Replica Solar System discovered 5,000 light years away

BBC News

Back in ancient times most people thought that our planet was at the center of the Universe. Then we thought it was the Sun, and not too long after we realized that we’re actually just a tiny part of one of billions of galaxies in a Universe filled with trillions of other stars. Just over a decade ago one of the last things that we thought might be unique about our Solar System was disproved – the first ever planet outside our Solar System (an ‘exoplanet’ for short) was discovered around another Sun.

Wikipedia Now our uniqueness has been eroded away a little bit more – a British team of astronomers has discovered what looks a bit like a replica of our own Solar System, orbiting around a star 5000 light-years away.

OK, it’s not an exact replica, but the resemblance is quite striking. Two giant gassy planets (like Jupiter and Saturn in our own Solar System) have the same mass ratio to their sun as Jupiter and Saturn have to our own Sun. And the size of their orbit is proportionally the same as the orbits of Jupiter and Saturn. (The star in the newly discovered system is only about half the size of our Sun, hence the reason why all the figures are given as ratios). The orbital period of the giants is about the same too.

So what about a copy of Earth and the other inner, rocky planets? Well, the scientists didn’t actually discover a new Earth, but they say that the existence of an Earth-like planet is quite likely because there is plenty of empty space in between the gas giants and the star.

Wikipedia Unfortunately there’s not much chance of us discovering any more planets in this system – at least not yet, anyway. Current techniques simply aren’t powerful enough to see such small objects so far away.

But wait a minute… if the system’s so far away, how could we detect that the giant gas planets were there? They’re pretty tiny too, surely, compared to the size of their sun?

They used a clever trick called ‘gravitational lensing’, which involves the effect first predicted by Einstein that if you put a heavy object (like a star) in front of another object (like another star further away), the star in front will bend the light from the star behind because gravity bends light. This enables us to see faraway objects much bigger than we would usually be able to see them. (Click here to read more about gravitational lensing, and how it enabled the Hubble Space Telescope to see a galaxy 13 billion light years away.)

Since we don’t know for definite that there’s a replica Earth in this system, should we really be getting so excited? I think the answer should definitely be yes – in the decade since we first discovered extrasolar planets, 300 planets outside our Solar System have been discovered. The more variation among these planets, the more chance of eventually finding ET. And that would be seriously cool.

Click here for NASA’s excellent exoplanet website: PlanetQuest.

Advertisements

2 Responses

  1. I think it’s high time that someone discovered how to move faster than light speed — warp speed sounds good to me — so we can go and visit (or at least send a probe). How long would it take something like the Huygens probe to get there… 10,000 years?

  2. Good point – although I’m not sure that’s really possible. At least not according to Einstein. 😆

    I’m not sure exactly how fast space probes go, but based on the fact that Voyager 1 has traveled about 0.001599 light years in 30 years, it would take about 100,000 years for Voyager to reach the new planet system. (Please tell me if I’ve done that calculation wrong – it’s a bit complicated!). I’m an optimistic person normally, but I think in this case I might have to admit that I will probably be dead by then. 🙂

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: