in the lower image, it’s called a prominence. But when seen against the face of the Sun, like in the upper image, it’s called a filament. That’s a holdover from when we didn’t really understand the Sun very well; the same feature looks very different depending on how you see it. That should be clear from these two images! So the same event has two names, and we still use both.

No matter what you call it, it’s a spine-chilling event. What you’re seeing here is an eruption that launched billions of tons of gas into space at high speed; an explosion releasing the energy equivalent to at least thousands of times the combined nuclear arsenals of every country on Earth! The Sun doesn’t do anything small.

And hopefully, that will give you a little perspective on our nearest star.

TODAY IN SLATE

Politics

Meet the New Bosses

How the Republicans would run the Senate.

The Government Is Giving Millions of Dollars in Electric-Car Subsidies to the Wrong Drivers

Scotland Is Just the Beginning. Expect More Political Earthquakes in Europe.

Cheez-Its. Ritz. Triscuits.

Why all cracker names sound alike.

Friends Was the Last Purely Pleasurable Sitcom

The Eye

This Whimsical Driverless Car Imagines Transportation in 2059

Medical Examiner

Did America Get Fat by Drinking Diet Soda?  

A high-profile study points the finger at artificial sweeteners.

The Afghan Town With a Legitimately Good Tourism Pitch

A Futurama Writer on How the Vietnam War Shaped the Series

  News & Politics
Photography
Sept. 21 2014 11:34 PM People’s Climate March in Photos Hundreds of thousands of marchers took to the streets of NYC in the largest climate rally in history.
  Business
Business Insider
Sept. 20 2014 6:30 AM The Man Making Bill Gates Richer
  Life
Quora
Sept. 22 2014 8:07 AM Why Haven’t the Philadelphia Eagles Ever Won a Super Bowl?
  Double X
The XX Factor
Sept. 19 2014 4:58 PM Steubenville Gets the Lifetime Treatment (And a Cheerleader Erupts Into Flames)
  Slate Plus
Science
Sept. 22 2014 8:08 AM Slate Voice: “Why Is So Much Honey Clover Honey?” Mike Vuolo shares the story of your honey.
  Arts
Television
Sept. 21 2014 9:00 PM Attractive People Being Funny While Doing Amusing and Sometimes Romantic Things Don’t dismiss it. Friends was a truly great show.
  Technology
Future Tense
Sept. 22 2014 7:47 AM Predicting the Future for the U.S. Government The strange but satisfying work of creating the National Intelligence Council’s Global Trends report.
  Health & Science
Bad Astronomy
Sept. 22 2014 5:30 AM MAVEN Arrives at Mars
  Sports
Sports Nut
Sept. 18 2014 11:42 AM Grandmaster Clash One of the most amazing feats in chess history just happened, and no one noticed.