NASA image of Earth from space

An astrophysicist discovers the line between Earth’s atmosphere and space is closer than we thought

Contributed by
Jul 26, 2018

The edge of space has just edged in a littler closer to us earthlings. Well, okay, it hasn’t actually moved, it just may be closer than we had previously thought. 

In a new paper written by astrophysicist Jonathan McDowell, the line where Earth’s atmosphere ends and outer space begins may be closer than formerly calculated, according to a report by Live Science. About 12 miles closer, in fact. 

After “considering orbital and suborbital trajectories used by space vehicles,” McDowell writes that, after investigating “the inner edge of outer space from historical, physical and technological viewpoints,” he proposes that the boundary between the Earth's atmosphere and outer space is more likely to be 80 kilometers (roughly 50 miles) above sea level, rather than the currently popular 100 kilometers (roughly 62 miles). This line is known as the Karman line.  

McDowell concludes in his research paper that “the effective Karman line is close to (within 10 km of) 80 km independent of solar and atmospheric conditions, rather than the currently popular 100 km value; and that historical orbital data for actual artificial satellites confirms that orbiting objects can survive multiple perigees at altitudes around 80–90 km.”

He added: “On the basis of these physical, technological and historical arguments, I therefore suggest that a value of 80 km is a more suitable choice to use as the canonical lower ‘edge of space’ in circumstances where such a dividing line between atmosphere and space is desired.”

Now what does this mean in the grand scheme of things? Not much, according to McDowell. It won't change the way rockets are launched or any other physical interactions with space. However, it could potentially raise some political and territorial issues. For example, the airspace above a given country is generally considered part of that country. So, if space is defined as beginning at 62 miles above sea level, and the U.S. flies a satellite lower than over a country without that country’s OK, that could be interpreted as an act of military aggression. Gulp.

This is one of the many reasons why it’s unlikely that McDowell's new 50-mile line will become a legally-accepted border anytime soon. But on the upside, you’ve just become 12 miles closer to the stars than you were before you read this article.

(Via Live Science)

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