Ground Control to Major Simpson...

It is news stories like this that make me think Homer Simpson is working for Nasa now (from the Guardian. Headline in bold):

Nasa aims to move Earth
Scientists' answer to global warming: nudge the planet farther from Sun

Scientists have found an unusual way to prevent our planet overheating: move it to a cooler spot.

All you have to do is hurtle a few comets at Earth, and its orbit will be altered. Our world will then be sent spinning into a safer, colder part of the solar system.

This startling idea of improving our interplanetary neighbourhood is the brainchild of a group of Nasa engineers and American astronomers who say their plan could add another six billion years to the useful lifetime of our planet - effectively doubling its working life.

...The plan put forward by Dr Laughlin, and his colleagues Don Korycansky and Fred Adams, involves carefully directing a comet or asteroid so that it sweeps close past our planet and transfers some of its gravitational energy to Earth.

'Earth's orbital speed would increase as a result and we would move to a higher orbit away from the Sun,' Laughlin said.

Engineers would then direct their comet so that it passed close to Jupiter or Saturn, where the reverse process would occur. It would pick up energy from one of these giant planets. Later its orbit would bring it back to Earth, and the process would be repeated.

What happens if you miss, and one of those comets happens to hit the Earth?

DOH!