• Question: Do we really have enough evidence to prove that there is another solar system apart from our one? Is there really another solar system out there?

    Asked by eshanip1017 to Alan, Francesca, Lilly, Nick on 19 Mar 2014.
    • Photo: Francesca Day

      Francesca Day answered on 19 Mar 2014:

      Yes! We know there are other stars out there for sure – you can see them if you look at the sky at night. It would be pretty odd if our sun was the only star with planets around it in the entire universe!

      There are also various experimental methods we can use to detect planets around other stars. For example, we can detect the slight dimming of the star’s light when the planet passes between it and the Earth. We notice that this dimming follows a regular patter, showing that the planet is indeed orbiting the star. We can also detect the very small gravitational pull the planet exerts on the star.

    • Photo: Alan Fitzsimmons

      Alan Fitzsimmons answered on 19 Mar 2014:

      Yes, right now there are 1,096 other Solars systems that have been found by astronomers.

      They are very difficult to find, and in most cases we’ve only see one big planet going around the star so far, but we do see lots of stars with more than one planet going around it.

      Here’s a real picture of four planets going around a star. The light from the star in the centre has been taken away, so we can see the 4 faint planets going around it.

    • Photo: Nick Wright

      Nick Wright answered on 21 Mar 2014:

      Oh yes definitely! We have been searching for planets around other stars for almost 20 years now, and especially in the last 5 years thanks to a NASA space telescope called Kepler, we have found lots of planets around other stars (read about Kepler here: http://kepler.nasa.gov).

      Kepler searches for the small changes in the light from distant stars that happens when a planet orbiting the star passes in front of the star and eclipses some of the light from the star. This causes the star to darken slightly for a few seconds or minutes, and that tells us there is a planet around that star. Scientists usually then keep watching the star for that same eclipse to happen again and again, and that can begin to tell us how big the planet is (from how much of the star’s light is being eclipsed) and how long it takes to go round it’s star (from the time gap between eclipses). This allows us to find out things about the planets.

      Sometimes scientists have found that stars have more than one planet around them, sometimes a big planet and a small planet, and so there is an example of another solar system apart from our one. In fact, sometimes we can actually take pictures of these other solar systems to prove that they exist. Here is one such picture of the solar system around the star HR8799:

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