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Thermosphere Contraction Puzzles Scientists 200

Posted by Soulskill
from the chicken-little-knows-what's-up dept.
The thermosphere layer of earth's atmosphere begins 80 to 90 kilometers above the surface and extends several hundred kilometers into the sky; it is the home to numerous satellites and the International Space Station. It is known that the thermosphere occasionally cools and contracts, but a recent study of satellite orbital decay (due to light atmospheric drag) found that the contraction during 2008 and 2009 was significantly more severe than expected, leaving researchers at a loss for how to explain it. From Space.com: "This type of collapse is not rare, but its magnitude shocked scientists. 'This is the biggest contraction of the thermosphere in at least 43 years,' said John Emmert of the Naval Research Lab, lead author of a paper announcing the finding in the June 19 issue of the journal Geophysical Research Letters. 'It's a Space Age record.' The collapse occurred during a period of relative solar inactivity — called a solar minimum from 2008 to 2009. These minimums are known to cool and contract the thermosphere, however, the recent collapse was two to three times greater than low solar activity could explain."
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Thermosphere Contraction Puzzles Scientists

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  • by IANAAC (692242) on Saturday July 17, 2010 @12:55PM (#32937532)
    It'll end up being a blamefest.

    The first 4 comments show as much.

  • by Karganeth (1017580) on Saturday July 17, 2010 @12:57PM (#32937542)
    The sky is falling in... literally!
  • "Don't worry, it's cool."

    "Don't worry, I suffer from a bit of shrinkage, too."

  • I'm confused. (Score:5, Insightful)

    by slasho81 (455509) on Saturday July 17, 2010 @01:01PM (#32937564)

    On the one hand, it's reported this is not rare. On the other hand, we've got plenty of sensationalistic language: "significantly more severe", "researchers at a loss", "collapse", "its magnitude shocked scientists".

    So, is it the usual news cycle hype reporting on a puzzling phenomenon, or is there a reason to be alarmed?

    • First rule: If you can’t change it, and can’t protect yourself from it, there is no point in being alarmed.

      • by Barrinmw (1791848)
        Global warming is like old age, when you are young you might worry a little about death. When you get middle aged, you really worry about death. When you get old, meh, Death? Can't wait to meet him. As we get closer we will come to realize it all ain't that bad.
        • From what I can tell, that happens mainly to old people who spend their retirement time watching TV.

          Saramago (our laureate writer) said he was afraid of dying not because of death itself, but for all the projects he was still committed to and would leave unfinished.

        • "When you get old, meh, Death? Can't wait to meet him. As we get closer we will come to realize it all ain't that bad."

          Thats called rationalizing. Old people if they had the option to die or swap into a young cadaver and live healthily for another 50years would take it. And they would not like the idea of death all over again.
          • by Barrinmw (1791848)
            Or some people feel old and are ready for their time to be up, "...like butter spread over too much bread"
  • Damn. (Score:2, Interesting)

    by BrokenHalo (565198)
    I was hoping for some comment that might shed some (presumably ionising) light on this issue, since TFA offers no suggestions. Instead, we have a series of boring troll posts.

    Oh well, I'll just move on, nothing to see here...
  • WTF? (Score:3, Funny)

    by gbutler69 (910166) on Saturday July 17, 2010 @01:04PM (#32937578) Homepage
    The sky IS falling. Oh, Chicken Little, how we all should've listened!
  • by phantomfive (622387) on Saturday July 17, 2010 @01:05PM (#32937584) Journal
    Actually it's likely related to global warming, since CO2 emits light at a different wavelength than it absorbs it, it sometimes causes the thermosphere (and other layers) to cool and contract by the time the light gets to the outer layers. There are climate models that predict this. The heat is absorbed at low altitudes and not emitted at high altitudes.

    Actually I just made that up, but it sounded good, didn't it? Right? I'm sure we can blame it on pollution somehow.
    • by TheSHAD0W (258774) on Saturday July 17, 2010 @01:10PM (#32937610) Homepage

      Evil. Very evil.

      You have a lucrative future ahead of you in climatology.

    • Re:actually it's (Score:4, Informative)

      by Bigjeff5 (1143585) on Saturday July 17, 2010 @01:36PM (#32937748)

      Actually it's likely related to global warming, since CO2 emits light at a different wavelength than it absorbs it, it sometimes causes the thermosphere (and other layers) to cool and contract by the time the light gets to the outer layers. There are climate models that predict this.

      The problem with that is the CO2 levels have been gradually rising over the years - the 2008-2009 cycle did not have significantly more CO2 in the atmosphere than did previous cycles, yet there is a massive difference thermosphere compression.

