is the closest planet to the sun in the solar system. Here are some scientific
and interesting facts about this planet.
Mercury was named for the fleet-footed messenger of the gods in Roman mythology
– the equivalent of the Greek’s Hermes.
Mercury is the first planet in distance from the Sun in the
solar system. It is the smallest of the 8 planets.
This planet is the smallest of the rocky or terrestrial planets. The others are
Venus, Earth, and Mars.
Mercury is the only rocky planet other than Earth to have a global
magnetic field, which is about 1% as strong as Earth’s.
Like Venus, Mercury has no moons of its own.
Although it is the nearest planet to the Sun, it is only the second hottest
planet. Venus is the hottest.
Mercury circles the Sun every 88 Earth days at an average distance of 58
million km and takes 59 days to turns on its axis.
Mercury’s diameter is 4,879 km, about 40% the diameter of Earth or
about 40% wider than the Moon.
Mercury’s volume and mass are about one-eighteenth that of Earth.
Mercury’s mean density, 5.4 g/cm³, is nearly as great as that of Earth and is
higher than that of any of the other planets.
The force of gravity on the planet’s surface is about 1/3 of that on Earth’s
surface or about twice the surface gravity on the Moon and about the same as
the surface gravity on Mars.
Jupiter’s moon Ganymede and Saturn’s moon Titan are larger than Mercury but are
much less dense.
Mercury orbits the Sun every 87.97 Earth days at an average
distance of approximately 58 million km.
Mercury’s orbit is highly elliptical and ranges from 46 million km at its
nearest point to the Sun (perihelion) to 69.8 million km at its farthest point
As a result, sunlight is over 2.3 times stronger at perihelion than at
At a single orbit, Mercury receives as much as 11 times the intensity of
sunlight that Earth does to a minimum of about 4.5 times.
Mercury’s orbital velocity is also about 46 percent faster at perihelion than
at aphelion. The planet’s orbit is tilted 7 degrees to the plane in which Earth
orbits around the Sun.
When viewed from North Pole. Mercury turns counterclockwise (west to east)
like Earth and most other planets.
Earth’s axis is tilted 23.5° while Mercury’s axis is almost perfectly vertical.
Because its axis is vertical, like Venus, Mercury does not have seasons.
Mercury rotates only once every 58.65 days, 2/3 of its period of revolution
around the Sun.
A complete solar day on Mercury lasts 175.84 Earth days, or two of Mercury’s
years, and a night and a day at the equator each last one Mercurian year or
87.97 Earth days.
preserves a record of a violent early period when asteroids, comets, and other
debris bombarded the newly formed planets.
The craters on Mercury are shallower than those on the Moon.
The largest geological feature on Mercury is the Caloris Basin. It is the
result of a massive ancient impact.
Mercury’s surface is crisscrossed by long escarpments or cliffs.
Mercury is a poor reflector of sunlight because its surface
consists of dark, dry soil called regolith created by micrometeorite impacts
over billions of years.
The planet’s albedo, or the amount of sunlight it reflects, is only about 12
percent, about the same as our Moon.
28.) Surface temperatures on
Mercury can be as hot as 650°C.
Mercury’s side facing the Sun gets very hot—up to 450°C—while the side facing
away quickly cools to frigid temperatures, -183°.
The floors of craters at the north and south poles receive very little sunlight
and always remain extremely cold—about -200°C.
Mercury’s equatorial region experiences extreme changes, reaching 450°C at
perihelion when facing the Sun—hot enough to melt zinc.
In 1991 powerful radio telescopes on Earth revealed signs of
possible deposits of ice in the polar regions of Mercury.
These ice deposits occur in areas where sunlight never falls, such as crater
bottoms near both of the planet’s poles.
The ice on Mercury likely comes from comets or water-bearing meteorites that
have hit Mercury over the planet’s history up through the present.
Scientists use a technique called spectroscopy to conduct
studies of the light that Mercury reflects.
These studies indicate that planet has only an extremely thin atmosphere,
containing sodium and potassium.
The first up-close study of Mercury came with National
Aeronautics and Space Administration (NASA)’s Mariner 10 spacecraft, which
passed Mercury twice in 1974 and once in 1975.
