Vacuum

A perfect vacuum is defined as a space without any matter. However, experts believe a perfect vacuum state is impossible to achieve because of the quantum uncertainty principle. Instead, scientists measure degrees of vacuum by how few particles are found in a particular area and the amount of atmospheric pressure exerted in the area. Atmospheric pressure is a measurement of the strength of the pressure in an area when compared to the average amount of pressure commonly exerted on Earth.

According to these measurements, deep space is the closest example of a perfect vacuum found in nature. In practical terms, a vacuum is an area of space with so little matter that its atmospheric pressure is much less than what is normally experienced on Earth. The study of vacuums has proven very important in physics, quantum physics, engineering, and astronomy. Vacuums are also used in the creation of many modern conveniences.

The Study of Vacuums

The original concept of a vacuum, a space occupied by nothing at all, is far from new. The ancient Greeks debated the possibility of the existence of a vacuum, but had trouble reconciling its existence with how they believed the world functioned. From their point of view, the concept that an area could both exist and be nothing was ridiculous. The idea was not commonly revisited until the philosopher Abu Muhammad Al-Farabi conducted experiments on vacuums using plungers in the late ninth and early tenth centuries. He agreed that vacuums were impossible, primarily because he believed air expanded to fill all empty space.

Researchers began experimenting with vacuums and atmospheric pressure during the seventeenth century, though most failed to realize that vacuums were behind the phenomena they observed. Scientists studied airtight tubes filled with mercury and gas. They used a pump to remove gas (a form of matter) from the container. Removing the gaseous matter created a small vacuum. Because of the reduced pressure in the vacuum, the mercury rose higher in the tube.

Blaise Pascal was the first scientist to interpret these experiments correctly. He conducted more experiments that proved the mercury rose because of the reduced atmospheric pressure in the vacuum. Still, many of the most prominent scientists of his time scorned his ideas. Even the famous philosopher René Descartes considered the idea that empty spaces could exist between atoms laughable. The pascal, a common unit of measurement for atmospheric pressure, was later named after Blaise Pascal in recognition of his contribution to science.

After Pascal's theories were dismissed, scientists and philosophers composed the theory of ether (also called æther) to account for perceived gaps in space. It proposed that an invisible gas called ether filled all of outer space, allowing light and energy to move through it. However, this theory was comparatively short-lived. Einstein published his theory of relativity, which proposed that many of the grand functions of the universe were carried out through gravity. While Einstein's theories allowed for the existence of ether, they did not require it. Instead, they showed that the universe does not need to be consistently full of matter to function.

Paul Dirac and Werner Heisenberg, early proponents of quantum physics, also helped bring the scientific community's concepts of vacuums to their modern form. According to quantum physics, a true vacuum can never exist. While deep space is probably as close as possible to a true vacuum, the occasional atoms will still be found there. According to Heisenberg's famous uncertainty principle, the location of any particle is never truly certain. Because of this principle, temporary particles called virtual particles (most often virtual electrons and virtual positrons) will occasionally spring into existence out of nothingness and quickly disappear. This process is called vacuum fluctuation. Due to vacuum fluctuation, a space can never stay truly empty of particles.

Modern quantum mechanics defines vacuums as the state of having the lowest possible energy. Thus, degrees vacuums are measured in terms of how much atmospheric pressure is exerted in a given area. As a state gets closer to a perfect vacuum, less atmospheric pressure is exerted. As a state gets further from a perfect vacuum, more atmospheric pressure is exerted.

Why Study Vacuums?

Vacuums contribute to countless areas of modern life. As their name suggests, vacuum cleaners of all kinds use a pump to remove gas from a chamber, which causes air and debris to rush in and fill the partial vacuum created. In a vacuum cleaner, a filter traps and stores the debris. Water pumps utilize vacuums in a similar manner. Electric lights require a vacuum to function properly, and the semiconductors common to electronic devices are created using vacuums. Even many aircraft parts are designed to be vacuum powered. These parts continue to function properly during an electrical failure, improving the pilot's ability to safely land the aircraft.

Additionally, the study of vacuums leads to interesting observations about our universe. Studying how light moves in a vacuum, including what causes it to slow down, accelerate, or bend, is incredibly important for observing and mapping the known universe. Some scientists even think a better understanding of how quantum physics function in a vacuum, specifically the theoretical energy inherent in vacuums called zero point energy, will lead to a clearer understanding of why the universe is expanding.

Because most of outer space is an extreme vacuum, the study of vacuums is essential for any projects that involve humans or objects leaving Earth. Detailed knowledge of how physics and chemical reactions function in a vacuum is essential for navigating outer space. Experiments on Earth, along with data from accidents in space, showed scientists that humans exposed to extreme vacuums like those found in outer space lose consciousness in less than fifteen seconds and suffer fatal complications in just minutes. Studying how matter acts in a vacuum allows scientists and engineers to build spacecraft and space suits. These complex systems allow humans to survive in extreme vacuums for extended periods without harm.

Bibliography

Boi, Luciano. "A Scientific and Philosophical Concept, from Electrodynamics to String Theory and the Geometry of the Microscopic World." The Quantum Vacuum. JHU Press, 2011. Print. Available online at https://books.google.com/books?id=rAEVOLae‗FoC&pg=PA3&lpg=PA3&dq=introduction+to+vacuum+space+-technology&source=bl&ots=OvgOcQkiBN&sig=i4tOHv6WKEwSXmZVDMXBqxLZTlY&hl=en&sa=X&ei=IHuYVPvoBtOHsQTIioDoCw&ved=0CEAQ6AEwBDgo#v=onepage&q&f=false

Gosline, Anna. "Survival in Space Unprotected Is Possible—Briefly." Scientific American. Scientific American, Inc. 14 Feb. 2008. Web. 23 Dec. 2014. http://www.scientificamerican.com/article/survival-in-space-unprotected-possible/

Matthews, Robert. "Nothing Like a Vacuum." Calphysics.org. Calphysics Institute. Web. 23 Dec. 2014. http://www.calphysics.org/haisch/matthews.html

"More About Vacuum Pumps." ThomasNet.com. Thomas Publishing Company. Web. 23 Dec. 2014. http://www.thomasnet.com/about/vacuum-pumps-65021602.html

"Supernova Study Might Change How Speed of Light in Vacuum is Measured." ZMEScience.com. ZME Media. 25 Jun. 2014. Web. 23 Dec. 2014. http://www.zmescience.com/space/supernova-speed-of-light-change053456/