In our everyday encounters with nature, it appears that vacuums are indeed disliked. For instance, if you create a vacuum within a container on Earth, air will rapidly fill it once given the opportunity, such as by making a hole in the container.
Conversely, outer space is an immense vacuum, infinitely vast compared to Earth, meaning nearly the entire universe exists as a vacuum. This might suggest that "nature adores a vacuum!" So, why doesn't space's vacuum draw our atmosphere away?
Imagine holding a glass bottle on Earth. If you use a vacuum pump to remove all the air from the bottle and then seal it, a vacuum is created inside. Puncturing the bottle causes air to rush in due to the surrounding air pressure. On the ground, we are submerged in an ocean of air extending miles above us. Air molecules stack up, creating a pressure of 14.7 pounds per square inch (psi) at sea level. As you ascend in the atmosphere, the stack of molecules shortens, reducing the pressure.
At sea level, the weight of all the molecules stacked above the bottle (14.7 pounds per square inch) forces air into any punctured vacuum.
Traveling in a rocket to the atmosphere's edge, you'd discover the absence of air pressure. Instead, individual air molecules move freely in the vacuum of space. While these molecules can travel anywhere, they are drawn toward Earth due to its gravity, which affects them just as it does any other mass. The vacuum of space doesn't pull these molecules because there's no suction or air pressure to force them into the vacuum. Space is simply a void through which molecules travel.
While the vacuum poses no threat of sucking away our atmosphere, another force, known as the solar wind, could potentially strip it away. Thankfully, Earth's magnetic field shields the atmosphere from the solar wind's effects.
Explore more with these helpful links:
- The Solar Wind
- NASA plans studies of Martian atmosphere - January 1999
- Terraforming Mars
- How Terraforming Mars Will Work
- How Space Shuttles Work
- Would a balloon filled with vacuum instead of helium float?
- How do satellites orbit the earth?
- Sea level - 14.7 psi
- 10,000 feet - 10.2 psi
- 20,000 feet - 6.4 psi
- 30,000 feet - 4.3 psi
- 40,000 feet - 2.7 psi
- 50,000 feet - 1.6 psi
