Top 10 Weirdest Facts About the Planet Mercury

Greek form, Hermes, god of thieves, communication and a bunch of other things. As a planet, Mercury is kinda peculiar, to say the least, so here's another list about a planet, and boy might these facts surprise you.
The Top Ten
1 Mercury has extreme temperature swings

If you assumed Mercury is the hottest planet in our solar system, you're actually wrong. Mercury is a little weird, in terms of its temperature range. Yeah, it is a hot planet, for the most part, but its surface can still be relatively cold. This is because there's no atmosphere to trap heat. Without, temperature during the day can reach about 840 degrees Fahrenheit, but at night, the temperature can get as low as around 275 degrees Fahrenheit. That fluctuation makes a temperature swing of more than just hundreds of degrees Fahrenheit. This planet has the largest temperature swing in our entire solar system.

Great list, not the standard Wikipedia entries here... The temperature on Mercury's dark side does dip to a low of around minus 300 degrees Fahrenheit. As mentioned else where on the list, Mercury's exosphere (atmosphere) is virtually non-existent, it's essentially a vacuum.

Back in early 2014 I was passionate about planets and I refused to believe that Mercury isn't always hot and that it gets cold at night even after seeing the fact multiple times. So one time I had to do a research project in class in February 2014 and I had to put that Mercury is freezing at night but I refused to do it.

2 A day on Mercury is longer than a year on Mercury

On earth, we're accustomed to the 24 hour day and 365 day year that we get on our planet. A day on Mercury is actually longer than a year. One day is defined by the amount of time it takes a planet to rotate on its axis, so on Mercury, one day is equal to 176 days on earth. A year is defined by how long it takes a planet to orbit the sun once, and on Mercury, a year is about 88 days on earth. So, as strange as it may be, a day on Mercury is twice as long as a year on Mercury. If you're still confused, about how that works, to be honest, I am, too, but let's just keep it simple and say that it's all about science.

...On Mercury, I wouldn't be 17, I would be nearly 68.

3 It's thought that surviving a hit from an asteroid created Mercury's peculiar orbit

Roughly four billion years ago, an asteroid about sixty miles wide struck Mercury quite hard, and as a result, it made a gigantic crater about nine hundred and sixty miles wide. We call this impact crater the Caloris Basin, and you could fit all of Texas inside it. This asteroid hitting Mercury may have played a hand in the planet's peculiar rotation. Mercury is tidally locked with the Sun in a 3:2 spin orbit resonance. In other words, it rotates on its axis exactly three times for every two times it completes an orbit around the Sun.

4 Mercury's core makes about three fourths of the planet

Mercury's core makes about seventy percent of the planet's radius. This gigantic core has more iron in it than any other planet's core in the entire solar system. Scientists aren't all on the same page, regarding how Mercury's core got so much iron, but lots think it has to do with solar magnetism. The Sun's magnetic field controlled certain materials, including iron, which were just kind of "there" when our solar system was new. Given how close Mercury is to the sun, when the planets came into existence, Mercury took in more iron than Venus, Earth, Mars, the gas giants, or Pluto. It's really all about gravity, distance from the sun, and the small amount of mass that Mercury is.

The core is so strange that I heard some videos that states the planet will continue to become smaller.

5 Mercury doesn't have a moon

Most planets do have moons. Heck, even Pluto has two. But Mercury doesn't have a moon because it's too close to the sun. If Mercury had a moon, it would probably either crash into Mercury, and destroy both the planet and its moon, or the moon would perhaps go into orbit around the Sun and eventually get pulled into it. Mercury doesn't have a gravitational pull strong enough to hold anything in orbit around it. Especially given how tiny Mercury is, and how vast the sun is. Physics go against Mercury having a moon.

6 Mercury has ice on it

To be honest, in contrast with other facts on this list, this one isn't too weird. But it's weird nonetheless that the planet closest to the sun indeed has ice on it. As Mercury orbits the sun, some pockets of large craters don't receive direct sunlight, and they get cold. The cold areas have been cold for billions of years, enabling ice to be kept in its solid state, even though Mercury is the closest planet to the sun. As for how it got there, there are multiple potential answers. One is that the ice might have been brought to Mercury by comets coming from the outermost areas of the solar system, around where Pluto is.

Okay that is pretty unusual I'm surprised that there would be enough ice from comets to even notice it.

Now this is a very weird fact about Mercury.

7 You'd weigh about a third of your weight on Mercury

How does this work, you ask? We calculate weight on other planets by
multiplying your mass by the gravitational pull on the surface of the planet, so for Mercury, you'd have the equation 3.285 × 10^23 kilograms, to determine your weight, and that's just around one third of your weight on earth. So a person who weighs 154 pounds on earth weighs 58.08 pounds on Mercury, or someone who weighs 222 pounds on earth weighs 83.73 pounds on Mercury.

Now that I think about it it's a little surprising the gravity is so low given that the planet has so much iron (which I thought would be denser than most rock).

8 Mercury isn't the hottest planet

The hottest planet is actually Venus, mostly due to Mercury not having an atmosphere.

9 Mercury has very little atmosphere

For the same reasons that it has no moon, Mercury has no atmosphere. Or if it does, it's a very weak one. For starters, Mercury is so close to the sun that a strong atmosphere would be burned up by the sun. It is also too small to have a strong gravitational pull on just about anything, including an atmosphere, therefore the atmosphere would be pulled off of the planet. Mercury also orbits the sun so quickly that an atmosphere would be blown off of it. And the speed at which Mercury rotates on its axis would also be at such a pace that an atmosphere would be stripped off of the planet, like a shirt.

It's extremely thin atmosphere combined with its slow rotation (relative to its orbit) explains why its temperature varies. Same with Earth's moon. It's atmosphere contains traces of hydrogen, sodium & oxygen (of which isn't enough for us to breathe or live our lives with). Yet it's only 0.5 nanopascals (nPA) at sea level.

So, This is the reason why Venus and not Mercury is the hottest planet. Atmosphere makes Venus much hotter than Mercury.

10 Mercury has the most craters out of any planet in our solar system

Unlike other planets that heal themselves through processes in nature, the surface of Mercury is scarred with craters. These craters were made by various close calls with asteroids and comets. Any crater larger that have at least 250 kilometers in diameter is dubbed as a Basin. The Caloris Basin, mentioned earlier on this list, is the largest impact crater on Mercury. It covers around 1,550 kilometers. But there are at least 413 other craters on Mercury

The Contenders
11 Mercury has a tail

When I say a tail, I mean one from usually a comet. Magnetic tails are made when intense radiation pressure from solar winds push on, in this case, Mercury's magnetic fields. These tails are made on the side of the planet that is facing away from the sun. On Mercury, magnetic storms in its tail are much larger and more fast-paced than magnetic storms on Earth.

12 Mercury was mistakenly believed to be different objects in the night sky

It was thought that mercury are just the two different object. The two objects are The Morning Star and The Evening Star

I believe the ancient Greeks thought it was two different stars, given how quickly it moves around the sun.

13 Mercury is the second densest planet in the solar system

To be honest, just read what NuclearMetalPlant said. There's not much of a better way to explain it.

14 Mercury is the closest planet to the sun
15 Mercury is the smallest planet in the Solar System

It's actually not much larger than earth's moon, although I personally still consider Pluto a planet despite it being classified as a dwarf planet in I believe 2007.

A fact that we all learned in kindergarten is weird? How did I not know that?!

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