Monday, 16 March 2015
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.
Earth’s atmosphere is the only atmosphere discovered till date that human can breathe in.
Earth’s atmosphere was formed from gases pouring out from volcanoes.
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.
Jupiter spins right round in less than 10 hours which means that the planet’s surface is moving at nearly 50,000 km/hr.
The first successful planetary space probe was the USA’s Mariner 2, which flew past Venus in 1962.
Voyager 2 has flown over 6 billion km and is heading out of the solar system after passing close to Neptune in 1989.
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.
Hubble’s law showed that Universe is getting bigger – and so must have started very small. This led to the idea of Big Bang.
It’s believed that it was the impact of a big meteorite may have chilled the earth and wiped out all the dinosaurs.
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).
Pulsars probably result from a supernova explosion - that is why most are found in the flat disc of the Milky Way, where supernovae occur.
Three moons have yet been found to have their own moons: Saturn’s moon Titan, Jupiter’s Lo, and Neptune’s Triton.
The largest moon in the Solar System is the Jupiter’s moon Ganymede.
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.
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.
The first space station was the Soviet Salyut 1 launched in April 1971; its low orbit meant it stayed up only five months.
In April 2001, Dennis Tito became the first space tourist, ferried up to the ISS by the Russian Soyuz space shuttle.
Einstein’s theory of general relativity shows that gravity not only pulls on matter, but also space and even ‘Time’ itself.
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).
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.
The slowest rotating planet is Venus, which takes 243.01 days to turn around.
The fastest spinning objects in the Universe are neutron stars – these can rotate 500 times in just 1 second.
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.
Uranus’s moon Miranda is the weirdest moon of all. It seems to have been blasted apart, and then put together again.
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