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Earth Space

Space Is Just a Little Bit Closer Than Expected 130

Posted by timothy from the winter-shrinkage dept.
SpuriousLogic points out a BBC story which begins "The upper reaches of Earth's atmosphere are much lower than expected, a US Air Force satellite has found. Currently, the ionosphere — a layer of charged particles that envelopes the planet — is at an altitude of about 420km, some 200km lower than expected. The behaviour of the ionosphere is important because disturbances in its structure can upset satellite communications and radar."
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Space Is Just a Little Bit Closer Than Expected More

Space Is Just a Little Bit Closer Than Expected

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  • Wow (Score:5, Funny)

    by IceCreamGuy ( 904648 ) on Tuesday December 23, 2008 @09:55AM (#26211455) Homepage
    skyisfalling tag has never been so accurate!

  • interesting (Score:5, Funny)

    by Technopaladin ( 858154 ) on Tuesday December 23, 2008 @09:57AM (#26211465)

    Thats a pretty wide margin of error.

    Things in the Ionosphere can be closer then they appear.

  • Odd (Score:1)

    by jav1231 ( 539129 )
    It's amazing how we look out into space and note the minutest changes and this happens at our back door. I picture a guy looking through a huge telescope at a far flung constellation. Then, wishing to take notes, leaning back and gasping, "Now where's my pen!?"
    • Yeah, amazing. That guy has a huge telescope, but no computer to write notes on.

      • Re: (Score:2, Offtopic)

        by MBGMorden ( 803437 )

        Depending on the situation it's not comfortable for everyone to take notes on a computer. I type very fast (between 90 and 120 wpm depending on how complex the words are), but if I am looking to just jot down information I still prefer pen and paper. It's free form, I can draw lines and make connections quicker, etc. For anything relevant I'll go back and transcribe my notes into text/digital form later. I've met quite a few other people who have similar feelings.

      • Re: (Score:2)

        by jav1231 ( 539129 )
        No see the pen corresponds to the ionosphere. Thus noting close proximity and therefore familiarity hence it should be well understood...and....
        you know what? He should have taken notes on the computer. *sigh*

  • So... (Score:2, Funny)

    by Anonymous Coward

    ...the current satellites may be working just by chance?

  • how could we not have already known this? (Score:2, Interesting)

    by Anonymous Coward

    shouldn't we have already known this? this seems like really, really fundamental data.

    • Re: (Score:2, Informative)

      by Quantumstate ( 1295210 )
      It does seem surprising given that the ionosphere was used to bounce radio waves around the earth when satellites were not available.

  • Obligatory (Score:5, Funny)

    by Revotron ( 1115029 ) * on Tuesday December 23, 2008 @10:04AM (#26211527)

    Chicken Little, after many years of mockery, finally has the last laugh.

  • below 30MHz (Score:5, Interesting)

    by FudRucker ( 866063 ) on Tuesday December 23, 2008 @10:07AM (#26211547)
    HF propagation is effected too...

    • Re: (Score:2, Informative)

      by Anonymous Coward

      Yes, HF propagation is affected -
      primarily by the dearth of sunspots...

      20m was kind of lousy on Sunday, 'tho I did hear a weak ZS6 here in SoFla.

      It will be interesting to see if they repeat these ionospheric measurements regularly, say monthly, over the next 2-3 years as the next cycle starts (to start) up... maybe...

    • Yup. That's why you generally use a higher freq during the day and a lower freq at night...

  • Erosion of the ionosphere? (Score:5, Funny)

    by BadAnalogyGuy ( 945258 ) <BadAnalogyGuy@gmail.com> on Tuesday December 23, 2008 @10:08AM (#26211571)

    If this is an actual erosion of the ionosphere, we may be looking at a serious problem. Whereas a hole in the ozone only amounts to a net increase of UV radiation (not that that is any good for humans), a thinner ionosphere means more solar wind removing our planet's atmosphere. Enough erosion and we'll be more barren than Mother Theresa at a Gay Pride festival.

    • Re: (Score:3, Funny)

      by David Gerard ( 12369 )

      Where's the car? We need cars!

      A good bad car analogy is: the ionosphere is like a Trabant, with an engine spewing out all manner of charged particles wrapped in a thin shell at best. And the effect being seen is like a stretch Trabant [today.com], as the thin shell is pulled beyond its limits. A pink one.

      A stretch Trabant is also what government-subsidised car makers would result in, resulting in worse ionosphere damage. Perfect!

      (Further) Off-topic: here's a heavy-duty Trabi mod: a V8 Trabant [oddrods.co.uk]. They basically had

    • Re: (Score:3, Interesting)

      by Reziac ( 43301 ) *

      Actually, I had roughly that thought... "Did they measure its distance wrong the first time, or did it move closer to the surface??"

      And if the latter... why? is it a temporary condition as the ionosphere flexes up and down, or a permanent trend? And if the latter, hasn't it moved awfully fast?? Unfortunately we don't have the longterm data to determine it either way... and I mean millions of years worth. A few tens of thousands may be meaningless on the scale of atmosophere/space interactions.

