Friday, 11 July 2014

  • mercury planet

  • Mercury is the closest planet to the sun in the solar system. Here are some scientific and interesting facts about this planet.

    1.) Mercury was named for the fleet-footed messenger of the gods in Roman mythology – the equivalent of the Greek’s Hermes.

    2.) Mercury is the first planet in distance from the Sun in the solar system. It is the smallest of the 8 planets.

    3.) This planet is the smallest of the rocky or terrestrial planets. The others are Venus, Earth, and Mars.

    4.) Mercury is the only rocky planet other than Earth to have a global magnetic field, which is about 1% as strong as Earth’s.

    5.) Like Venus, Mercury has no moons of its own.
    6.) Although it is the nearest planet to the Sun, it is only the second hottest planet. Venus is the hottest.

    7.) 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.

    8.) Mercury’s diameter is 4,879 km, about 40% the diameter of Earth or about 40% wider than the Moon.

    9.) Mercury’s volume and mass are about one-eighteenth that of Earth.

    10.) 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.

    11.) 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.

    12.) Jupiter’s moon Ganymede and Saturn’s moon Titan are larger than Mercury but are much less dense.

    13.) Mercury orbits the Sun every 87.97 Earth days at an average distance of approximately 58 million km.

    14.) 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 (aphelion).

    15.) As a result, sunlight is over 2.3 times stronger at perihelion than at aphelion.
    16.) 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.

    17.) 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.

    18.) When viewed from North Pole. Mercury turns counterclockwise (west to east) like Earth and most other planets.

    19.) 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.

    20.) Mercury rotates only once every 58.65 days, 2/3 of its period of revolution around the Sun.

    21.) 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.

    22.) Mercury preserves a record of a violent early period when asteroids, comets, and other debris bombarded the newly formed planets.

    23.) The craters on Mercury are shallower than those on the Moon.

    24.) The largest geological feature on Mercury is the Caloris Basin. It is the result of a massive ancient impact.

    25.) Mercury’s surface is crisscrossed by long escarpments or cliffs.
    26.) 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.

    27.) 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.

    29.) Mercury’s side facing the Sun gets very hot—up to 450°C—while the side facing away quickly cools to frigid temperatures, -183°.

    30.) The floors of craters at the north and south poles receive very little sunlight and always remain extremely cold—about -200°C.

     31.) Mercury’s equatorial region experiences extreme changes, reaching 450°C at perihelion when facing the Sun—hot enough to melt zinc.

    32.) In 1991 powerful radio telescopes on Earth revealed signs of possible deposits of ice in the polar regions of Mercury.

    33.) These ice deposits occur in areas where sunlight never falls, such as crater bottoms near both of the planet’s poles.

     34.) 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.

    35.) Scientists use a technique called spectroscopy to conduct studies of the light that Mercury reflects.
    36.) These studies indicate that planet has only an extremely thin atmosphere, containing sodium and potassium.

    37.) 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.

    38.) 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.

    39.) In 2004, NASA launched a much more ambitious mission to Mercury – the so-called MESSENGER- MErcury Surface, Space ENvironment, GEochemistry, and Ranging.

    40.) MESSENGER is set to enter orbit around Mercury in 2011. The first orbital image of Mercury was obtained on March 29, 2011.
    Facts About Space
    ·         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 nearby stars.
    ·         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 intelligent life.
    ·         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 spaghetti.
    ·         22. Matter spiraling into a black hole is torn apart and glows so brightly that it creates the brightest objects in the Universe – quasars.
    ·         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 rock.
    ·         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 alphabet.
    ·         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 catches it.
    ·         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 eventually chosen.
    ·         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 slingshot.
    ·         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 occur.
    ·         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 moon Ganymede.
    ·         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 200).
    ·         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 of dancers.
    ·         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 Halley’s Comet.
    ·         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 years.
    ·         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 1972.
    ·         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 the atmosphere.
    ·         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 light.
    ·         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, perfectly preserved.


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