Monday, 16 March 2015

universal facts-2

  • 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.