Mercury is the smallest planet in the solar system and is the closest planet to the sun. Though it may, at first, appear to be just a small ball of rock next to the sun, Mercury is as mysterious a planet as all the rest. Here are a few interesting facts about Mercury that make it a unique planet.
Mercury is Small and Fast
Despite Mercury’s diminutive size and distance from the Earth (48 million miles), it is sometimes visible to the naked eye. According to Dr. Maria Zuber, Director of Geophysics and Planetary Science at MIT, when Mercury is visible it can be seen after sunset low in the western sky. It can also be viewed before sunrise, low in the eastern sky.
Mercury is similar to the moon in both size and appearance. Mercury’s diameter is 3,031 miles (4,878 km) just 859 miles more than the moon. Like the moon, Mercury is pocked from meteor impacts and has mountains, craters and valleys.
Mercury zips around the sun faster than any other planet at 30 miles per second. A year, or one full orbit around the sun, occurs every 88 Earth days. A day on Mercury, however, lasts longer than its year. One day, or one full rotation on its axis, happens once every 176 days on Earth.
What Distinguishes Mercury From the Other Planets?
Mercury has an elliptical orbit. At its closest point it is only 28.6 million miles away from the sun. It travels to almost 44 million miles at its furthest point from the sun. This distance doesn’t help it much against the blazing heat of the sun. Daytime temperatures on Mercury can reach as high as 850°F and as low as -275°F at night. Because of its close proximity, the sun would appear two and a half times as large as it appears from Earth.
Mercury does not have a functioning atmosphere. Though gases like hydrogen, oxygen, helium and sodium have been detected close to Mercury’s surface, the planet is unable to maintain an atmosphere. Because Mercury lacks an atmosphere, meteors that might have been small enough to be burned up in Earth’s atmosphere are able to impact the planet. This gives Mercury its heavily pocked appearance. The lack of an atmosphere also means that Mercury’s sky is always black and Venus and Earth would appear as blazing stars from the surface.
Mercury, like its neighbor Venus, has neither moons nor rings. These are the only two planets in the solar system without orbiting moons.
Recent Mercury Discoveries
Mercury may have water on its surface in the form of ice. The ice is at the North Pole where temperatures are low enough to keep the water in ice form and prevent it from evaporating. Scientists suspect that the ice could have come from an impacting meteor.
Recent photos of Mercury have revealed that the planet has had volcanic activity. Scientist had often debated whether there could be any volcanic activity on Mercury but with this new evidence there can be no doubt. However, it is difficult to determine if the volcano is still active or if there are other sites where volcanism may occur.
Mercury has a magnetic field that protects the surface of the planet from violent solar winds and radiation. Magnetic fields radiate out from planets, interact with the sun’s radiation and protect the planet. Scientists recently discovered evidence of Mercury’s magnetic field and found it to be fairly similar to Earth’s.
Mercury is a fascinating planet that continues to surprise and mystify scientists. Though it is doubtful that humans could ever travel to Mercury, as it is so close to the sun, scientists are finding means to watch it from afar. Who knows what new discoveries will be made in the future as scientists continue to study this tiny planet next to the sun.
References:
“Mercury Magnetosphere Fends Off The Solar Wind.” Space Daily. 2008.
Zuber, Maria T. "Mercury." World Book Online Reference Center. 2004.
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