back to article NASA's IBEX to sniff interstellar boundary

NASA's Interstellar Boundary Explorer, aka IBEX, will on 19 October lift off from Kwajalein Atoll in the Marshall Islands on a mission to probe the interstellar boundary beyond our heliosphere's termination shock1 - a region where "the hot solar wind slams into the cold expanse of space", as NASA nicely puts it. From an altitude …


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deep space dot

Am i missing the point on this one, but are NASA sending a 2ft. by 3ft. 0.0000001 mega-pixel camera into deepest darkest space? Not exactly a Hubble replacement, is it. Guys, save the cash for the christmas party, i confidently predict the cam's will send back a blackish dot,

something like this -> . <-

Paris Hilton

Nasa standards problems ...

Since they can mix up metric and imperial measurements is it a good idea to ask them to try and use another universal standard such as Reg units?

Wouldn't be safer for everyone to use a more easily identified international standard such as Lego (tm) bricks, which can be used for length, volume, weight and area.

With some imagination I'm sure that Lego (tm) bricks could be used for temperature and force as well.

Lets just hope that people don't start confusing Lego (tm) and Duplo (tm) ... sigh..


hmm no Lego (tm) icon, Ok lets go for PH instead 'cos she'd probably (tm)'d as well by now.


Voyager 1 ?

Now, don't get me wrong. I'm all for sending hi-tec gadgetry to explore the vast expanses of the universe...... however,,,,,, we all know that superior intelligences will get hold of Voyager 1 and will send it back as Vger to communicate with the Maker, i.e. the Human Race (it's true cos I saw it in Star Trek - The Movie). What would any self-respecting super intelligence think of a species that sent a STOP sign equipped with a 1 megapixel camera floating into the void - not a lot - we have our intergalatic street cred to think of !?!


Space Corps. Directive #196156-A

Any probe caught sniffing the heliosphere's termination shock will be discharged without trial.

Anonymous Coward

How do they do that?

> heliopause, where the wind's particles are no longer energetic enough to advance against rival particles from other stars.

When the number of particles is two or three per cubic meter, I am curious how they all know just where to be to collide head-on with each other.

Thumb Down


"1The termination shock is the point in the heliosphere where the solar wind is slowed to subsonic speeds (relative to the emitting star) by interaction with the interstellar medium."

Am I missing something here? What exactly IS the speed of sound IN A VACUUM?

Or, perhaps the question should be...

what is the speed of "FAIL"?


@AC re: subsonic

Space is not entirely a vacuum, only a medium well approximation of one. Deep space is full of matter (mostly thinly distributed hydrogen with traces of Helium and a few other elements).

In astronomical terms, the speed of sound is defined as that speed at which a stream of particles (e.g. the solar wind) is so fast it cannot simply displace matter it encounters on its way, but impacts fast enough to create a shock wave (e.g., the heliosphere's termination shock). That is the point in the heliosphere at which the solar wind is just strong enough to completely displace the interstellar medium. Outside the termination shock, interstellar medium and solar wind can intermingle, because the solar wind is no longer fast enough to completely displace the interstellar medium. Inside the termination shock, we don't get much interstellar medium, because the solar wind is still supersonic.

Hope this helped...

Silver badge

Cosmic Rays

"The interstellar boundary regions are critical because they shield us from the vast majority of dangerous galactic cosmic rays, which otherwise would penetrate into Earth's orbit and make human spaceflight much more dangerous."

Which is a GOOD thing.

Because it means that any human being crossing the heliopause will be subject to rapid vapourisation by a relentless barrage of pi-mesons.

Which means that the human vermin are confined by their weak biology to their own solar system.

This of course makes your Lizard Alliance overlords very happy, not to mention rather relieved.

Mine's the one with "I, for one..." printed on the back, ta.

Gold badge


Thanks for that. I'd wondered about that one from earlier, voyager-related articles mentioning the termination shock. I'd never got round to looking it up myself though.

Have an oakleaf and cluster to go with that boffin icon.

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