Planet Mercury the Hottest Planet? More Mercury Facts | Almanac.com

Is Mercury the Hottest Planet? And More Odd Facts.

Photo Credit
Manu Arregi Biziola/NASA

And what color is planet Mercury?

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The innermost planet is odd in so many ways, it’s hard to find aspects that aren’t strange. Planet Mercury is not much bigger than our own Moon! Named for the swift messenger of the Gods, this planet speeds nearest to the Sun. But is it the hottest planet? See what you know about Mercury.

10 Facts about Planet Mercury

  1. Mercury’s orbit may be nearest around the Sun, so you’d think it was also the hottest planet. Nope! It’s the second hottest planet. The “hottest of them all” title is claimed by our neighbor Venus, thanks to its dense atmosphere. Learn more about Venus, planet of paradox.
  2. Mercury is a planet of extremes. During the day, Mercury’s temperatures reach highs of 801°F (427°C) thanks to its nearness to the Sun. This is hot enough to melt lead! At night, temperatures are as low as -280°F (-180°C). This is because the planet does not have an atmosphere to trap heat.
  3. Mercury takes only 88 Earth days to zip around the Sun, so it’s the fastest of the planets. However, it takes a full 59 days to rotate one round on its own axis; that’s a very long work day! 
  4. Mercury has the most lopsided, out-of-round orbit of any planet. Thanks to tugs from Jupiter, of all unlikely villains, the Mercury orbit wildly changes shape. In the future its orbit may stretch all the way out and let it collide with Venus, destroying both worlds in the next five billion years.
  5. Mercury alters its brightness more than any other planet, varying a thousandfold. And while Venus looks brightest when it’s near to us, Mercury shines most brightly when it’s farthest from us—like right now.
  6. Often we think of Mercury as red. However, Mercury is dark gray and covered with rock and dust. Venus is bright white. Mars is a rust-orange color. Mercury has been a cooled molten rock for billions of years, and the only planet in our Solar System which is bare rock.
  7. Planet Mercury is named after the Roman god Mercury because he is the “messenger” god who can fly, wearing a winged hat and sandles.
  8. Mercury does have the most craters, which may sound strange. However, this is because there is no weather to erode away the craters as you will find on other planets. Mercury has no volcanoes, no tectonic activity, and no storms or wind or rain. There’s very little atmosphere at all. 
  9. As Mercury spins, it has no axial tilt. At its polar depressions, the sun is always below the horizon, so these regions are packed with ice. They offer winter sports on a world badly needing it.
  10. And even that isn’t the end of Mercurian strangeness. It has a region called The Weird Terrain. I’m not making that up. It’s located at the precise opposite point on Mercury from its most famous impact crater, the enormous Caloris Basin. Apparently, debris or else shock waves from that impacting meteor traveled around the planet and collided in mid-air at the antipodal pointto wreak havoc there.
Photo Credit: P.M. Heden
Photo Credit: P.M. Hedén

How to See Mercury After Sunset

You do need an unobstructed horizon to see Mercury, our solar system’s innermost planet. 

The time is important. Twilight deepens as dusk progresses, which makes finding Mercury easier, and yet it’s sinking lower all the while. You want the right balance. 40 minutes after sunset is perfect.

See our sunset times for your location.

Occupying the faint constellation Aries all this month, it’s the ONLY star low down in the direction of sunset. If have binoculars, use them.

Go out the first clear night and look very low in the west. See that strange orange planet for yourself.