SDO opens its eyes and sees our star like never before

By Phil Plait | April 30, 2010 7:01 am

Last week, NASA presented the first images and videos from its latest and greatest eye on the Sun: the Solar Dynamics Observatory.

SDO has been in the works for a long, long time, and I’ve been anxiously awaiting data from it for years… so of course I was away from my computer when the images were released. Still, it was worth a few extra days to see something as back-of-the-neck-hair-raising as this:


Holy Haleakala! Click to emprominate.

As if on cue, just days after SDO’s Atmospheric Imaging Assembly (AIA) was switched on, the Sun threw an epic fit, blasting out an arcing prominence perfectly positioned for us to see. A prominence is a loop of gas that erupts from the surface of the Sun. This gas follows the Sun’s magnetic field lines; complicated interplay between the energy stored in the field lines versus their tension causes them to leap up from the Sun, anchored in two spots that represent where the north and south poles of the lines punch through the Sun’s surface. A prominence might have as much as a hundred billion tons of matter in it, and can be hundreds of thousands of kilometers across.

To give you an idea of this, here’s a video made from images from AIA:

Kaboom! Interestingly, the gas isn’t as hot as you might think, and can be cooler than the surface of the Sun. When we see a prominence edge-on, silhouetted against the surface of the Sun, it actually appears dark! When that happens, we call it a filament.

I’ve been a big fan of the Solar and Heliospheric Observatory (SOHO) for a long time, and SDO is like the Son of SOHO. It has technology that is more current, and has very high resolution cameras. SDO can take spectra of the Sun to look in detail at its composition, temperature, motion, and magnetic strength. It can also measure the seismology of the surface of the Sun, the way waves travel across it and make it pulse; this tells us about the interior of the Sun that is otherwise totally invisible. Combining all this data together yields a vast amount of knowledge waiting to be learned about our nearest star.

It also produces stunning full-Sun imagery:


This image is amazing; it shows very hot helium and iron ranging in temperature from 60,000 Kelvin (100,000+° F) to well over a million Kelvins (1.8 million degrees F)! You can see the big prominence to the left, as well as several others around the disk. All the twisting and writhing on the surface is due to the bubbling convection of hot material from the Sun’s interior rising to the surface coupled with the fiercely complex solar magnetic field. The physics involved is incredibly complex, but with SDO’s help scientists will soon have a much firmer grasp on what’s going on.

Of course, they’ll also have a pile of new mysteries to ponder as well. The Sun is the closest star to the Earth, and closer than most planets. We know a lot about it, but there’s so much left to understand: what’s the root cause of the 5.5 year long solar magnetic cycle? How is that tied to Earth’s climate? What effect do sunspots have on the Sun and Earth? How exactly does the Sun influence space weather; the flood of subatomic particles streaming from the solar surface and interacting with our own magnetic field, affecting satellites and even our power grid?

Science is like a tapestry with no edge, and with holes located here and there in the fabric. We can fill those holes ever more, and explore the edges, pushing them back with each new discovery. Along with many other observatories like it, SDO is our loom that helps us create and follow that weave.


CATEGORIZED UNDER: Astronomy, NASA, Pretty pictures

Comments (41)

  1. Astrofiend

    This thing is going to be pants-creamingly good.

  2. Nuke3d

    Is “physics” singular or plural?

    Pretty awesun at any rate :)

  3. Monkey


    ….and awsome matters!!

    This is just amazing. Astronomy…the gift that keeps giving.

  4. rob

    new desktop background!

  5. Estarian

    Great images.. spectacular.
    BUT I can see with my mind’s eye the wooer’s wooing about the second one. HUUUGE titles in “alternative science-alien loons” blogs : THE SUN TURNS GREEN! PROOF! THE END IS COMING. 2012 IS CLOSE. etc etc..
    I m sure SOME loon will do this..

  6. Messier Tidy Upper

    Superb. Thanks SDO team & BA. :-)

    I saw some of these on the TV & print news before as mentioned on the first SDO video thread :

    but glad you’ve posted this too. :-)

    I can’t see that bit of dust that marred the other one here either which is good.
    But why is that? Did the “dust on the camera” (comment # 4 linked thread.) arrive later or has this been adapted to remove it or processed differently or what?

    Also : How much of the material in the prominence there would have escaped as solar wind and how much would have fallen back into /onto our Sun? Anyone care to enlighten us?

    @ 3. Nuke3d Says:

    Is “physics” singular or plural?

    Uh ..both I think. 😉

    (Then again I’m not renowned for grammar expertise.)

    @1. Naked Bunny with a Whip Says:

    Matter is awesome.

    Plus its transformation into energy is pretty impressive too! 😉

  7. Estarian

    Originally the word “physics” comes from greek “fisiki” -which is still the same word in modern greek(or I suppose you could spell it as “physiki” which is singular ,adjective and feminin and means “natural”. note that in greek the word would be pronounced not like you native english speakers would pronounce “i” as in “pie” but sharp. Like you pronounce the “i” in “be”. ) Wow, major linguistic comment here and I m not even good at this being a mathematician. (I m greek though, so at least the part about the origin of the word is true)
    So, to make a long comment short, the original greek word is singular, but I think the “s” in anglosaxon languages was added for petter “sound”, but I cant be sure about it.

  8. Chris

    @ Messier Tidy Upper
    “Plus its transformation into energy is pretty impressive too!”

