How many extrasolar planets do we know about?

Thursday 8th April 2010
Submitted by Gareth Mitchell
Marcus Gill, Warwick

Extrasolar planets, or ‘exoplanets’, are planetary bodies that reside outside our Solar System. They orbit stars other than our Sun and though they have been hypothesised for over a hundred years, none had been confirmed until 1995. Michel Mayor and Didier Queloz of Geneva Observatory had been studying a star called 51 Pegasi. The object was wobbling, suggesting the gravitational influence of a large planet, about half the mass of Jupiter.

Over the intervening years, astronomers have gone on to discover many exoplanets. For the latest news in the field, keep an eye on The Extrasolar Planets Encyclopaedia (http://exoplanet.eu), a website regularly updated by the Paris Observatory. At the time of writing, the encyclopaedia lists 429 confirmed extrasolar planets. The last five to be added to the catalogue were reported simultaneously by a team at the Magellan Telescopes in Chile. They orbit different stars, but all have masses of the order of Jupiter.

GOT A QUESTION?

Scratching your head over a burning scientific conundrum? Submit your question and we'll get our esteemed panel of experts to answer it for you.

 

How do antibiotics kill bacteria?
previous qanda Article
Are we about to run out of IP addresses?
next qanda Article
Q&A Tabs

No. At least, not in the popular sense that creative people are more ‘right-brained’ than logical or analytical people are: a study that scanned the brains of over 1,000 people found...

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

Because of the orientation and tilt of their orbits, the eight major planets of the Solar System can never come into perfect alignment. The last time they appeared even in the same part of the...

Trees release oxygen when they use energy from sunlight to make glucose from carbon dioxide and water. Like all plants, trees also use oxygen when they split glucose back down to release energy to...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...

We use cookies to improve your experience of our website. Cookies perform functions like recognising you each time you visit and delivering advertising messages that are relevant to you. Read more here