      If CO2 were the cause you would still expect to see a gradual increase in thermosphere compression year to year - the current 16 year cycle would simply have a higher rate of compression on average than the previous solar cycles.

      That's not what was observed. What was observed was a massive compression in a single year - far greater than the previously useful solar models predicted. CO2 can definitely be part of the cause, but it cannot explain the huge difference between 2007-2008 and 2008-2009. They should only differ by the difference in solar activity, as CO2 levels are essentially the same.

      • by nadaou (535365)

        ... because all natural systems respond in a strictly linear fashion?

        umm, no.

    • why is gp troll?
    • by ultranova (717540)

      Actually I just made that up, but it sounded good, didn't it? Right?

      Yeah, you sure earned your paycheck today. I guess astroturfing pays well if you don't have a problem with lying, eh?

    • by Xyrus (755017)

      Actually, no.

      I know you were trying to be tongue-in-cheek but increased CO2 levels are not going to have much effect on the thermosphere to the level that they're seeing. Sure, a higher greenhouse content in the troposphere will have some impact due to successive cooling of the higher atmospheric layers, but there is hardly any atmosphere at those levels anyway. In addition, the change they saw was year over while global warming takes place over decades.

      Unless the warming caused some sort of critical level

  • ARRL skip thought (Score:2, Interesting)

    by moo-shim (1335425)
    I wonder that the Amateur Radio low power operators have to say about the "skip" signals? That is when a radio wave gets caught in a "corridor" up there and "bounces" in there a long way before coming back to earth. The compression should have some sort of effect on them.
  • by kaoshin (110328) on Saturday July 17, 2010 @01:53PM (#32937840)
    It is an interesting to me that the HAARP project [wikipedia.org] was brought online a year before these severe contractions of the thermosphere. Although I'm sure the conspiracy theories are over the top, it would probably be dumb to disregard the fact that there are no other explanations right now as to what is happening to the atmosphere, but during this time period the military just happened to conduct an experiment against it.
  • by White Flame (1074973) on Saturday July 17, 2010 @03:56PM (#32938502)

    when the contractions are 5 minutes apart

  • by SETIGuy (33768) on Saturday July 17, 2010 @10:00PM (#32940478) Homepage

    The temperature of the thermosphere has nothing to do with the temperature of the climate. We're talking about the part of the atmosphere where the international space station orbits. The rules there are very different from the lower atmosphere (as are the temperatures (up to a few thousand C depending upon where you are). The temperatures are controlled by the absorption and emission of radiation (and, of course, conservation of energy).

    The radiation absorbed by these tenuous gasses is in the extreme ultraviolet and soft x-ray. We've been monitoring the solar EUV and SXR output for quite a while. When they are high the thermosphere heats up and expands. Satellites in low orbit experience a lot of drag and end up in lower orbits. Because of the extended solar minimum EUV and SXR are way down, but they haven't changed enough to explain the entire temperature difference. So the remainder of the difference has to be in the emission of radiation in the thermosphere. There's a series of linked partial differential equations involved, so I won't do the actual math. But the easiest way to cool the thermosphere is to add higher amounts of species that have a lot of cooling transitions.

    One of the people quoted in TFA thinks it might be due to increased CO2. I have a hard time buying that. Because it's heavy, it's hard to get CO2 into the thermosphere. It would be tough to get an in situ measurement of CO2 and it's ionization products with any existing instrument

    As far as what this effect could do to the world. Well, it could screw up your AM reception. And it could screw up a prediction of a LEO satellite's orbit. (i.e. your sun synchronous polar orbit might not be as sun synchronous as you hoped.) But it's not going to kill dolphins or sea turtles, or cause earthquakes or polar shifts.

    I could do the required measurement with an FUV to NUV spectrometer for diffuse radiation on 2-axis coarse pointing gimbal. I'd need a satellite for a platform. But by the time I got it built and launched we'd be heading up toward solar max.

    Disclaimer, I do this for a living.

    • One of the people quoted in TFA thinks it might be due to increased CO2. I have a hard time buying that. Because it's heavy, it's hard to get CO2 into the thermosphere. It would be tough to get an in situ measurement of CO2 and it's ionization products with any existing instrument[.]

      I think the quote was referring to CO2 in the lower atmosphere trapping thermal energy there and keeping it from reaching the upper atmosphere. This effect cools the upper atmosphere and the thermosphere, causing contraction.

  • The Global Financial Crisis - no one could afford a Thermosphere.

If I had only known, I would have been a locksmith. -- Albert Einstein

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