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Staring at the sun
April 16, 2007 5:38 PM   Subscribe

Staring at the sun. YouTube video of solar flares, made from images captured by the SOHO satellite. Yes, there is more.
posted by Brandon Blatcher (25 comments total) 11 users marked this as a favorite

 
That was really amazing. Thanks a lot.
posted by kbanas at 6:04 PM on April 16, 2007


awesome

oh, and:

The sun is a mass of incandescent gas
A gigantic nuclear furnace
Where hydrogen is built into helium
At a temperature of millions of degrees

posted by spikeleemajortomdickandharryconnickjrmints at 6:04 PM on April 16, 2007


The imagery SOHO has been producing is just freaking transcendent.

What's with the soundtrack though? Don't you know the music of this particular sphere?
posted by gwint at 7:00 PM on April 16, 2007


Oh, also, if you're a heliographophile, you might be interested in the upcoming Sunshine.
posted by gwint at 7:05 PM on April 16, 2007


I guess I shouldn't have stared so long.
I guess I shouldn't have stared so long.
Cuz now I can't see at all! *rock out*
posted by Eideteker at 7:09 PM on April 16, 2007


This is lovely. Thanks so much - I really needed a thread like this today.
posted by dog food sugar at 7:10 PM on April 16, 2007


Staring at the sun
posted by hortense at 9:37 PM on April 16, 2007


What's with the soundtrack though? Don't you know the music of this particular sphere?

I knew the sun was into Radiohead!
posted by katillathehun at 9:43 PM on April 16, 2007


The imagery SOHO has been producing is just freaking transcendent.

It was planned as a two year mission -- starting in May of 1996.

Still works, mostly. They lost pointing control of the bird in 1998, causing it to lose point on the sun, and they hydrazine fuel tank froze. They managed to get the bird back. They lost the ability to point the high gain antenna, but they figured out how to get medium rate telemetry off the bird 100% of the time, and high rate data most of the time, mod small blackout periods every six months. They also have to rotate the bird 180 degrees to do so, so every six months, you have to flip the sun.

The CCDs are full of flaws from over ten years of solar activity, and have to be baked out every six months. Funny how they synchronize that with the data loss time.

The damn thing didn't even launch with a roll of gaffer tape, and yet, they still keep it running. We need to replace it -- this is the kind of bird that if you could satellite service contracts, they'd just laugh at you before saying "no."
posted by eriko at 5:03 AM on April 17, 2007 [1 favorite]


Since I was actually the mission planner for TRACE (the Transition Region and Coronal Explorer) when we observed many of those events, I have to point out a couple of things.

First, most of what you see is actually from TRACE, not SOHO. SOHO's images are mostly full-sun, and all are lower resolution than the TRACE movies where you see those individual loops.

Second, a lot of what you see in that movie aren't solar flares, but simply the natural evolution of the sun's atmosphere, the solar corona. Flares, like the massive one that they show about 2 minutes into the video, are very high-energy, impulsive events. Most of these are simply plasma getting slowly heated to about a million degrees. When it reaches this temperature, it starts to emit radiation to which this particular TRACE passband is sensitive and it lights up. Because plasma in the solar corona is confined to individual magnetic field lines and can't flow across them, individual loops get heated separately from their surroundings, and you see only individual loops light up. Nonetheless, the corona is permeated by both magnetic field and by plasma which is invisible to the spacecraft cameras.

Movies from the X-Ray Telescope on the new Hinode Spacecraft, which is sensitive to a wider range of temperatures than TRACE, show much broader features, because you don't see only plasma of a single particular temperature.
posted by dseaton at 7:27 AM on April 17, 2007 [13 favorites]


Dan, thanks for chiming in.

If you got a moment, I got a couple of questions. What does a mission planner do? Did you come up with the idea for the satellite? Do you decided what instruments go on it? Do you decide which don't? Were you the only mission planner or the head planner? Did you design any of the instruments aboard it? What other missions have you been involved in? Is solar study your specialty?
posted by Brandon Blatcher at 9:25 AM on April 17, 2007


Since there's a whole freakin' MeTa thread about my comment, I thought I would add a couple of details. First, I was not the only mission planner for TRACE -- just one of a whole crew who each took week-long shifts as planner once every two or three months. It just happens that I got the week of April 15-21, 2002, (among other times) and decided to point the satellite at a kind of promising region that was soon to rotate out of view. We ended up seeing one of the more weird and interesting events that TRACE ever observed. Here are the planning meeting notes from that week. (Actually, I assume that we pointed at the region where that amazing flare happened because the Max Millennium people -- who coordinate joint observations of potentially interesting solar regions by many spacecraft -- told us to.)

