# What is the vacuum of space **URL:** \ **Category:** Factual Questions\ **Created:** [December 29, 2002, 5:53am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476 "2002-12-29T05:53:59Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Rebel307](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rebel307](https://boards.straightdope.com/u/Rebel307)\ **Post date:** [December 29, 2002, 5:53am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/1 "2002-12-29T05:53:59Z")
I hear about the vacuum of space quite often but have never actually seen any documentation of just how much vacuum it would pull. I would like it if someone could answer my question of how much of a vacuum it really is. ---
**Author:** ![trader\_of\_shots](https://avatars.discourse-cdn.com/v4/letter/t/aeb1de/32.png) [@trader\_of\_shots](https://boards.straightdope.com/u/trader_of_shots)\ **Post date:** [December 29, 2002, 5:58am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/2 "2002-12-29T05:58:30Z")
I have always taken it to mean, The vacume of space is any location that can hold mass but currently does not. As apposed to Nothing, which can never hold anything because it does not exist. I thought it was an attempted to differentiate between Space and Nothing. But i am a bit of newby on this stuff… soz. Wait for a pro to turn up. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [December 29, 2002, 6:10am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/3 "2002-12-29T06:10:05Z")
Vacuum is not necessarily all that empty [Space-Time: The Final Frontier](http://www.astro.lsa.umich.edu/users/hughes/ucourses/120f96/inf3.html) > [@](#): > > True, the cosmos consists overwhelmingly of vacuum. Yet vacuum itself is proving not to be empty at all. It is much more complex than most people would guess. “But surely,” you might ask, “if you take a container and remove everything from inside it - every atom, every photon - there will be nothing left?” Not by a long shot. Since the 1920s physicists have recognized that on a microscopic scale, the vacuum itself is alive with activity. Moreover, this network of activity may extend right down to include the very structure of space-time itself. The fine structure of the vacuum may ultimately hold the keys to some of the deepest questions facing physics - from why elementary particles have the properties they do, to the cause of the Big Bang and the likelihood of other universes outside our own. [Zero Pont Energy of the Vacuum of Space](http://www.helical-structures.org/Chapters/Chapter5.pdf) ---
**Author:** ![trader\_of\_shots](https://avatars.discourse-cdn.com/v4/letter/t/aeb1de/32.png) [@trader\_of\_shots](https://boards.straightdope.com/u/trader_of_shots)\ **Post date:** [December 29, 2002, 6:14am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/4 "2002-12-29T06:14:19Z")
Well of course it isn’t empty - all the gas particles being stretched out etc. But how close was my explanation Astro or was i talking out my hat again ? ---
**Author:** ![Rebel307](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rebel307](https://boards.straightdope.com/u/Rebel307)\ **Post date:** [December 29, 2002, 6:18am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/5 "2002-12-29T06:18:50Z")
I mean in space like the moon, or in orbit around the earth. I know about objects and how they occupy space but I mean as in strapping yourself to a giant missle and launching yourself toward the sky ( I have been wanting to say something like that for a long time. Why would anyone wanna fly, expecally when feul is expencive and if you run out,your %$#@ed ) ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [December 29, 2002, 6:26am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/6 "2002-12-29T06:26:49Z")
Rebel, vacuum isn’t a “thing” it’s absence of something like dark is an absence of light. Your vacuum cleaner doesn’t suck dirt any more than a flashlight sucks up dark. It uses a fan to evacuate air from a bag so the higher atmosphere pressure pushes air and dirt into it. You can only measure vacuum relative to a pressure so what you’re really measuring is the pressure of your reference. If I have two boxes full of “Absolute space vacuum\*” there will be no measurable difference between them. If one box has sea level earth atmosphere I’ll measure a vacuum of 14.7lb per square inch… or a pressure of 14.7psi, it just depends on which side you’re standing on. If you come from a different planet your frame of reference for “normal” pressure may be completely different. \*For the sake of argument one molecule per cubic meter. ---
**Author:** ![Rebel307](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rebel307](https://boards.straightdope.com/u/Rebel307)\ **Post date:** [December 29, 2002, 6:47am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/7 "2002-12-29T06:47:10Z")
so more or less a space craft have to hold an earth atmosphere of about 14.7 psi. I have always wondered that. basically a basketball with say,50psi sent into space , the pressure inside the ball would stay the same and if it could handle en extra 14.7 psi it wouldnt explode\>? ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [December 29, 2002, 7:43am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/8 "2002-12-29T07:43:05Z")
> [@](#): > > \*Originally posted by Rebel307 \* > \*\*so more or less a space craft have to hold an earth atmosphere of about 14.7 psi. I have always wondered that. basically a basketball with say,50psi sent into space , the pressure inside the ball would stay the same and if it could handle en extra 14.7 psi it wouldnt explode\>? \*\* Actually, humans can function down to about 5 PSI, though they won’t be running any marathons. The spacesuits used by shuttle crews can be as low as 4.3 PSI, pure oxygen. [Source](http://www.bway.net/~rjnoonan/humans_in_space/air.html). The same is true of conventional aircraft. A 747 at 30,000 feet has an internal cabin pressure considerably lower than sea level. If they could somehow keep it at around 14.7 PSI, passengers wouldn’t suffer any of the ear-popping or other effects. This is impractical, though. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [December 29, 2002, 8:12am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/9 "2002-12-29T08:12:19Z")
> [@](#): > > \*Originally posted by Rebel307 \* > **basically a basketball with say,50psi sent into space , the pressure inside the ball would stay the same and if it could handle en extra 14.7 psi it wouldnt explode\>?** That’s right. Well, strictly speaking, the extra pressure across the skin might cause the ball to expand slightly, causing the pressure to drop slightly. But it should be a small effect. If it were a rigid aluminum can, the pressure would stay exactly the same. ---
**Author:** ![Rebel307](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rebel307](https://boards.straightdope.com/u/Rebel307)\ **Post date:** [December 30, 2002, 4:14am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/10 "2002-12-30T04:14:01Z")
Thats what I wanted to know thank you all \<\<\<\<\< PS What does IHMO mean?\>\>\>\>\>\> ---
**Author:** ![clayton\_e](https://avatars.discourse-cdn.com/v4/letter/c/c57346/32.png) [@clayton\_e](https://boards.straightdope.com/u/clayton_e)\ **Post date:** [December 30, 2002, 5:47am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/11 "2002-12-30T05:47:14Z")
In My Humble Opinion it means… oh. ---
**Author:** ![Mockingbird](https://avatars.discourse-cdn.com/v4/letter/m/c68b51/32.png) [@Mockingbird](https://boards.straightdope.com/u/Mockingbird)\ **Post date:** [December 30, 2002, 5:49am UTC](https://boards.straightdope.com/t/what-is-the-vacuum-of-space/145476/12 "2002-12-30T05:49:25Z")
The vacuum of space is the same vacuum anywhere: an Electrolux.