Space Is Just a Little Bit Closer Than Expected

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."

Comments

Wow

[IceCreamGuy]

skyisfalling tag has never been so accurate!

Re:Wow

[JustOK]

yet, were is the proof that its not the earth that is rising?

Re:Wow

[aaron alderman]

What about nothingofvaluewaslost?
Could even throw in a correlationisnotcausation or maybe vaporware.

Re:Wow

[Anonymous Coward]

Earth is growing! :o

Oh god, i don't want to headbutt space!
I'm building an underground city, if you want to live, follow me!

interesting

[Technopaladin]

Thats a pretty wide margin of error.

Things in the Ionosphere can be closer then they appear.

Re:interesting

[aaron alderman]

1) Send humans into space
2) Redefine the boundary between space and atmosphere
3) ...
4) Profit!!

So...

[Anonymous Coward]

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

how could we not have already known this?

[Anonymous Coward]

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

Re:how could we not have already known this?

[Quantumstate]

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

Obligatory

[Revotron]

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

below 30MHz

[FudRucker]

HF propagation is effected too...

Re:below 30MHz

[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...

Erosion of the ionosphere?

[BadAnalogyGuy]

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:Erosion of the ionosphere?

[David Gerard]

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, 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. They basically had to build an entire car frame and put the original plastic shell around it.

Re:Erosion of the ionosphere?

[Reziac]

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 evidence that we don't understand the atmosphere well enough to purposefully fuck with it (as some stop-global-warming schemes propose to do).

She's gone from suck to blow!

[millisa]

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

Re:She's gone from suck to blow!

[VJ42]

It's 1234

Re:She's gone from suck to blow!

[Amazing Quantum Man]

What a coincidence! I have that same combination on my luggage!

Re:Commun ications

[Anonymous Coward]

Nonsense. There is no way this will affect communi

[NO CARRIER]

Global Warming Explanation!!!

[sac13]

Now we know why the Earth is warming. We've just got less atmosphere to hold all the heat.

WTF???

[Nom du Keyboard]

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???

[FailedTheTuringTest]

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..."

For a given value of ionosphere, and of Space

[DynaSoar]

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/

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".

Re:For a given value of ionosphere, and of Space

[Doctor_Marc]

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

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

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

Re:Even More Obligatory

[Sebilrazen]

Wow, 420 just took on a whole new significance!

You looking to get hooked up?

I got the new Ionic Chronic gets you so high, you'll feel like you're in outer space.

GPS

[Detritus]

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

[digitig]

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

[bangzilla]

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

[greg_barton]

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. :)

Re:Charades

[Anonymous Coward]

Your parties sound like a lot of fun. I think I'll stick to snorting blow off of hookers asses.

Re:Charades

[kaizendojo]

Thanks Mr. President. We'll leave the light on for you.

Atmospheric depth and temperature

[RobotWisdom]

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.

OK....

[SpurtyBurger]

who moved it?

Real title.

[Thanshin]

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"

Definition?

[Count_Froggy]

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) went higher than the upper number, where they all in orbit within the ionosphere, according to the claimed 'old' definition? Unlikely.