I was kind of jumpy, actually, about the program for that weekend, because on a recent planning run a couple of weeks before I had made a command error that put the telescope into Safe Mode (which basically means it shuts down to prevent damage). People were pretty annoyed by that, so I was checking up regularly on the data, making sure it was coming down from the spacecraft smoothly. And then on Sunday evening we started seeing these completely amazing pictures. Actually, that flare and, in particular, the weird downflows that occur above the bright loops in the movie, has been the primary focus of my research ever since. So it's kind of cool to see it show up on metafilter, randomly, one day.

By the way, there's a better quality movie of the big flare from the original post. There's also a whole archive of interesting observations from TRACE that you can visit.

On Preview: I see there are questions now. I'll answer them, but I have to go to a meeting. (No, not about space, unfortunately, just university politics.) I'll comment further once I have a chance.
posted by dseaton at 9:26 AM on April 17, 2007 [7 favorites]


pretty nifty, thanks.
posted by Smedleyman at 11:20 AM on April 17, 2007


Answers (in the past tense not because TRACE no longer operates -- it does -- but because I don't work on it anymore):

What does a mission planner do?

I can't comment on the operations of any other spacecraft than TRACE, because that's what I worked on. I know a lot of the operations people for Chandra -- who had offices just down the hall from me -- had beepers and were often on 24-hour call, so apparently some missions require considerably more involvement from the ground than ours did.

In general, the TRACE science operations team -- which was spread around the country -- would hold a once-weekly telecon to discuss the plans for the next week or so. The planner for the week would explain what their basic plan was, and the head guys would talk about what we were required to observe to support certain joint operations and special observer requests, then we'd sort of delegate all the free time out to whoever wanted it. Sometimes the planner would use the free time to make observations for a pet project, sometimes someone on the science team would request a certain kind of observation.

Then, the week you were actually planning, every day you'd come in, see what the sun was doing, and decide whether to follow the plan from the telecon or go to a special target, like a region that looked particularly ripe for a flare or something. You'd check the spacecraft to make sure it was operating normally, then figure out the coordinates on the sun of anything you wanted to point to. After that you would fire up this absurdly complicated and archaic program that actually made the instructions -- called the timeline -- for the satellite computer. You'd enter all the instructions for observing into the timeline, check to make sure that you hadn't designed a sequence that was going to overflow the spacecraft's memory, and add whatever notes (for the science team if they read the timeline) you thought were necessary, and sent it off to the Experiment Operations Facility (EOF) people at Goddard Space Flight Center. Here is an example of an actual timeline -- the one I made for that giant flare.

Then you would call the EOF and tell them that the timeline was read to be beamed up to the satellite at the next opportunity. You'd send out a couple of emails announcing the plans for the next day, and you were done for the day and back to doing your regular work.

Did you come up with the idea for the satellite? Do you decided what instruments go on it? Do you decide which don't? Did you design any of the instruments aboard it?

No. I was still in college when TRACE was designed. Credit for TRACE's design goes mostly to the people who wrote this paper, which provides a very detailed discussion of how it operates and citations to many very technical articles about its design.

What other missions have you been involved in?

When I was still working at the Harvard-Smithsonian Center for Astrophysics, I worked on some of the design and engineering aspects of the XRT on Hinode. Now I'm a member of the XRT Science Operations team.

Is solar study your specialty?

Yes, although that's a pretty broad term. I'm particularly interested in the processes that cause solar flares and other eruptions in the solar corona.

Sorry for kind of co-opting/derailing this post -- I only meant to provide some context for the movie. I hope this long description of space operations arcana was interesting to somebody.
posted by dseaton at 11:50 AM on April 17, 2007 [3 favorites]


Don't apologize, I for one welcome our new love these intricate ops details. I have a friend who's involved in the ISS and I bug him constantly about little details like this. Like I tell him weekly, you space guys need blogs, badly.
posted by Skorgu at 12:30 PM on April 17, 2007


I hope this long description of space operations arcana was interesting to somebody.

