Topic: vacuum

vacuum theoretically, space without matter in it. A perfect vacuum has never been obtained; the best man-made vacuums contain less than 100,000 gas molecules per cc, compared to about 30 billion billion (30×10 18 ) molecules for air at sea level. The most nearly perfect vacuum exists in intergalactic space, where it is estimated that on the average there is less than one molecule per cubic meter. In ancient times the belief that "nature abhors a vacuum" was held widely and persisted without serious question until the late 16th and early 17th cent., when the experimental observations... Read more