      Stands as evid

      • Re: (Score:2)

        by lgw ( 121541 )

        Or it may well be evidence that "global warming" is a distraction from the real extinction event: the disappearance of the Earth's magnetic field. While I'm not to worried about either event, it always seemd odd to me how little press Earth's magnetic field reversal gets (with the accompanying time of no significant field at all). Perhaps the slow change, plus the fact no one really uses compasses for navigation much, have kept it non-news, but I rather expect that no one has yet found a way to use "magne

        • Re: (Score:2)

          by Reziac ( 43301 ) *

          Astute observation. Imagine if someone seized on the cult of "man's use of iron is hastening the magnetic field reversal!"

          • Astute observation. Imagine if someone seized on the cult of "man's use of iron is hastening the magnetic field reversal!"

            My friend, I think you just solved the mystery of the Baigong Pipes [wikipedia.org].

    • A thinner or closer ionosphere does not relate to scouring of the atmosphere by the solar wind. It is the Earth's natural magnetic field that protects the atmosphere from being stripped away by the supersonic solar wind.

      A pending reversal of the Earth's magnetic dipole may somewhat increase atmospheric scouring, but you must remember that only the dipole moment is going to reverse direction. The higher order (e.g. quadrupole) moments won't go anywhere and will still deflect the solar wind. You'll just g

  • She's gone from suck to blow! (Score:5, Funny)

    by millisa ( 151093 ) on Tuesday December 23, 2008 @10:15AM (#26211623)

    Has anyone noticed any large maid-like robotic entities in orbit? More importantly to our future, were there any winnebagos with wings nearby?

  • Wow! (Score:1, Insightful)

    by Anonymous Coward

    I'm suddenly almost halfway towards my goal of making it into space. Take THAT everyone else at the class reunion!

  • Comment removed based on user account deletion
  • Now we know why the Earth is warming. We've just got less atmosphere to hold all the heat.

  • WTF??? (Score:5, Insightful)

    by Nom du Keyboard ( 633989 ) on Tuesday December 23, 2008 @10:29AM (#26211765)
    WTF? We've been launching rockets for 50 years to probe the space around us and they're only figuring this out now?

    Or has this changed from before?

    • Re:WTF??? (Score:5, Informative)

      by FailedTheTuringTest ( 937776 ) on Tuesday December 23, 2008 @10:42AM (#26211869)

      It's changed. From the fine article: "We are in the depths of a very low solar minimum right now and as a result the ionosphere is lower and less dense than, we believe, at any other time in the history of the space age..."

    • The ionosphere moves. In fact it changes daily and is differnt at night and day and it depends on solar activity. It is a bit like sunlight it too changes (it get dark at night, some times there are clouds and soe times not) but still it makes sens to say "It's brighter then I thought it would be" that is wht they are saying here "It's lower than I thought it would be"

  • For a given value of ionosphere, and of Space (Score:5, Informative)

    by DynaSoar ( 714234 ) on Tuesday December 23, 2008 @10:34AM (#26211795) Journal

    I've never seen a definition of "space" that was based on the altitude of the ionosphere before. I've never seen a claim that the ionosphere was at a certain altitude, rather than a range with upper and lower bounds before. Most articles I see give about a 500 to 600 km altitude range, such as http://www.dcs.lancs.ac.uk/iono/ionosphere_intro/ [lancs.ac.uk]

    Still, that's the ionosphere, not "space", and it's subject to wide variations of many different periods. TFA fails to show whether the result is a permanent feature or simply the measurement they found. It can hardly be anything other than the latter because there have been many, many measurements of the ionosphere, starting with numerous sounding rockets during the International Geophysical Year, 1957-58. TFA fails to account for their one results being at odds with many others.

    And by "space" they mean "outer space", ie. outside the earth's atmosphere. If they meant simply "space", it could be the simple Euclidian definition of 3 extent dimensions. As such, we all exist in "space".

    • Real title. (Score:5, Funny)

      by Thanshin ( 1188877 ) on Tuesday December 23, 2008 @10:59AM (#26212075)

      And with "just" they may be referring to the justice meaning. As in "Space's Justice is closer than expected". And "bit" might be about the binary unit, as in "it's a 1 closer or 0 closer.". Finally, the term "closer" could be about the baseball relief pitcher who closes the game.

      So, for all we know, the title could perfectly mean:

      "Euclidean's three extent dimensions are applying justice a little one or an equally little zero, relief pitcher who finishes the game, than expected"

    • Re:For a given value of ionosphere, and of Space (Score:4, Informative)

      by Doctor_Marc ( 921485 ) on Tuesday December 23, 2008 @01:29PM (#26214069)

      Actually the choice of that wording was determined by the folks helping us with the press conference at AGU. Most folks don't even know what an ionosphere is, so we had to go with something that would at least give the average reader (not the Slashdot reader) a concept to start with. The BBC article did a good job of explaining the science and the concepts once you get past the headline.

