• Question: what is a hubble space telescope

    Asked by to Nate, Nat, Roberto, Sam, Sarah on 16 Jun 2014. This question was also asked by , , , , , .
    • Photo: Sarah Casewell

      Sarah Casewell answered on 16 Jun 2014:

      The hubble space telescope is a 2.5m telescope orbiting the earth! It orbits us once every 90 minutes and has been observing space and our solar system for 25 years now! Because it’s outside the Earth’s atmosphere it can see very faint objects very clearly. Even larger telescopes on Earth get affected by the way our atmosphere moves – currents moving heat from hot areas to cold areas cause shimmering in our images that mean we can’t get very sharp images.
      If you’re in space you can see these things much better, even with a smaller telescope!

    • Photo: Sam Connolly

      Sam Connolly answered on 17 Jun 2014:

      As Sarah says, it’s a telescope in space! It’s quite special because it’s the only space telescope that can see ‘optical’ light, which is the light we can see. There are a lot of other space telescopes (maybe 10-20 at the moment), but most of them look at X-rays, gamma-rays or infrared light, because it doesn’t get through the atmosphere as easily as optical light.

      There used to be a limit on how well you could see optical light through the atmosphere, no matter how big your telescope, which is why they built Hubble, but recently we’ve worked out how to get around the problem using something called ‘adaptive optics’, which is one of the reasons why there hasn’t been a new optical space telescope since Hubble was launched, but have been lots of other types. There is a similar telescope being launched soonish called the James Webb Space Telescope though, which will be able to see things ten times fainter than Hubble!

    • Photo: Roberto Trotta

      Roberto Trotta answered on 17 Jun 2014:

      It’s a flying telescope, that orbits the earth — that’s to say, it goes around the earth every 90 minutes. It’s got a mirror 2.4 diameter in size: the bigger the mirror, the more light you can collect and the further out in the universe you can see.

      On earth, we do have even bigger telescopes, up to 10m large. But the Hubble has a great advantage: it is in space, where there is no air, and therefore it can see much better distant stars and galaxies. That’s because air is always trembling and this makes it harder for telescopes on earth to see the finer details of the objects they are looking at.

      Soon there will be an even more powerful, bigger space telescope, called the James Webb Space Telescope, which will replace Hubble and give even better images.

    • Photo: Natasha Stephen

      Natasha Stephen answered on 18 Jun 2014:

      This is a great question and these are all really good answers! I love the HST, it’s furthered our knowledge and understanding of the universe around us so much that even with new telescopes such as the James Webb Space Telescope, I think Hubble will always be my favourite!

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