Planets
Mercury
Because Mercury is so close to the sun, it is hard to directly observe from Earth except during twilight. Mercury makes an appearance indirectly, however, 13 times each century. Earth observers can watch Mercury pass across the face of the sun, an event called a transit. These rare transits fall within several days of May 8 and November 10.
Scientists used to think that the same side of Mercury always faces the sun, but in 1965 astronomers discovered that the planet rotates three times during every two orbits. Mercury speeds around the sun every 88 days, traveling through space at nearly 31 miles (50 kilometers) per second faster than any other planet. The length of one Mercury day (sidereal rotation) is equal to 58.646 Earth days.
Diameter :
4,878km (3,032 miles) at its equator, which is
about two-fifths of Earth's diameter.
Orbit : 57,910,000 km (0.38 AU) from Sun. Orbiting the Sun once every 88 days.
Average Distance : About 58 million km (36 million miles)
Time to Rotate: 58.6 days
Mass: 3.30e23 kg (5.5% of Earth's)
Mercury goes round the Sun
so quickly, the planet was called after the messenger of the Roman
Gods. The messenger Mercury, or Hermes as the Greeks knew him, is
usually shown as having wings on his helmet or on his sandals. Mercury’s sunny side has a temperature
rising to 400° Celsius or 750° Fahrenheit. Compare this to a warm
summer’s day in London, when the temperature might be 80° Fahrenheit or
26° Celsius. Mercury’s dark side, however, is very cold indeed, with the temperature going down to -200° Celsius or -328° Fahrenheit.
Because Mercury is so close to the sun, it is hard to directly observe from Earth except during twilight. Mercury makes an appearance indirectly, however, 13 times each century. Earth observers can watch Mercury pass across the face of the sun, an event called a transit. These rare transits fall within several days of May 8 and November 10.
Scientists used to think that the same side of Mercury always faces the sun, but in 1965 astronomers discovered that the planet rotates three times during every two orbits. Mercury speeds around the sun every 88 days, traveling through space at nearly 31 miles (50 kilometers) per second faster than any other planet. The length of one Mercury day (sidereal rotation) is equal to 58.646 Earth days.
Mercury is dry, extremely hot and almost airless. Planet Mercury is too small
for its gravity to retain any significant atmosphere over long periods of time.
The weak atmosphere contains hydrogen, helium, oxygen, sodium, calcium and
potassium.
Due
to the heat of the planet, the very thin atmosphere is blasted off its surface
by the solar wind and quickly escapes into space. Mercury's atmosphere is
constantly being replenished.
Mercury does not have enough atmosphere to slow down meteoroids and burn them up
by friction. The sun's rays are approximately seven times as strong on Mercury
as they are on the Earth. The sun also appears about 2 1/2 times as large in
Mercury's sky as in the Earth's.
The surface of Mercury consists of cratered terrain and smooth plains and many
deep craters similar to those on the moon. The craters formed when meteors or
small comets crashed into the planet. The largest known crater is Caloris Basin,
with a diameter of 1300 km
The first photographs of the surface of
Mercury were taken by the USA Space Agency, NASA. The Mariner 10
spacecraft passed close to the planet in 1974 and 1975 and took very
clear photographs.NASA’s latest mission to Mercury is
called Messenger. The Messenger spacecraft entered Mercury’s orbit in
March 2011 and is sending back new pictures of the planet. Messenger is
now moving with Mercury round the Sun.
Amazing Facts About Mercury :
We can see two sun rise and sun set in mercury . mercury has no moons
Mercury has been known since at least the time of the Sumerians (3rd millennium
BC). It was sometimes given separate names for its apparitions as a
morning star and as an evening star. Greek astronomers knew, however,
that the two names referred to the same body.
Heraclitus even believed that Mercury and Venus orbit the Sun, not the Earth.
Mercury has been known since at least the time of the Sumerians (3rd millennium
BC). It was sometimes given separate names for its apparitions as a
morning star and as an evening star. Greek astronomers knew, however,
that the two names referred to the same body.
Heraclitus even believed that Mercury and Venus orbit the Sun, not the Earth
Mercury has been known since at least the time of the Sumerians (3rd millennium
BC). It was sometimes given separate names for its apparitions as a
morning star and as an evening star. Greek astronomers knew, however,
that the two names referred to the same body.
Heraclitus even believed that Mercury and Venus orbit the Sun, not the Earth.
Mercury has been known since at least the time of the Sumerians (3rd millennium
BC). It was sometimes given separate names for its apparitions as a
morning star and as an evening star. Greek astronomers knew, however,
that the two names referred to the same body.
Heraclitus even believed that Mercury and Venus orbit the Sun, not the Earth.
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