The small and rocky planet Mercury is the closest planet to the Sun; it speeds around the Sun in a wildly elliptical (non-circular) orbit that takes it as close as 47 million km and as far as 70 million km from the Sun. Mercury completes a trip around the Sun every 88 days, speeding through space at nearly 50 km per second, faster than any other planet. Because it is so close to the Sun, temperatures on its surface can reach a scorching 467 degrees Celsius. But because the planet has hardly any atmosphere to keep it warm, nighttime temperatures can drop to a frigid -183 degrees Celsius. Because Mercury is so close to the Sun, it is hard to see from Earth except during twilight. Until 1965, scientists thought that the same side of Mercury always faced the Sun. Then, astronomers discovered that Mercury completes three rotations for every two orbits around the Sun. If you wanted to stay up for a Mercury day, you'd have to stay up for 176 Earth days. Like our Moon, Mercury has almost no atmosphere. What little atmosphere exists is made up of atoms blasted off its surface by the solar wind and has less than a million-billionths the pressure of Earth's atmosphere at sea level. It is composed chiefly of oxygen, sodium, and helium. Because of Mercury's extreme surface temperature, these atoms quickly escape into space and are constantly replenished. With no atmosphere to protect the surface, there has been no erosion from wind or water, and meteorites do not burn up due to friction as they do in other planetary atmospheres. Mercury's surface very much resembles Earth's Moon, scarred by thousands of impact craters resulting from collisions with meteors. While there are areas of smooth terrain, there are also cliffs, some soaring up to a mile high, formed by ancient impacts. The Caloris Basin, one of the largest features on Mercury, is about 1,300 km in diameter. It was the result of an asteroid impact on the planet's surface early in the solar system's history, the probable cause of the strange surfaces on the opposite side of the planet. Over the next half-billion years, Mercury actually shrank in radius from 2 to 4 km as the planet cooled from its formation. The outer crust, called the lithosphere, was compressed and grew strong enough to prevent the planet's magma from reaching the surface, effectively ending the planet's period of geologic activity. Evidence of Mercury's active past is seen in the smooth plains in the Caloris basin. Mariner 10's first image of Mercury. Mercury is the second smallest planet in the solar system, larger only than Pluto, the most distant planet in our solar system. If Earth were the size of a baseball, Mercury would be the size of a golf ball. Viewed from Mercury, the Sun would look almost three times as large as it does from Earth. Mercury is the second densest body in the solar system after Earth, with an interior made of a large iron core with a radius of 1,800 to 1,900 km, nearly 75 percent of the planet's diameter and nearly the size of Earth's Moon. Mercury's outer shell, comparable to Earth's outer shell (called the mantle) is only 500 to 600 km thick. Only one spacecraft has ever visited Mercury: Mariner 10 in 1974-75. Mariner 10's discovery that Mercury has a very weak magnetic field, similar to but weaker than Earth's, was a major surprise. In 1991, astronomers using radar observations showed that Mercury may have water ice at its north and south poles. The ice exists inside deep craters. The floors of these craters remain in perpetual shadow, so the Sun cannot melt the ice. Here is why Mercury cannot have any seasons........This is for the Boys who say i am wrong

Before understanding why there are no seasons on Mercury, we should know why seasons occur on Earth. The answer is obvious. Earth rotates around Sun in an elliptical and and eccentric orbit. That causes it to be too close to Sun during some period and too far from the Sun during another period. And when we are close to Sun, it is Summer, and when we are farther away from Sun, we feel cold. Other seasons like Autumn, Mansoon are caused because of the change in inclination of the Earth as it rotates around Sun. Approximately, 18 deg swing about the axis of Earth happens as it moves from one end of the orbit to the other end. These things do not happen on Mercury. Moreover, it is very close to Sun (so only summer season found, Ha Ha Ha!!!). Hence no seasons on Mercury.

Actually, I think the real reason is that mercury is so small, that it doesn't have an atmosphere at all. Without an atmosphere, there's no such thing as "wet season", "dry season", let alone spring, summer, fall, winter. This is because our atmosphere allows water in suspension (%rel. humidity) which in turn forms clouds, that drift into different pressure areas, and temperature areas, and finally rain. The cold not only makes it rain but also snow. No snow on mercury, sorry!

The Earth has seasons because it is on a 23 degree tilt away from/towards the sun. Mercury has a 2 degree inclination, so it would have seasons, only hardly noticeable.

First, I agree with DDatts in that we need to understand why Earth has seasons. Unfortunately, most people don't understand why this is. It is a common misconception that it is because of the elliptical nature of Earth's orbit that causes the season. This is not the case. The difference in distance from the Sun over the course of a year is not sufficient to cause the seasons. Additionally, this would not explain why the souther hemisphere's seasons are opposite of the northern hemisphere's. What causes the seasons is the fact that Earth's axis is tilted 23.5 degrees from perpendicular to Earth's plain of revolution. Earth's axis points toward the same point in the sky all year round. This means that its orientation to the Sun changes as Earth orbits the Sun. So, at some times of the year, the North Pole is tilted toward the Sun and at other times of the year, it is pointed away. At those times that the north pole is pointed toward the sun, the northern hemisphere gets more direct sunlight and longer days. The more direct sunlight more strongly heats Earth's surface. The longer days mean more time to heat the surface. These two factors combine to cause warmer temperatures. When the north pole is tilted away from the Sun, then the northern hemisphere gets less direct sunlight and shorter days. This leads to cooler weather. This also explains why the southern hemisphere has it season opposite of the northern hemisphere. When the north pole is tilted toward the Sun, then the southern hemisphere is tilted away from the sun and vice versa. Now, why doesn't Mercury have seasons? It's because Mercury's axis is only tilted 0.1 degrees off perpendicular, to the plane of it's orbit. In other words, there is no significant till to its axis. So, other than rising and setting as a result of its rotation, there is no significant change the way the light comes into Mercury's surface. Therefore, there are no seasons.

The titlt is different that earth and it may change.

Seasons are caused by the tilt of the axis relative to the planet's orbital motion. Mercury's axis is directly perpendicular to its motion, so it has no seasons. Some parts of Mercury experience cyclical temperature variations. Side Note - Mercury/Mercurius is Latin - messenger of the gods. Greeks named the planet for Hermes - messenger with winged feet.

not to mention that mercury couldnt have seasons regardless of the tilt because of its distance to the sun... its basically on fire all the time

It's really hot, it spins really slow and it's years are really quick. The planet completes a trip around the Sun every 88 days speeding through space at nearly 50 km per second, faster than any other planet. Because it is so close to the Sun, temperatures on its surface can reach a scorching 467 degrees Celsius. But because the planet has hardly any atmosphere to keep it warm, nighttime temperatures can drop to a frigid -183 degrees Celsius. http://space.about.com/od/factsaboutmercury/a/mercuryinfo.htm The length of a day on Mercury is 176 earth days You can't have a season if your days are longer than your years. That just defies logic.

actually the earth is moving thru space in a straight line and the sun and universe are rotating around it...mathematically speaking, ha.