# Eli5: Could you create a vacuum stronger than space, and take a sample of the contents of space?

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Eli5: Could you create a vacuum stronger than space, and take a sample of the contents of space?

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No, a vacuum is the absence of anything it’s impossible to less than pretty close to nothing.

Depends which space you mean.

Average density of space in the Solar System? Yes, we’ve managed to beat that.

Average density of intergalactic space? No, not even close.

And take a sample of the contents of space? Yes, that’s how we know what the density is.

Simply, space is close enough to perfect vacuum to not make a difference.

Better answer: vacuums work because particles push against each other. Think about people packed into a big room all trying to run around blindly as much as they can, bumping and pushing and shoving each other. When you open the doors they will start pushing each other out (because they’re pushing each other everywhere) and bouncing off of each other and probably make a mess. But you’re not pulling them out that door, you’re just giving them new empty space to move into.

But if you only have one or two people running around in your massive room, you can open the door and it doesn’t matter – they just won’t bump into each other enough for either of them to end up running out the door by random chance any time soon.

[This page](https://hypertextbook.com/facts/2000/DaWeiCai.shtml) quotes sources that range from 0.06-1000 atoms in a cubic centimetre. That’s basically nothing. Imagine two people running around an entire city, shoving each other when they met, and waiting for one to get shoved out of your doorway. Imagine ten people running blindly around a *country*. The atoms in free space just aren’t close enough together to make any kind of pressure to push into a vacuum, so it wouldn’t help you collect a sample of space any more than, say, swinging a plastic bag around out there would.

You seem to have a fundamental misunderstanding of what a vacuum is. This is ok! Let me explain.

A vacuum is created by, if you will, the presence of nothing. No atoms, at least. Perhaps some energy and radiation but no matter. No mass. No thing.

Things move into a vacuum because of other forces acting upon them. On the surface of the earth, a vacuum seems to “suck” bit that is quite the opposite of that is happening. The void of nothingness that has been created has tons and tons of air molecules and atoms and whatnots all stacked up on top of each other all the way out until gravity can’t hold them any more. That’s heavy! So, the atmosphere actually pushes on the outside of things, trying to fill that void. So, when you make a vacuum with your mouth to use a straw, the atmosphere is actually pushing the drink into your mouth by the sheer weight of all that air around you.

But why doesn’t the air crush you? Well, that’s why our skin will bulge and flesh redden when introduced to a vacuum. We were born under pressure. Evolved in it. Introduce it to a vacuum and our insides, like the atmosphere and with assistance *from* the atmosphere, try to rush in. One part being squeezed by the atmosphere and it trying to get you into that empty space, one part our bodies having a lot of dissolved gases and things that like to expand under a vacuum.

But that is a perfect vacuum. The “suction” created by, say, a vacuum cleaner is most likely to give you a bad red mark from blood vessels bursting and blood trying to pool into the vacuum… But nothing *too* serious.and even then, only if you left it on there for a good while. The power they draw would be harmless for a moment.

Even in a (near) perfect vacuum, a human can survive for a few moments with only some edema (fluid pooling in tissues it shouldn’t pool in) and some temporary sense loss (sight and hearing, I believe.)

I would have to look it up for accuracy, but in short, an astronaut was once accidentally exposed to a near perfect vacuum in a training facility and survived. Bonus content to look up.

It really depends on where in space we are.

In our solar system there are about 10-100 molecules or atoms per cm^(3), so you can think of the atoms being a few millimeters apart. Between galaxies we are talking about 1 particle in 1m^(3). On earth vacuum down to about 300 particles per m^(3) has been achieved.

So yes, we could make a vacuum stronger than some parts of space and in theory we could use the vacuum to suck up particles from space. However, we would only catch very few molecules with this method unless our vaccum chamber is huge and we could as well transport instruments to space which analyse their surroundings directly.