Question

Is it possible to make a perfect vacuum?

Asked by: Dan Klingensmith

Answer

Practically, it is impossible to make a perfect vacuum. A perfect vacuum is defined as a region in space without any particles.

The problem is that to maintain a vacuum in a region you have to shield it from the environment. It is not difficult to make a container that would prevent atoms from entering the region.

The first problem is that the container itself will radiate photons (which in turn can create electron positron pairs in the vacuum) if it is not kept at a temperature of 0°K. Note that a perfect vacuum has by definition a temperature of 0°K. reaching 0 °K is practically impossible.

The second problem is that there are weakly interacting particles that could enter the region. No matter how thick the walls of the container are, there is always a finite probability that, say, a neutrino would enter the region.

Answered by: Saibal Mitra, M.S., Physics Grad Student, UVA Amsterdam

Search

Loading






Science Quote

'Strange is our situation here upon the earth. Each of us comes for a short visit, not knowing why, yet sometimes seeming to divine a purpose.'

Albert Einstein
(1879-1955)
Science Sidebar | Science Education Articles
10 Ways to Keep Your Kids Interested In Science

Young children are natural scientists: they ask questions, pick up sticks and bugs outside, and are curious about the world around them. But as they get a bit older, many kids gradually lose their interest in science. They might see it as just another task at school, something that doesn't apply to their lives. Of course nothing could be further from the truth, so here are ten ways you can remind your kids that science is everywhere. Most of these are fun for adults, too! Continue reading ...

Top Selling

Here are our physics & astronomy bestsellers:
Magnetic Levitator - Classic
12 inch Galileo Thermometer
Cricket, Locust, Beetle and Crab
Solar Radiometer
Weather Station 4M Kit
3D Magnetic Field Tube
Clean Water Science 4M Kit
Revolving Multi-Color Fiberoptic Light
Periodic Table of Elements Poster - Laminated
Solar Science 4M Kit

Sponsors

USC University of Southern California Dornsife College Physics and Astronomy Department McMaster University Physics and Astronomy Department