A vacuum is a volume that is ideally devoid of matter. However there is no such thing as a perfect vacuum in nature. A better working definition would be any volume with less gaseous pressure than regular atmospheric pressure. In most cases natural vacuums are referred to as partial vacuums. A vacuum can be natural or artificially created. The applications of vacuums have led to important breakthroughs in science and technology ranging from preservation and sterilization and to early computing and light bulbs. Whether you know it or not vacuums are more common and closer than most people think.
A vacuum is a volume with extremely low matter density. Space is a perfect example because of its near perfect vacuum. In fact interstellar space often only has a few atoms of hydrogen per square meter. This partial vacuum is so perfect that the speed of light in space is much faster than on Earth. This also means that space has almost zero friction. This allows stars, planets, and galaxies to move solely under the influence of gravity. This same gravitational force also helps stars keeps their atmosphere. An interest aspect of space is that one of the reason why the vacuum is only partial is that atmosphere gradually blend into space. For example Earth does not have an absolute boundary for its atmosphere. It simply starts to thin out until at the ionosphere the pressure of the solar wind is greater than Earth’s atmospheric pressure.
Vacuums are not just found in space. Mankind has also made use of them in various technologies. First there are research applications. Vacuums have been used in various fields of science from biology to aerospace. There are several reasons for using vacuums in research. First it is a unique state that no life form can survive. This allows for easy sterilization of a research area. Also the environment of vacuum prevents chemical corrosion since ambient gases like oxygen that might react to sensitive chemicals are absent. This property was used in incandescent light bulb to protect the filament.
Vacuums are even being researched for new types of energy such as zero point energy. However much of this is still theory. In space exploration the effects of vacuums on humans is also being explored on the International Space Station. In the end we are still learning more about vacuums and their applications in science and technology.
We have written many articles about vacuum for Universe Today. Here’s an article about why space is black, and here’s an article about how the Earth protects us from space.
If you’d like more info on vacuum, check out this article about outer space vacuum. Also, check out an article about how human body reacts to vacuum outer space.
We’ve also recorded an entire episode of Astronomy Cast all about Spacesuits. Listen here, Episode 121: Spacesuits.
Source:
http://www.gresham.ac.uk/lectures-and-events/astronomy-much-ado-about-nothing
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