Saturday, January 15, 2011

Scientists plan to look up Uranus using a probe


That's right, British scientists are interested in probing Uranus and are leading plans to send a probe to explore the giant ice planet. They have put forward a detailed proposal to the European Space Agency to launch a joint mission with NASA to the distant world, 1.8 billion miles from the sun.

Need any help finding Uranus? Some people can't tell it from a hole in the ground. But for the next few months, it'll be next to Jupiter. Anyway, this probe would give scientists their first close-up views of Uranus since NASA’s Voyager 2 flew past and captured fleeting pictures 25 years ago. The £400million mission is designed to go in orbit to study the rings around Uranus and answer questions such as why it gives off so little heat... but so much wind (blowing at more than 500 mph).

The first man to declare, "I see Uranus!", was Sir William Herschel from Bath, England, in 1781. The planet is unusual because it is tilted right over on its side. Astronomers believe this was caused when Uranus was given a mighty slap by another world in some long-ago cosmic collision.

More than 160 scientists are backing the Uranus Pathfinder project which is led by Dr Chris Arridge, of University College London’s Mullard Space Science Laboratory in Surrey. He told Skymania in an exclusive interview: “We’ve only really scratched the surface of Uranus. It is very difficult to observe from Earth because any detail is smeared out. Since Voyager flew by we know the rings and atmosphere have changed. We need close-up measurements. Uranus is ripe for learning a lot from. There's a lot to explore there. It is so different among the planets."

“We tend to group Jupiter, Saturn, Uranus and Neptune as the gas giant planets. But Jupiter and Saturn are dominated by hydrogen and helium with small rocky cores." He says. “When you go to Uranus and Neptune you find their composition is dominated a lot more by rock and ice. There is a lot more water in their atmospheres, a lot more methane.”

He added: “One of the big mysteries about Uranus is that it doesn’t emit much heat at all. Its axis is also highly tilted to its orbit so essentially it rolls around the solar system. It is thought that something the size of Mars or Earth hit Uranus early in the solar system and tilted it into its side, and that may have caused a massive loss of primordial heat.”

Uranus takes 84 years to orbit the Sun which leads to extreme seasons. Dr Arridge explains: “Because there is so little heat coming from inside Uranus, its atmosphere is completely driven by force of sunlight. And because it has got this large tilt in its axis one pole is continually in sunlight for 42 years while the other is in darkness and then the situation is reversed for 42 years.”

The nuclear-powered probe for Uranus, which the scientists hope to launch in 2021, would take an incredible 15 years to travel the vast distance to it's destination. It will be sent zipping past other planets (including Venus and Saturn) to help build up speed, like a game of interplanetary snooker. Finally it will go into orbit around Uranus to study the planet, its five main moons and other smaller natural satellites.

Uranus Pathfinder is being proposed as an M-class (medium-class) mission for ESA. But Dr Arridge said: “We see this as medium scale only in terms of price. For the amount of science you get back, it is a large scale mission for quite low cost.”

Is Uranus ready?

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