Mercury is nearest planet to the Sun. Its also the smallest planet in the Solar System. The degree of axis of tilt of Mercury is just 2. It is so close to the Sun that it is difficult to see it from the ground. This explains why some early astronomers never saw the planet. When seen from the Earth Mercury is never far from the Sun in the sky. Because of the glare of the Sun, it can only be seen in twilight or in the dawn. That is why it is called as the morning or evening star.
Mercury was first recorded by Timocharis in 265 BC. Other early astronomers who studied Mercury include Zupus(1639 BC) who studied its orbit. The perihelion of Mercury's orbit precesses around the Sun at an excess of 43 arcseconds per century; a phenomenon that was explained in the 20th century by Albert Einstein's General Theory of Relativity. Mercury is bright when viewed from Earth, ranging from −2.3 to 5.7 in apparent magnitude, but is not easily seen as its greatest angular separation from the Sun is only 28.3°. Since Mercury is normally lost in the glare of the Sun, unless there is a solar eclipse it can be viewed from Earth's Northern Hemisphere only in morning or evening twilight, while its extreme elongations occur in Declinations south of the celestial equator, such that it can be seen at favorable apparitions from moderate latitudes in the Southern Hemisphere in a fully dark sky.
Mercury was first recorded by Timocharis in 265 BC. Other early astronomers who studied Mercury include Zupus(1639 BC) who studied its orbit. The perihelion of Mercury's orbit precesses around the Sun at an excess of 43 arcseconds per century; a phenomenon that was explained in the 20th century by Albert Einstein's General Theory of Relativity. Mercury is bright when viewed from Earth, ranging from −2.3 to 5.7 in apparent magnitude, but is not easily seen as its greatest angular separation from the Sun is only 28.3°. Since Mercury is normally lost in the glare of the Sun, unless there is a solar eclipse it can be viewed from Earth's Northern Hemisphere only in morning or evening twilight, while its extreme elongations occur in Declinations south of the celestial equator, such that it can be seen at favorable apparitions from moderate latitudes in the Southern Hemisphere in a fully dark sky.
- Distance from sun: 58 million miles
aphelion - 70 million miles
perihelion - 48 million miles - Diameter: 4878 km
- Year: 88 Earth days
- Day: 59 Earth days
- Moons: 0
- Crust: 300 km
- Mantle: 700 km
- Core: <1800 km
- Surface Area: 7.483 km2
- Volume: 6.083 X 10^10 km
- Mass: 3.3021 X 10^23 kg
- Mean Density: 5.427 g /cm^3
- Escape Velocity: 4.25 km/s
- Atmosphere: No
Due to absence of atmosphere, there is a high range of temperature. In the morning, the temperatures soar upto 400 °C but at night, the temperatures drop to about -200 °C
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