    And multiply that by the speed of light, and well – you’ve REALLY got something! 😉

  9. Douglas Troy

    [begin pun-age]

    Wow. That’s hot. I mean, it really shines. I’d even say it’s a glowing example of what science is all about. Those pictures are explosive in the details they present and I was stunned at just how bright these folks are on this project and the light they’re shedding about our sun.

    [end pun-age]

    Oh, I’m sorry … I’ve been fusion for something funny to say.

  10. @Messier Tidy Upper: You’re just complicating matters. (Har.)

  11. Richard Woods

    “the root cause of the 5.5 year long solar magnetic cycle”

    Well, I learn something every day. Today, it’s that “The 11-year cycle of the large-scale solar magnetic field leads the 11-year sunspot cycle by, on average, 5.5 years.” (

    OTOH, I see that some folks are investigating an actual 5.5-year cycle, the second harmonic of the 11-year cycle. ( However, this refers to a 5.5-year cycle in sunspot numbers rather than in magnetic field.

    Phil, can you point us to some explanation of what you meant?

  12. I thought it was a 22 year cycle, with each 11 year part differing from the other by the overall magnetic parity. Silly me.

  13. Kelly

    Don’t forget that STEREO has an iPhone app called 3Dsun, which is sharing all of the SDO images (photo and video). It’ll alert you via phone when new and interesting things are going on. :-)

  14. jcm

    Off topic:
    Boston’s Big Picture of the oil rig accident off the coast of Louisiana.

  15. Bob Woolley

    You mention the “surface” of the sun eight times. My understanding has long been that the sun has no surface. Rather, there is a continuous gradient of gaseous density. Can you explain what you mean by “surface” in this post?

  16. MadScientist

    Ooooo – purdy! I was looking at the top pic thinking “so what could be new about this? We could get images like that from the ground 50 years ago.” I love that loop prominence – someone put a string through and hang that bauble on the christmas tree.

  17. captain swoop


    is that a cromulent word?

  18. Christina

    It was originally borrowed into English as “physic”. I think the -s came about through it being seen as a body of sciences rather than just one, but that’s just a guess

  19. Mike

    it is not ‘gas’ it is electrically charged plasma.. and the reason it seems to follow magnetic vectors is because moving charged particles in a plasma constitute an electric current, and electric currents are always accompanied by a magnetic field at right angles (Amperes Law). It is not complex at all, it is basic high school physics.. The mystery is how astronomers routinely forget these basic physical principles and pretend the 4th state of matter equals the 3rd.

  20. Mke (#21): Oh, real scientists know what a gas and plasma are. What you Electric Universe proponents don’t seem to understand is that you need charge separation to get a current. The magnetic field of most plasma discharges from the Sun have their magnetic field embedded in them, but they are overall electrically neutral.

    The very fact that you think highly-trained scientists don’t understand high school physics should give you a tiny clue that maybe your supposition is wrong.

  21. Emma McKay

    Absolutely gorgeous stuff. I’m seriously jumping in my seat waiting for news on the magnetic field. =)

  22. James Abbatiello

    I can’t be the only person to be reminded of

  23. Leonard


    Please answer the question in #12.


  24. that is hawt with a W

  25. 17. Bob Woolley Asks: “You mention the “surface” of the sun eight times. My understanding has long been that the sun has no surface. Rather, there is a continuous gradient of gaseous density. Can you explain what you mean by “surface” in this post?”

    Generally, the “surface” of the sun is the part called the photosphere, the layer that emits the light that we see. This is the first opaque layer, so we can’t see below it and the ones above it are (obviously) transparent, at least in visible light.

    – Jack

  26. Jack Mitcham

    Thanks for the new desktop wallpaper, Phil!

  27. “Science is like a tapestry with no edge, and with holes located here and there in the fabric. We can fill those holes ever more, and explore the edges, pushing them back with each new discovery. Along with many other observatories like it, SDO is our loom that helps us create and follow that weave.”

    Ah, THERE’s the poetry. I knew it.

  28. I was also “away from my computer” when these were released and had to wait to see them! But yeah…..crazy cool stuff. Love how the prominence twists as it tears away from the Sun!!!

  29. Just me

    I’m curious. So, is it 60,000 Kelvin, or 60,000 degrees Kelvin? I’ve heard it both ways—and I’ve always heard it “corrected” as 60,000 Kelvin (sans “degrees”). Science is confusing.


    @ Just me (#31),

    From Wikipedia — Kelvin (Usage conventions):

    Until the 13th General Conference on Weights and Measures (CGPM) in 1967–1968, the unit kelvin was called a “degree”, the same as with the other temperature scales at the time. It was distinguished from the other scales with either the adjective suffix “Kelvin” (“degree Kelvin”) or with “absolute” (“degree absolute”) and its symbol was °K. The latter (degree absolute), which was the unit’s official name from 1948 until 1954, was rather ambiguous since it could also be interpreted as referring to the Rankine scale. Before the 13th CGPM, the plural form was “degrees absolute”. The 13th CGPM changed the name to simply “kelvin” (symbol K). The omission of “degree” indicates that it is not relative to an arbitrary reference point like the Celsius and Fahrenheit scales, but rather an absolute unit of measure which can be manipulated algebraically (e.g., multiplied by two to indicate twice the amount of “mean energy” available among elementary degrees of freedom of the system).

    (My emphasis.)

  31. JGH-4774
  32. Damon

    All I see is a Quicktime logo.

  33. Just me

    @ IVAN3MAN (#32)

    Heh. I guess if I’d learned to use teh internets properly, I could have looked that up myself. 😉 But thanks for the clarification, IVAN!


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar