Mars vs. Earth for Dummies

Mars-Earth comparison

A lot of our staffers here at the Antisocial Network are, to be honest, nerds. Not the kind who call themselves "software engineers" because programmer sounds too simple. No, they're scientists. And although the current presidential administration seems hellbent on making certain that the citizenry is kept ignorant of scientific principles, they're not gonna give in. That's why we keep harping on scientific literacy, and keep shaming freelancers faking their way to a small fee. People like self-described "business writer" Eric Bank, who claims a B. S. in biology but sure wasn't using any of it when he wrote "How Big Is Mars Compared to Earth?"¹ for eHow.

In this case, it's not a matter of scientific inaccuracy... well, in a way it is. You see, as Bank trolled the internet for simplistic information to share, and to pad out the answer from "the diameter of Mars is a little more than 50% that of Earth," he had to do some math. And he did it wrong.

The factoids Bank reproduced from the spiffy NASA website about Mars he cites are simple. According to Eric, "Earth has 10 times the mass of Mars, over six times the volume and is 1.41 times as dense." Ummm.... that's not what the reference says, but perhaps the numbers were too small for Bank to read. According to a less glitzy NASA website, the mass of Mars is 10.7% of Earth's mass and its density is 71.3% of Earth's density (the reciprocal of which isn't 1.41, it's 1.403). Do the math: with a mass of 0.107 Earths and density of 0.713 Earths, the comparison of the volume of Mars to that of Earth must be

1 / (0.713 / 0.107) 

or almost exactly 15%. The glitzier NASA website bears that factoid out -- the volumes of Mars and Earth are in the ratio of 39 / 260, or 0.15. Yet Bank reduces this to "over six times the volume"; a 10% error. One wonders whether clients of our Dumbass of the Day and his financial advisor business would accept a ten-percent error...

¹ The original has been deleted by Leaf Group, but can still be accessed using the Wayback machine at archive.org. Its URL was   ehow.com/about_4568768_how-big-mars-compared-earth.html

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