It sent back pictures of a moonlike, crater-pocked surface. The spacecraft also
detected a magnetic field and provided data about the planet’s density and some
of its surface chemistry.
In 2004, NASA launched a much more ambitious mission to
Mercury – the so-called MESSENGER- MErcury Surface, Space ENvironment,
GEochemistry, and Ranging.
MESSENGER is set to enter orbit around Mercury in 2011. The first orbital image of Mercury was
obtained on March 29, 2011.
·1. Saturn's moon Titan has plenty of evidence of
organic (life) chemicals in its atmosphere.
·2. Life is known to exist only on Earth, but in 1986
NASA found what they thought might be fossils of microscopic living things in a
rock from Mars.
·3. Most scientists say life's basic chemicals formed
on the Earth. The astronomer Fred Hoyle said they came from space.
·4. Oxygen is circulated around the helmet in space
suits in order to prevent the visor from misting.
·5. The middle layers of space suits are blown up like
a balloon to press against the astronaut's body. Without this pressure, the
astronaut's body would boil!
·6. The gloves included in the space suit have silicon
rubber fingertips which allow the astronaut some sense of touch.
·7. The full cost of a spacesuit is about $11 million
although 70% of this is for the backpack and the control module.
·8. Ever wondered how the pull of gravity is calculated
between heavenly bodies? It's simple. Just multiply their masses together, and
then divide the total by the square of the distance between them.
·9. Glowing nebulae are named so because they give off
a dim, red light, as the hydrogen gas in them is heated by radiation from the
·10. The Drake Equation was proposed by astronomer Frank
Drake to work out how many civilizations there could be in our galaxy - and the
figure is in millions.
·11. SETI is the Search for ExtraTerrestrial
Intelligence - the program that analyzes radio signals from space for signs of
·12. The Milky Way galaxy we live in: is one among the
BILLIONS in space.
·13. The Milky Way galaxy is whirling rapidly, spinning
our sun and all its other stars at around 100 million km per hour.
·14. The Sun travels around the galaxy once every 200
million years – a journey of 100,000 light years.
·15. There may be a huge black hole in the very middle
of the most of the galaxies.
·16. The Universe is probably about 15 billion years
old, but the estimations vary.
·17. One problem with working out the age of the
Universe is that there are stars in our galaxy which are thought to be 14 to 18
billion years old – older than the estimated age of the Universe. So, either
the stars must be younger, or the Universe older.
·18. The very furthest galaxies are spreading away from
us at more than 90% of the speed of light.
·19. The Universe was once thought to be everything that
could ever exist, but recent theories about inflation (e.g. Big Bang) suggest
our universe may be just one of countless bubbles of space time.
·20. The Universe may have neither a centre nor an edge,
because according to Einstein’s theory of relativity, gravity bends all of
space time around into an endless curve.
·21. If you fell into a black hole, you would stretch like
·22. Matter spiraling into a black hole is torn apart
and glows so brightly that it creates the brightest objects in the Universe –
·23. The swirling gases around a black hole turn it into
an electrical generator, making it spout jets of electricity billions of
kilometers out into space.
·24. The opposite of black holes are estimated to be
white holes which spray out matter and light like fountains.
·25. A day in Mercury lasts approximately as long as 59
days on earth.
·26. Twice during Mercury’s orbit, it gets so close to
the Sun and speeds so much that the Sun seems to go backwards in the sky.
·27. Nicolaus Copernicus was the astronomer who first
suggested that the Sun was the centre, and that the Earth went round the sun.
·28. The ideas of Copernicus came not from looking at
the night sky, but from studying ancient astronomy.
·29. As the earth turns, the stars come back to the same
place in the night sky every 23 hours, 56 minutes and 4.09 seconds. This is a
sidereal day (star day).
·30. When Neil Armstrong stepped on the Moon for the
first time, he said these famous words: “That’s one small step for a man; one
giant leap for mankind.”
·31. From the moon, astronauts brought back 380 kg of Moon
·32. During the moon landing, a mirror was left on the
Moon’s surface to reflect a laser beam which measured the Moon’s distance from
the Earth with amazing accuracy.
