What if Mars is Earth's Moon

Astronomy: what if Jupiter were our moon?

Moonrise without a moon - but with planets. The artist Ron Miller realized this scenario with the backdrop of a California desert road

The magnitudes in space are beyond human imagination. For example, how far are the 150 million kilometers that lie between the earth and the sun? What are the dimensions of the planet Jupiter, into which our earth fits 1321 times? How tangible is the number of 100 billion stars that belong at least to the Milky Way, which in turn is only one of at least 100 billion galaxies in the universe?

The illustrator Ron Miller, who has long been picturing alien planets and cosmic phenomena with scientific meticulousness, tries to make the unimaginable imaginable. For example, by regrouping the solar system and asking a simple question: How would we see the other planets if they were only 384,000 kilometers from Earth, as far as our moon on average?

For the answers Miller calculated the proportions between the moon and the planets and transferred the results to the night sky: If you divide the celestial circle on the horizon between west and east into 180 degrees, the moon covers an average of just half a degree. Mars, at the same distance, seemed to us about twice as big.

Venus, on the other hand, would cover two degrees, so it would appear four times as large as the earth's satellite (and, incidentally, would be the same size as the earth when viewed from the moon). And Jupiter would be so huge that it would take up much of the visible night sky. "We'd all be a little more humble if Jupiter were constantly present in the sky to this extent," said Miller. Miller always chose the same place to look at his planetary constellations: a road in Death Valley in California - and the perspective of a nocturnal driver.

As realistic as Miller's pictures seem, he had to make compromises on some points. In truth, Jupiter would appear much brighter to us because its bright clouds reflect more sunlight than the dusty moon. And of course Jupiter or Saturn would never orbit the earth - but make our planet their satellite. Jupiter alone has 2.5 times the mass of all the planets in the solar system combined. Miller's art can look back on a long tradition in the USA. 71 years ago, in its issue of May 29, 1944, the magazine "Life" printed a graphic by the American Chesley Bonestell: "Saturn, seen from its moon Titan". It was one of the first scientific space illustrations.

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