A Weak Solar Flare Triggers a Gorgeous Spire of Plasma

The entire universe in blog form
May 4 2013 8:00 AM

Twisting Solar Eruption

Solar flare and prominence on May 3, 2013
The Sun had a bit of a hissy fit on May 3, 2013. See that blue dot above the prominence? That's about how big the Earth is. Click to enhelionate.

Photo by NASA/SDO.

Yesterday, May 3, 2013, a sunspot was pushed past its limit. The colossal energy stored in its magnetic field erupted, blasting out a relatively weak solar flare. But it was enough to trigger a magnificent, towering spire of plasma that reached the dizzying height of roughly 200,000 kilometers (120,000 miles) over the surface of the Sun before the material thinned out too much to see.

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!  

The image above is a combination of three different shots taken by NASA’s Solar Dynamics Observatory, each in the ultraviolet where such magnetic activity is easiest to see (I added the blue dot, which is roughly how big the Earth is, just to give you a sense of scale and to crush your brain). I also created a video of the event using Helioviewer.org; it shows about three hours of solar activity compressed into 19 seconds:



What you just saw is a pretty typical event for the Sun. Rising plasma (gas stripped of one or more electrons, giving it an electric field) inside the Sun has a magnetic field embedded in it. When it gets to the Sun’s surface, the magnetic field lines go up and down, piercing the surface. There can be quite a few of them, looping high over the surface, each storing more energy than all the nuclear weapons on Earth. The lines can get tangled, and if one of these loops crosses another, they can connect, like a short circuit. It releases its energy, which then twangs another loop, which snaps, and releases its energy…

solar flare on May 3, 2013
Kablam! The solar flare that triggered the prominence. Click to embiggen.

Photo by NASA/SDO

…and you get a sudden and explosive release of all that fury. That’s a solar flare (the flare itself from May 3 can be seen in the inset image). It perturbs everything around it, shaking the solar surface and the magnetic fields of other regions. In this case, it triggered an eruptive prominence, that huge tower of plasma. As the prominence rose, the magnetic field lines inside of it still hold sway, and you can see the top of it apparently twisting as it rises, flowing along those magnetic field lines (I’ve explained all this in more detail in an earlier post, too).

The Sun goes through a magnetic cycle, with its activity increasing from a minimum to a maximum over the course of about 5.5 years. It’s recently stalled a bit, with fewer sunspots and fewer flares than expected. It’s not at all clear if it’ll start to ramp up again, or if we’ve already passed the peak. The Sun is a bit like climate and weather; over long periods we can predict its climate, but over short periods its weather is a bit dicier to foretell. We’ll just have to wait and see what the future brings.

Tip o’ the welder’s goggles to Little SDO.



The Democrats’ War at Home

How can the president’s party defend itself from the president’s foreign policy blunders?

Congress’ Public Shaming of the Secret Service Was Political Grandstanding at Its Best

Michigan’s Tradition of Football “Toughness” Needs to Go—Starting With Coach Hoke

A Plentiful, Renewable Resource That America Keeps Overlooking

Animal manure.

Windows 8 Was So Bad That Microsoft Will Skip Straight to Windows 10


Cringing. Ducking. Mumbling.

How GOP candidates react whenever someone brings up reproductive rights or gay marriage.

Building a Better Workplace

You Deserve a Pre-cation

The smartest job perk you’ve never heard of.

Hasbro Is Cracking Down on Scrabble Players Who Turn Its Official Word List Into Popular Apps

Florida State’s New President Is Underqualified and Mistrusted. He Just Might Save the University.

  News & Politics
Sept. 30 2014 9:33 PM Political Theater With a Purpose Darrell Issa’s public shaming of the head of the Secret Service was congressional grandstanding at its best.
Sept. 30 2014 7:02 PM At Long Last, eBay Sets PayPal Free
Sept. 30 2014 7:35 PM Who Owns Scrabble’s Word List? Hasbro says the list of playable words belongs to the company. Players beg to differ.
  Double X
The XX Factor
Sept. 30 2014 12:34 PM Parents, Get Your Teenage Daughters the IUD
  Slate Plus
Behind the Scenes
Sept. 30 2014 3:21 PM Meet Jordan Weissmann Five questions with Slate’s senior business and economics correspondent.
Brow Beat
Sept. 30 2014 8:54 PM Bette Davis Talks Gender Roles in a Delightful, Animated Interview From 1963
Future Tense
Sept. 30 2014 7:00 PM There’s Going to Be a Live-Action Tetris Movie for Some Reason
  Health & Science
Medical Examiner
Sept. 30 2014 11:51 PM Should You Freeze Your Eggs? An egg freezing party is not a great place to find answers to this or other questions.
Sports Nut
Sept. 30 2014 5:54 PM Goodbye, Tough Guy It’s time for Michigan to fire its toughness-obsessed coach, Brady Hoke.