Astronomy Closer Look: Mercury

Discussion in 'Astronomy' started by JcMinJapan, Sep 5, 2004.

  1. JcMinJapan

    JcMinJapan Premium Member

    I love astronomy and have tons of data on the planets. I have studied the planets quite extensively due to this love and have tons of notes taken from many places. I thought that I would share some of them on each of the 9 planets. I will start with Mercury and move my way back. If there is anything I have left out,. gotten wrong or you have some cool facts, please add them in here.

    I hope this helps some one. It is great to go back through all my notes and get a refresher for this. Please add facts if you have any more. any new information is certainly welcome! :)

    Mercury is the closest planet to the Sun.
    Mercury is the 8th largest planet in the solar system.
    Mercury day is about 3 Earth Months and it takes it takes 88 days to orbit the Sun.
    Mercury is the only body in the solar system known to have an orbital/rotational resonance with a ratio other than 1:1
    Mercury is 57,910,000 km (0.38 AU) from Sun
    The diameter is 4,880 km
    It is the 2nd smallest planet behind Pluto.
    The mass of Mercury is fairly hefty compared to its size at 3.30e23 kg. Only the Earth is more dense in our solar system. So, due to it`s size and the density, it is guesstimated that Mercury has a very large Iron core.
    The temperature reaches a hefty 427 degrees Celsius during the day and a very cool -183 degrees Celsius during the night on the side of the planet not facing the sun. Only the temperature on Venus is hotter.
    the surface is heavily cratered and also has no plate tech-tonics. It is very similar to the moon.
    Mercury does have a very thin atmosphere made of helium and sodium, but it is so hot, that the atoms that make it up are being thrown into outer space rather quickly. Thus, it is considered the only planet whose atmosphere is being constantly replenished.
    Mercury's magnetic field is rather small it only about 1% of Earth's field in comparison.
    There are no satellites (moons) that orbit the planet.

    Mercury's orbit is very strange when is comes to comparing orbits of other planets in our solar system. At perihelion it is a mere 46 million km from the Sun but at aphelion it is 70 million. In the early 19th Century, many astronomers tried to explain its orbital bath, but, it did not match with physics at the time. Einstein's General Theory of Relativity was able to account for the obit, which led it to being recognized early as a correct theory.

    Cool Facts:

    The planet Mercury was named after the Roman God of Commerce and Thievery, now, it is guessed that it was named after Mercury because of how fast it travels across the sky at night.

    From what I can find, the Sumerians had documented the planet about 3000 years ago, but have not been able to find anything prior to that. But, of course that would be very hard to do as the Sumerians were very very ancient.

    Mariner 10 flew by Mercury in 1974 & 1975. We have only been able to map about 45% of the surface. "Messenger" was launched in 2004 and will orbit Mercury starting in 2011.

    Ice on Mercury? Well, possibly at the North Pole... Radar has shown that there could be pockets of ice in some shadows of very large craters, so they are not melted by the sun. But, this area is not of the portion that has been mapped yet.

    A Double Sunrise! Yes, it is true.... sometimes the rotation speed of the planet falls below the orbit speed of Mercury around the Sun, so the Sun will rise then then set after only a few hours, then it will rise again as normal.

    For very detailed information and great photos of Mercury visit NASA