·33. The stars in each constellation are named after a Greek
·34. The brightest star in each constellation is called
the Alpha Star, the next brightest Beta, and so on.
·35. The distance to the planets is measured by bouncing radar
signals off them and timing how long the signals take to get there and back.
·36. Spacecrafts have double hulls (outer coverings)
which protect them against other space objects that crash into them.
·37. Manned Spacecrafts have life support systems that
provide oxygen to breathe, usually mixed with nitrogen (as in ordinary air).
Charcoal filters out smells/
·38. Spacecrafts toilets have to get rid of waste in low
gravity conditions, Astronauts have to sit on a device which sucks away the
waste. Solid waste is dried and dumped in space, but the water is saved.
·39. A comet’s tail is made as it nears the Sun and
begins to melt. A vast plume of gas millions of kilometers across is blown out
behind by the solar wind. The tail is what you see, shining as the sunlight
·40. The Shoemaker-Levy 9 comet smashed into Jupiter in July
1994, with the biggest crash ever witnessed.
·41. Giant stars have burned all their hydrogen, and so burn
helium, fusing helium atoms to make carbon.
·42. The constellation of Cygnus, the Swan, contains the
very biggest star in the known universe – a hyper giant which is almost a
million times as big as the sun.
·43. Planet Uranus was discovered by William Herschel,
who wanted to name the planet George, after King George III, but Uranus was
·44. The first rockets were made 1,000 years ago in China.
·45. Robert Goddard launched the very first liquid-fuel
rocket in 1926.
·46. Over 100 artificial satellites are now launched
into space every year, a few of which are space telescopes.
·47. The lower a satellite’s orbit, the faster it must
fly to avoid falling back to the Earth. Most satellites fly in low orbits, 300
km from the earth.
·48. Hipparchus was the first astronomer to try to work out
how far away the Sun is.
·49. The red color of Mars is due to oxidized (rusted)
iron in its soil.
·50. Mars’s volcano Olympus Mons is the biggest in the
solar system. It covers the same area as Ireland and is three times higher than
our Mount Everest.
·51. Planets have magnetic field around them because of the
liquid iron in their cores. As the planets rotate, so the iron swirls,
generating electric currents that create the magnetic field.
·52. Earth’s atmosphere is the only atmosphere
discovered till date that human can breathe in.
·53. Earth’s atmosphere was formed from gases pouring
out from volcanoes.
·54. Jupiter has no surface for a spacecraft to land on
because it is made mostly from helium gas and hydrogen. The massive pull of
Jupiter’s gravity squeezes the hydrogen so hard that it is liquid.
·55. Jupiter spins right round in less than 10 hours which
means that the planet’s surface is moving at nearly 50,000 km/hr.
·56. The first successful planetary space probe was the USA’s
Mariner 2, which flew past Venus in 1962.
·57. Voyager 2 has flown over 6 billion km and is heading out
of the solar system after passing close to Neptune in 1989.
·58. To save fuel on journeys to distant planets, space probes
may use a nearby planet’s gravity to catapult them on their way. This is called
·59. Hubble’s law showed that Universe is getting bigger – and
so must have started very small. This led to the idea of Big Bang.
·60. It’s believed that it was the impact of a big
meteorite may have chilled the earth and wiped out all the dinosaurs.
·61. The first astronomers thought the regular pulses from far
space might be signals from aliens, and pulsars were jokingly called LGMs
(short for Little Green Men).
·62. Pulsars probably result from a supernova explosion - that
is why most are found in the flat disc of the Milky Way, where supernovae
·63. Three moons have yet been found to have their own moons:
Saturn’s moon Titan, Jupiter’s Lo, and Neptune’s Triton.
·64. The largest moon in the Solar System is the Jupiter’s
·65. Saturn is not solid, but is made almost entirely of
gas – mostly liquid hydrogen and helium. Only in the planet’s very small core
is there any rock.
·66. Winds ten times stronger than a hurricane on Earth
swirl around Saturn’s equator reaching up to 1100 km/h – and they never let up:
even for a moment.
