Why doesn't the vacuum of space suck away Earth's atmosphere?

It's often said that "nature abhores a vacuum." If that's true, then why doesn't the vacuum of space suck away our atmosphere? Tune in as Marshall Brain explains the science behind vacuums in this HowStuffWorks podcast.

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Episode Transcript

Speaker 1 (00:00):
Welcome to brain Stuff from how Stuff Works dot com
where smart Happens. I am Marshall Brain with today's question.
If Nature of Horrors a vacuum, then why doesn't the
vacuum of space sec away all of Earth's atmosphere? From
our daily experience with nature, it does seem like Nature
of Horrors a vacuum. If you create a vacuum inside

(00:22):
a container here on Earth, Nature will fill the container
with air very quickly if you puncture that container. On
the other hand, we know that outer space is a
giant vacuum. Outer Space is infinitely larger than Earth, so
ninety nine point nine percent of our universe is a vacuum.
Based on this, it might be better to say that

(00:44):
nature loves a vacuum, so why doesn't the vacuum of
outer space suck away our atmosphere. Say you're standing on
Earth holding a glass bottle. If you attach the bottle
to a vacuum pump, pump out all the air, and
then seal the bottle, the bottle contains a vacuum. If
you put a hole in the bottle, air rushes in.
But the reason it rushes in is because of the

(01:06):
air pressure around the bottle. Standing on the ground, we
are standing in an ocean of air that rises many
miles above us. The air molecules stack up on each
other and they create the pressure of fourteen point seven
pounds per square inches sea level. The higher you rise
in the atmosphere, the shorter the stack of molecules, so

(01:27):
the lower the pressure at sea level. It's the weight
of all of the molecules stacked above the bottle, fourteen
point seven pounds of them in every square inch that
forces the molecule into the punctured vacuum. If you were
to travel in a rocket to the edge of the atmosphere,
you would find that there is no air pressure. Instead,

(01:48):
individual air molecules are zipping around in the vacuum of space.
The molecules can zip anywhere they like, but they tend
to zip towards the Earth because the Earth's gravity acts
on them, just could acts on anything else with mass.
The reason the vacuum of space doesn't attract the molecules
is because there is no suction to the vacuum space.

(02:09):
There's no air pressure forcing things into that vacuum. All
there is in space is molecules traveling through the vacuum.
You can see that there's no danger of the vacuum
sucking our atmosphere away, But it turns out that there
is another force that could strip away the atmosphere. That
force is called solar wind. Fortunately, the atmosphere is protected

(02:32):
from the solar wind by the Earth's magnetic field. Do
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