I was on the SOHO Flight Ops Team from 1996 to 1999, so I found your comment interesting. I'm working on my sixth spacecraft right now, but I often think of SOHO.
posted by Fat Guy at 12:31 PM on April 17, 2007


I know a lot of the operations people for Chandra -- who had offices just down the hall from me -- had beepers and were often on 24-hour call, so apparently some missions require considerably more involvement from the ground than ours did.

As I understand it, the universe is quite a bit more dynamic in x-ray than in the visible - changes happen on a weekly or even hourly basis. There's a global alertnet involving all the x-ray observatories in the world, and if some interesting thing gets observed by one satellite a notice gets broadcast so that all the others can join in on the observation.
The mission planners are therefore needed to be ready almost all the time so they can drop what they are doing and race to get their satellite to point at the event, which may not happen for very long.
I'm not someone who is involved professionally, I'm just a nerd :)
And dseaton I'm glad that someone like you is reading and posting on mefi( and on preview, you too Fat Guy :)). I saw a presentation about the first imagery from Hinode on Nasatv and it was very spectacular. The XRT is a kind of evolvement of the xray mirrors on Chandra isn't it?
posted by Catfry at 2:22 PM on April 17, 2007


...the universe is quite a bit more dynamic in x-ray than in the visible - changes happen on a weekly or even hourly basis.

The same is true for the sun, which is arguably more dynamic than any other astronomical object. With TRACE, I think we didn't do on-call planning largely because it was impractical -- you only get a couple of dish passes a day with which to upload a new program, so even under the best of circumstances, you probably couldn't respond to an event faster than about 12 hours anyhow. I don't know if the situation is different for Chandra, but one possibility is just that it was easier to talk to that spacecraft than it was to talk to TRACE.

The XRT is a kind of evolvement of the xray mirrors on Chandra isn't it?

Without getting too technical, XRT and Chandra both use Wolter I telescopes. X-Rays are just too energetic to bounce off of a regular mirror like visible light does; they'll pass right through it. Instead, you have to skip the x-rays off the mirror surface like you would skip rocks on a pond. We call this kind of telescope a grazing incidence telescope (as opposed to a tradition normal incidence telescope where the light hits normal -- perpendicular -- to the mirror). I don't know enough about Chandra to say how closely the optics are related, but it's certainly true that these telescopes are very similar.
posted by dseaton at 3:26 PM on April 17, 2007


Yeah, the question were already forming in my mind why you didn't do the same thing as i posted my comment. I guess Chandra is dedicated alot more up and downlink time since it's one of the 'major' observatories.
posted by Catfry at 4:17 PM on April 17, 2007


I have read an account of the quickest targetting reaction operations going on with the gamma ray observatory INTEGRAL and if you're interested it can be read here (scrool down to the yellow box).
posted by Catfry at 4:34 PM on April 17, 2007


Sorry for kind of co-opting/derailing this post -- I only meant to provide some context for the movie. I hope this long description of space operations arcana was interesting to somebody.

Are you kidding me? Us geeks live for this kind of stuff. Thanks for your work and insider comments, dseaton (you, too, Fat Guy).
posted by Civil_Disobedient at 5:00 PM on April 17, 2007


As someone whose ambition to work on stuff like this hasn't been totally squashed just yet - thanks!
posted by casarkos at 5:38 PM on April 17, 2007


Also see my FPP on this a while ago for more.
posted by BlackLeotardFront at 6:36 PM on April 17, 2007


BlackLeotardFront: I don't know how I missed your FPP from last summer. If I had, I would have derailed that one instead.

(Nice post, seriously. I'm always glad to see TRACE get some attention.)
posted by dseaton at 7:52 PM on April 17, 2007


Oh, it just got lost in the crush, that happens sometimes. I'm just glad I had the reason to make the post - the TRACE site is fantastic and full of great stuff.

Thanks a lot to you for helping make that all happen!
posted by BlackLeotardFront at 12:32 AM on April 18, 2007


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