      There is no universally agreed-upon definition of "where space begins." What we were reporting is that the "transition height" or "topside" in the ionosphere, the altitude where the density of O+ and the density of the light ions (H+ and He+) are equal, is lower than we have ever seen before. Here's a link for the definitions of these layers:

      http://www.ngdc.noaa.gov/stp/IONO/ionostru.html [noaa.gov]

      Note that above this level we don't have much interference with radio communications, so the practical interest is with the ionosphere below this altitude. Also this site points out that the topside rarely is below 500 km on the nightside, but the C/NOFS results show that it's currently almost always below that height (down to 400 km in places) .

      Here's a link to the press release that went with this press conference that gives a bit more information and a nice graphic of the topside measured by the CINDI instrument on C/NOFS.

      http://www.utdallas.edu/news/2008/12/16-001.html [utdallas.edu]

      (Full disclosure: I am a member of the CINDI-C/NOFS project.)

      • Re: (Score:1)

        by hcpxvi ( 773888 )
        Come on, mods, mod the parent up already. I am an atmospheric scientist and I had read TFA, but until I read the parent post I was completely in the dark as to what the story was actually about. The parent not only explains what the story was, but also has links to other pages which are not just drivel which has passed through too many journalists to mean anything.
    • What's somewhat related and very interesting is that the space shuttle often flies in the 200-300 km range of altitudes. We consider that "space", but it's right in the heart of the ionosphere in most places.

      It's all a matter of perspective.

  • GPS (Score:5, Informative)

    by Detritus ( 11846 ) on Tuesday December 23, 2008 @10:40AM (#26211841) Homepage
    An accurate model of the ionosphere is also important for GPS. GPS works by measuring the propagation delays of radio waves, which are affected by the Earth's atmosphere.

    • Re:GPS (Score:4, Informative)

      by digitig ( 1056110 ) on Tuesday December 23, 2008 @11:40AM (#26212577)
      It doesn't have to be that accurate a model for GPS. Yes, the atmosphere introduces errors into the propagation delays, but those errors are measured and accounted for. Ionospheric delays vary with the square of the frequency, so now two GPS frequencies are available for civilian use it's easy to adjust for ionospheric delays moment-by-moment, wherever the ionosphere happens to be at the time. Tropospheric delays are more of a problem, and are a significant part of the residual GPS error, but if the accuracy matters to you then you can use differential GPS and measure those delays too, moment by moment, and correct for them, whatever the troposphere happens to be doing at the time.

  • Metric vs Imperial (Score:4, Interesting)

    by bangzilla ( 534214 ) on Tuesday December 23, 2008 @10:40AM (#26211845) Journal
    Are we sure that they measured the distance in KM - what if it was miles, or furlongs, or rods, or perches....? I understand that this type of mistake has happened in the recent past.

  • Charades (Score:5, Funny)

    by greg_barton ( 5551 ) <greg_barton&yahoo,com> on Tuesday December 23, 2008 @10:41AM (#26211857) Homepage Journal

    This reminds me of a party and a game of charades. To be perverse I decided to have my charade be "ionosphere" figuring I'd stump everybody and wouldn't be bugged anymore about playing.

    Wouldn't you know it? Somebody guessed it in 15 seconds. Yeah, I hadn't counted on a radar systems engineer being at the party. :)

  • Atmospheric depth and temperature (Score:5, Informative)

    by RobotWisdom ( 25776 ) on Tuesday December 23, 2008 @10:45AM (#26211901) Homepage

    Even textbooks on this topic don't usually spell out the very simple dependence between atmospheric depth and surface temperature: when you warm the Earth, air molecules 'bounce' higher, so the atmosphere gets deeper. When you cool it, they bounce less high. The higher they fly, the slower they move, unintuitively termed 'adiabatic cooling'.

    A small percentage of the highest bouncers can be reheated by the Sun near the top of their bounces, and I assume the reported lower ionosphere is more due to a decline in this factor than to any global cooling.

  • "... because disturbances in its structure can upset satellite communications and radar"
    They say nothing about disturbance in the Force. IMHO a disturbance in the Force can cause much greater damage than some petty disturbance in the ionosphere ;-)

  • OK.... (Score:3, Funny)

    by SpurtyBurger ( 1400111 ) on Tuesday December 23, 2008 @10:51AM (#26211963)
    who moved it?

  • Definition? (Score:2, Interesting)

    by Count_Froggy ( 781541 )
    The distance to the edge of an atmospheric layer varies by definition, season, orbit, solar radiation conditions, and probably a variety of other conditions. If the edge measured was at 220km instead of 420km, is there agreement on the definition (as a start)? 220 km converts to about 137 miles. 420km converts to about 261 miles. (sorry, I'm in the US, I think in non-metric units.) The US requirement for astronaut wings is 50 miles. Since none of the people in orbit since 1960 (except for moonshots) we
  • Somehow this never screwed up NASA...I would think the distance you have to travel to clear earth's atmosphere would have been an important thing for space flight. Anyone want to shed some light on this? Is it just that when space is concerned 200km is pretty small?
  • Has it changed http://en.wikipedia.org/wiki/Karman_line [wikipedia.org]

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