·67. The first space station was the Soviet Salyut 1
launched in April 1971; its low orbit meant it stayed up only five months.
·68. In April 2001, Dennis Tito became the first space
tourist, ferried up to the ISS by the Russian Soyuz space shuttle.
·69. Einstein’s theory of general relativity shows that
gravity not only pulls on matter, but also space and even ‘Time’ itself.
·70. Since the star Deneb is 1800 light years away, we
see it as it was when the emperor Septimus Severius was ruling the Rome (AD
·71. With powerful telescopes, astronomers can see
galaxies 2 billion light years away. This means we see them as they were when
the only life forms in Earth were bacteria.
·72. The slowest rotating planet is Venus, which takes 243.01
days to turn around.
·73. The fastest spinning objects in the Universe are
neutron stars – these can rotate 500 times in just 1 second.
·74. In summer in Uranus, the sun does not set for 20
years. In winter, darkness lasts for 20 years. In autumn, the sun rises and
sets every 9 hours.
·75. Uranus’s moon Miranda is the weirdest moon of all.
It seems to have been blasted apart, and then put together again.
·76. Solar flares reach temperatures of 10 million °C and have
the energy of a million atom bombs.
·77. True binary stars are two stars held together by one
another’s gravity, which spend their lives whirling around together like a pair
·78. Halley predicted that a comet he had discovered would
return in 1758, 16 years after his death, and it really did. It was the first
time a comet’s arrival had been predicted, and the comet was named after him as
·79. Ceres is the biggest asteroid in the Solar System – 940
km across, and 0.0002% the size of the earth.
·80. The sun is about 5 billion years old and half a way through
its life – as a medium sized star it will probably live for around 10 billion
·81. Neptune’s mood Triton is the coldest place in the Solar
System, with surface temperatures of -236°C.
·82. Voyager 2 will beam back data until 2020 as it travels beyond
the edges of the Solar System.
·83. The Pioneer 10 and 11 probes carry metal plaques with
messages for aliens telling them about us.
·84. Einstein’s theory of Special Relativity (1905)
shows that all measurements are relative, including time and speed. In other
words, time and speed depends upon where you measure them.
·85. When things are falling, their acceleration cancels out
gravity, which is why astronauts in orbits are weightless.
·86. The first space telescope was the Copernicus, sent out in
·87. Astronauts learn Scuba diving which helps them to
deal with space walks.
·88. Weightlessness makes astronauts grow several centimeters
during a long mission.
·89. The first living creature in space was the dog
Laika on – board Sputnik 2 in 1957. Sadly, she died when the spacecraft’s
oxygen supply ran out.
·90. The first manned space flight was made in April
1961 by the Soviet Cosmonaut, Yuri Gagarin in Vostok 1.
·91. The heart of a star reaches 16 million °C. A grain
of sand this hot would kill someone 150 km away.
·92. Stars twinkle because we see them through the wafting of
·93. The sun weighs 2,000 trillion trillion tones – about
300,000 times as much as the Earth – even though it is made almost entirely of
hydrogen and helium, the lightest gases in the Universe.
·94. The sun gets hot because it is so big that the pressure
in its core is so tremendous – enough to force the nuclei of hydrogen atoms to
fuse to make helium atoms. This nuclear reaction is like a gigantic atom bomb
and it releases huge amounts of heat.
·95. The nuclear fusion reactions in the Sun’s core send
out billions of light photons every minute but they take 10 million years to
reach its surface.
·96. The Hiroshima bombs released 84 trillion joules of
energy. A supernova releases 125,000 trillion trillion times as such.
·97. The most distant galaxies (quasars) have red shifts
so big that they must be moving away from us at speeds approaching the speed of
·98. When light waves from distant galaxies are
stretched out his way, they look redder. This is called red shift.
·99. The moon’s gravity is 17% of the Earth’s so astronauts in
space suits can jump 4 m high on the moon.
·100. The moon is the only other world that humans have
set foot on. Because the moon has no atmosphere or wind, the footprints planted
in its dusty surface in 1969 by the Apollo astronauts are still there today,