The Anatomy of a Solar Explosion in 3-D
Written by Nancy Atkinson
Wouldn't it be great if solar physicists could predict sun storms just like meteorologist predict hurricanes? Well, now perhaps they can. NASA’s twin STEREO observatories have made the first 3-D measurements of solar explosions, known as coronal mass ejections (CMEs), allowing scientists to see their size and shape, and image them as they travel approximately 93 million miles from the sun to Earth. With STEREO, scientists can now capture images of solar storms and make real-time measurements of their magnetic fields, much the same way that satellites allow forecasters to see the development of a hurricane. Eruptions from the sun’s outer atmosphere, or corona, can wreak havoc on satellites (and astronauts) in orbit or induce large currents in power grids on Earth, which can cause power disruptions or black outs.
"We can now see a CME from the time it leaves the solar surface until it reaches Earth, and we can reconstruct the event in 3D directly from the images," said Angelos Vourlidas, a solar physicist at the Naval Research Laboratory, Washington, and project scientist for the Sun Earth Connection Coronal and Heliospheric Investigation aboard STEREO. In the video above, see some of the 3-D imagery, and hear Vourlidas talk about about the new findings.
STEREO-A viewing a coronal mass ejection leaving the sun between December 12-13, 2008. Credit: NASA
CMEs spew billions of tons of plasma into space at thousands of miles per hour and carry some of the sun’s magnetic field with it. These solar storm clouds create a shock wave and a large, moving disturbance in the solar system. The shock can accelerate some of the particles in space to high energies, a form of "solar cosmic rays" that can be hazardous to spacecraft and astronauts. The CME material, which arrives days later, can disrupt Earth’s magnetic field, or magnetosphere, and upper atmosphere.
STEREO consists of two nearly identical observatories that make simultaneous observations of CMEs from two different vantage points. One observatory 'leads' Earth in its orbit around the sun, while the other observatory 'trails' the planet. STEREO’s two vantage points provide a unique view of the anatomy of a solar storm as it evolves and travels toward Earth. Once the CME arrives at the orbit of Earth, sensors on the satellites take in situ measurements of the solar storm cloud, providing a "ground truth" between what was seen at a distance and what is real inside the CME.
The combination is providing solar physicists with the most complete understanding to date of the inner workings of these storms. It also represents a big step toward predicting when and how the impact will be felt at Earth. The separation angle between the satellites affords researchers to track a CME in three dimensions, something they have done several times in the past few years as they have learned to use this new space weather tool.
Visualization of a coronal mass ejection event on December 12-13, 2008 as seen simultaneously by the two STEREO spacecraft. The images on the right were taken by STEREO-A, while the images on the left were taken by STEREO-B. The images were taken by the COR2 telescopes on STEREO’s SECCHI instrument suite. Credit: NASA
"The in situ measurements from STEREO and other near-Earth spacecraft link the physical properties of the escaping CME to the remote images," said Antoinette "Toni" Galvin, a solar physicist at the University of New Hampshire, and the principal investigator on STEREO’s Plasma and Suprathermal Ion Composition (PLASTIC) instrument. "This helps us to understand how the internal structure of the CME was formed and to better predict its impact on Earth."
Until now, CMEs could be imaged near the sun but the next measurements had to wait until the CME cloud arrived at Earth three to seven days later. STEREO’s real-time images and measurements give scientists a slew of information—speed, direction, and velocity—of a CME days sooner than with previous methods. As a result, more time is available for power companies and satellite operators to prepare for potentially damaging solar storms.
Much like a hurricane’s destructive force depends on its direction, size, and speed, the seriousness of a CME’s effects depends on its size and speed, as well as whether it makes a direct or oblique hit across Earth’s orbit.
CMEs disturb the space dominated by Earth's magnetic field. Disruptions to the magnetosphere can trigger the brightly colored, dancing lights known as auroras, or Northern and Southern Lights. While these displays are harmless, they indicate that Earth’s upper atmosphere and ionosphere are in turmoil.
Sun storms can interfere with communications between ground stations and satellites, airplane pilots, and astronauts. Radio noise from a storm can also disrupt cell phone service. Disturbances in the ionosphere caused by CMEs can distort the accuracy of Global Positioning System (GPS) navigation and, in extreme cases, induce stray electrical currents in long cables and power transformers on the ground.
The twin STEREO spacecraft were launched October 25, 2006, into Earth’s orbit around the sun.
