The Sun
2003 UB313
Mercury - Closest planet to the Sun
Mercury Image Courtesy
Mercury is only slightly larger than our moon. The two look quite similar as neither has an atmosphere, and both are freckled with meteorite craters. The earth would look much the same on the outside, but the earth is covered in water and has an atmosphere that causes meteorites to burn up on entry. Mercury's pitted surface shows many large craters, the largest of which is The Caloris Basin which is about 1,300km/800mi wide ( larger than Texas ). The effects of the asteroid that caused the crater can be seen on the opposite side of mercury, and this serves to show how catastrophic this collision really was.

In fact, if you look closely at the photo of mercury ( right ) then you might have confused it for a picture of our moon. Only someone who has studied the two would know the difference at a glance. If you study the facts for each you will see that both are very different. One major difference is in how they orbit. Mercury travels solely around the Sun, and the moon travels around the Earth which is traveling around the Sun. The moon has a tidal stationary orbit - meaning that only one side of the moon faces the Earth at any given point in time, but mercury rotates as it orbits the Sun causing all sides to raise and lower in temperature accordingly. If mercury had a tidal stationary orbit around the sun, as was previously thought, this would leave one side very, very cold, and the other would be extremely hot. Temperature readings from mercury have proven that it does, in fact, rotate as it revolves around the Sun.

Mercury's sky is constantly black as there is no atmosphere to cause light to bounce around and spread out, and it goes from very hot in direct sunlight to very cold in the shade or dark night. These temperature changes mean that a super space suit would have to be developed in order for astronauts to land on the surface of Mercury and walk around. The suit would have to cool them in the intense heat, warm them in the severe cold, and shield them from the massive amounts of radiation coming from the Sun which appears to be three times as big in Mercury's sky. The Sun is so close that the electronics on the passing satellites must also be shielded from the intense heat and radiation.

Mercury's rotation is flat against it's orbit around the Sun, and this leaves the low lying areas around the poles in constant darkness. Long ago covered by dust these regions may very well contain ice, and the different spectrums of light captured in the satellite photos confirm this suspicion, but more surveillance is required in order to know for sure that the regions do, in fact, contain ice. The possibility of ice is just another amazing fact about the closest planet to the Sun.

An interesting fact about Mercury is that its orbit is not a perfect circle. Its elliptical, or egg shaped, orbit takes it closer to the Sun at one point, out to a greater distance, and back in again. This elliptical orbit, in conjunction with the rotation, causes the Sun to appear to rise and then set for a short time only to rise again to complete the day. At sun-set the Sun sets, comes back up, and sets again for the duration of the night. This would be a weird effect indeed if it were to be happening on Earth, but we all would have had to get used to it by now if that were the case here on Earth. Just think we'd have phrases like "The first Sun-rise bird gets the worm," and "first Sun-set and first Sun-rise makes a man healthy, wealthy, and wise!" Life would be just a little bit different on Mercury! Consider having to stay up for 58.64 earth days just to see the Sun rise twice, and then set twice before a long night and morning finally came again.

Discuss Mercury in our forums: Mercury


Mercury Statistics Table:
    Things to keep in mind:
  • 1 A.U. is the distance from the Earth to the Sun, or 93 million miles ( 149.6 million km )
  • Planets have elliptical orbits, and distances given are the average distance from the sun.
  • Measurements given in earth terms. If read "days" or "years," earth days and earth years are implied
Date of Discovery Known by the Ancients
Average Distance from the Sun 57,909,175 km
35,983,095 miles
0.38709893 A.U.
Equatorial Radius 2,439.7 km
1,516.0 miles
Equatorial Circumference 15,329.1 km
9,525.1 miles
Density 5.427 g/cm3
Surface Area 74,800,000 km2
28,900,000 mi2
Gravity 3.7 m/s2
12.1 ft/s2
Rotation Period (Length of Day) 58.646 days
1407.5 hours
Orbit Period (Length of Year) 0.241 years
87.97 days
Orbital Velocity (avg) 172,341 km/h
107,088 mph
Orbital Circumference 356,000,000 km
221,000,000 miles
Min/Max Surface Temperature -173/427 C
-279/801 F
100/700 K

Article written by IceCreamTruck and was compiled after extensive reading and study. This article is formatted to include information that isn't obvious from looking at most facts and figures sheets. Exact figures about the planet courtesy of JPL NASA and have been shortened to include only the most useful information. Please visit NASA's website for further detailed information on this planet NASA Mercury Pages

Home Page |  Webmasters |  Under 13 Terms |  About Us |  Contact Us
All material contained in this website, in whole or in part, is the property of
All rights are reserved, and you may not put it to use without the expressed consent of the administrator
Sign up for PayPal and start accepting credit card payments instantly.