4 sunsets, 4 times the romance!

1 sunset on earth is beautiful enough, but imagine being able to see 4 different suns set. On the other hand anyone who knows anything about orbit mechanics will know that it's hard enough to imagine a planet in a binary star system (2 suns, 1 planet), but 4 stars and 1 planet seems impossible. Well, not surprisingly, such a system has been discovered (http://www.bbc.co.uk/news/science-environment-19950923), and so we welcome planet PH1 to the ever growing list of exoplanets (planets around other stars apart from our own Sun). This is a fascinating system as planets need to sit in stable orbits, that is a repeating orbit which will save it from being flung out into dark empty space. This isn't easy to imagine when you have 4 strongly attracting Stars nearby, nor how it formed in such a system.

Image courtesy of BBC. This is an Artists Impression of PH1, the new exoplanet found with 4 suns!

This is a nice example of Observation and Theoretical Astrophysics combining: observation discovers a phenomenon, allowing theorists to begin modelling it, now knowing that it is indeed possible in nature.

Incidentally, the PH name comes from Planet Hunters, a website (http://www.planethunters.org/) where you can, very simply, look for exoplanets. I just spent some time doing this and it's mildly addictive and fun to do.  All you have to do is look for dips in a collection of data points, pointing to a planet passing in front of a star. If you find one you even get your name mentioned!

 If they had only called it 'Angry Exoplanets' I'm sure many more people would play around with it!