Filed under: Solar Astronomy
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April 14th, 2009 at 7:28 pm
As usual, people tend to get mislead with things that are "seemingly" new… Thus, I thought I should point out that people (myself included) at the Center for Astrophysics and Space Sciences (CASS) at the University of California, San Diego (UCSD) have been doing this for years already! This has been in the form of C.A.T. reconstructions of the complete inner heliosphere showing its gross structure as well as the 3D shape, size, and mass calculations of CMEs (solar storms) using both interplanetary scintillation (IPS) and the Solar Mass Ejection Imager (SMEI) all-sky white-light-imaging instrument (which looks at nearly all of the sky all of the time – unlike the STEREO HI instruments which only image a small part of the sky). So, this stuff here isn't exactly new, it's just being done with a different set of instruments…
April 14th, 2009 at 7:31 pm
Seems my comment can't be posted…
April 14th, 2009 at 7:34 pm
OK, oops! My apologies… The response I was getting was saying my comment was "undefined" and thus I kept trying to type it out… Sorry for the same comment multiple times…
April 14th, 2009 at 8:27 pm
Whenever you get an undefined response to a posting, try refreshing the page. You will then see your post. That has worked every time for me.
April 14th, 2009 at 8:36 pm
Yeah… I gathered that… Now… Oops! Thanks though…
April 14th, 2009 at 9:00 pm
"So, this stuff here isn’t exactly new, it’s just being done with a different set of instruments…"
Perhaps not new per se, but surely these different techniques will be complementary, and throw some interesting light on one another…
I'm loving the armada of craft studying the Sun and it's environment at the moment. Interesting results coming through all the time.
April 15th, 2009 at 10:25 am
I agree Astrofiend , the more different techniques point to the same resuilt, the more likely the result is correct.
The best tests in any theory is cross-checking with completely different techniques and technologies.
April 16th, 2009 at 5:35 am
re: Olaf
To borrow a quote from ya, "The best tests in any theory is cross-checking with completely different techniques and technologies."
First thing that came to my mind was: tell that to the rest of the scientific community! This is like the foundation of science, at least it was before a few keystrokes replaced the shorthand teachers had to plead for in grade school days (aka "Show you work!" in math class).
How many proofs do you think astronomers run on these gregarious equations, just to double check their work? None, not with our infalliable CPUs. I'd wager they couldn't even handwrite-solve half the equations they cite as 'evidence' for particular theories.
News like this excites me…being an Electric Universe proponent myself, it's becoming clear that as these recent and upcoming analysis (with our more powerful than ever optical equipment) will FINALLY make it painfully clear to any/all astrophysicists that good ole Electromagnetism and the like need seriouslly readdressed.
Every other new article of late seems to be pointing in such a direction, hopefully in due time it will get to a point where it makes the brash and antagonizing OilIsMastery type attacks moot. Meanwhile, I'll gladly sit back and lurk on more space/science blogs than should me humanly possible, rarely interjecting save for any slanderous/libel attacks on the EU.
The answer is easy. Ya'll are gonna have get off your high horses eventually and learn to accept things for what they are, but more importantly, we EU-ians need to quit being so holier-than-thou / smug about such things (Especially before theyre accepted mainstream). We need to come together, and figure out this darn Sun ASAP, if we don't get a handle on it (and thus reap the rewards of all that will come with this understanding) it's gonna obliterate a majority of us, rendering all of our postering and difference MOOT. Hands Across America people, lets go!
My other feeling towards the dividing forces/sides is that in a way, the failure of Relativity to explain more new observations than it understands actually benefitted us all in the end. Since we felt we needed to look deeper and deeper and farther and broader to find the evidence to confirm the Standard Model, we have now/continue to amass an absolutely INCREDIBLE amount of data/imagery on the Universe, and in the end we'll be better off for it.
Thanks for your time
April 17th, 2009 at 12:53 am
I just wish people wouldn't claim completely "new" things when they're not, it's just so frustrating, especially when people write articles like this without going to the additional research and at least acknowledge previous works which are of at least equal standing…
April 18th, 2009 at 7:55 am
@ Olaf: After reading Matt's post on your earlier comments, this is why I worry about some visitors and neophytes who visit UT and read and follow some of these pseudo-sciences & decide they 'like' this theory over the standard model for whatever reason. We discussed this with ND over at the MACSJ0717 galaxy cluster postings. Anyway, Matt seems to be a long-time EU proponent (could that be considered slander?). @ Mario: I hear what you're saying. I've read a few publicity releases from Hubble, Chandra, and Spitzer that make it seem their new observations have 'discovered' some new phenomenon where in truth it only confirms earlier observations. A few people at this site have posted similar concerns. When I read the actual paper on the new observations, rarely do the authors claim to have discovered any unknown or unforseen phenomenon.