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


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.


Sports Nut

Grandmaster Clash

One of the most amazing feats in chess history just happened, and no one noticed.

The Extraordinary Amicus Brief That Attempts to Explain the Wu-Tang Clan to the Supreme Court Justices

Amazon Is Officially a Gadget Company. Here Are Its Six New Devices.

Do the Celebrities Whose Nude Photos Were Stolen Have a Case Against Apple?

The NFL Explains How It Sees “the Role of the Female”

Future Tense

Amazon Is Now a Gadget Company


How to Order Chinese Food

First, stop thinking of it as “Chinese food.”

Scotland Is Inspiring Secessionists Across America

The Country Where Women Aren’t Allowed to Work Once They’re 36 Weeks’ Pregnant

The XX Factor
Sept. 18 2014 11:40 AM The Country Where Women Aren’t Allowed to Work Once They’re 36 Weeks’ Pregnant
Sept. 17 2014 5:10 PM The Most Awkward Scenario in Which a Man Can Hold a Door for a Woman
  News & Politics
Sept. 18 2014 3:19 PM In Defense of Congress Leaving Town Without a New War Vote
Business Insider
Sept. 18 2014 3:31 PM What Europe Would Look Like If All the Separatist Movements Got Their Way
Sept. 18 2014 3:24 PM Symantec Removes Its “Sexual Orientation” Filter
  Double X
The XX Factor
Sept. 18 2014 3:30 PM How Crisis Pregnancy Centers Trick Women
  Slate Plus
Behind the Scenes
Sept. 18 2014 1:23 PM “It’s Not Every Day That You Can Beat the World Champion” An exclusive interview with chess grandmaster Fabiano Caruana.
Sept. 18 2014 4:00 PM When The Cosby Show Got “Very Special” Why were The Cosby Show’s Very Special Episodes so much better than every other ’80s sitcom’s?
Future Tense
Sept. 18 2014 2:39 PM Here's How to Keep Apple From Sharing Your iPhone Data With the Police
  Health & Science
Sept. 18 2014 3:35 PM Do People Still Die of Rabies? And how do you know if an animal is rabid?
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.