Storm clouds gathering as spring comes to Uranus
Wednesday 10 April 1996
It's springtime on the planet Uranus. And just as April showers herald spring here in Britain, the clouds are gathering in the skies above Uranus. The difference is that the seasons on Uranus last for more than 20 of our earth years. Not even Gene Kelly would have kept on singing in the rain for that long.
The sight of a few wisps of cloud in the atmosphere of this distant gas giant planet has taken astronomers by surprise, according to Dr Heidi Hammel, of the Massachusetts Institute of Technology, who lectured on "Exploring the Giant Planets with the Hubble space telescope" at the conference.
When, a decade ago, it was visited by the Voyager space probe, the pictures revealed an apparently featureless disk, but now the Hubble Space Telescope is showing that clouds are forming, the harbinger of changing weather. "In the next few years I think there may be interesting things happening on Uranus," Dr Hammel said.
She added: "Uranus is so peculiar because its rotational axis is tipped over 90 degrees." The Earth's axis points almost vertically upwards out of the disk of the solar system whereas the axis of Uranus lies in the plane of the system. This means that, loosely speaking, for about a quarter of the orbit, the "North" Pole points at the sun, for the next quarter the equator points sunwards, for the next quarter it's the South Pole and then its the equator again.
Dr Hammel believes the reason Voyager took such disappointing pictures of the planet "just happened to be an accident of timing. Uranus has times when it is active and that depends on what season it is. We're not used to thinking about seasons that are 20 years long".
Astronomers in the 1890s had reported that they observed clouded bands on Uranus although such clouds had not been observed since, Dr Hammel said. Now the images of the Hubble telescope, which is able to picture the atmosphere of the planet developing over time are "rapidly changing our perception of these planets and how stable they are."
International Women's Day 2014: The shocking statistics that show why it is still so important
Feminist quotes to inspire you on the International Women's Day
Belle Knox: How the porn star student from Duke University became bigger than Justin Bieber
International Women's Day 2014: Mothers and daughters describe their hopes and dreams in touching photographs
Liam Neeson on death of wife Natasha Richardson: ‘When I hear the door opening, I still think I’m going to hear her’
Apple's Tim Cook: Business isn’t just about making profit
Thousands of young people forced to go without food after benefits wrongly stopped under 'draconian' new sanctions regime
Ukraine crisis: New navy chief 'defects' and surrenders Crimean HQ as Putin claims ultranationalists forced intervention
Britain's top vet sparks controversy with call for ban on slashing animals' throats in 'ritual' slaughters for halal and kosher meat products
Ukraine crisis: Russia dismisses '3am ultimatum' as 'total nonsense'
If you're horrified by a flame-roasted dog, you should be shocked at a hog roast
- 1 International Women's Day 2014: The shocking statistics that show why it is still so important
- 3 Orgasm machine to deliver climax at the push of a button
- 4 Too upsetting? Academy members voted for Oscar-winning 12 Years A Slave 'without watching it'
£12000 per annum: Inspiring Interns: A small but growing chain of boutique hot...
£12000 per annum: Inspiring Interns: The company works with Tier 1 FTSE 100 Ba...
£45 - 60k Per Annum: Charter Selection: Highly profitable leisure brand, marke...
£30000 - £50000 per annum + Highly Competitive Salary: Austen Lloyd: Residenti...