Out of this World Pressures

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities and you. In this blog we’ll be discussing pressure outside of our blue planet.

Out of this World Pressures

The earth’s average atmospheric pressure is 1 bar (101.3kPa, 29.92 mm Hg or 14.69 psi). Temperature and altitude are among the factors that cause variations. At a specific location, the air pressure can vary about 10%. Leave this planet, where we have the weight of a life-producing atmosphere of oxygen and nitrogen exerting pressure on us and the situation is quite different.

In outer space, the pressure is 1.322 × 10-11 Pa – essentially zero, since there is very little air and hardly any water.

Our nearest neighbor, the moon, has a surface pressure at night of 3 x 10-15 bar (or 3 x10-10 Pa). In contrast, Mars has a layer of gases surrounding it composed mostly of carbon dioxide. As a result, the atmospheric pressure on the Martian surface averages average  750 Pa (0.109 psi) or about 1/100 of the Earth’s. At any given location on Mars, the air pressure can vary by as much as 50%.

Earth’s pressure variations at a given location seem small compared to these other locations. Measuring earth’s pressure variations is also quite easy and commonly performed with a 100 kPa absolute pressure sensor.

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The size difference between Earth and Mars is minor compared to the atmospheric pressure difference. Image courtesy of NASA.

What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Han Mai, Senior Marketing Specialist, All Sensors Corporation (hmai@allsensors.com)