• Question: Which telescope is furthest from Earth?

    Asked by to Nat, Nate, Roberto, Sam, Sarah on 24 Jun 2014. This question was also asked by .
    • Photo: Nate Bastian

      Nate Bastian answered on 24 Jun 2014:


      It depends a bit on how to define a telescope. In principle, any camera with a lens could be seen as a telescope. In this case, Voyager is the most distant object that human kind has ever sent out, and it has a camera, so it would be the winner.

      WMAP is, and the next big space telescope (James Webb Space Telescope – JWST) will be, in an orbit past the moon (at L2). So these are the furthest from earth, and are dedicated telescopes.

    • Photo: Roberto Trotta

      Roberto Trotta answered on 24 Jun 2014:


      There are two main places in space where we send telescopes: one is around the Earth, with telescopes going around once every 90 minutes. This is where for example the Hubble Space Telescope is. This is not very far away at all – only about 160 km up. This is so close that we can send repair crews to fix the telescope if something goes wrong. Hubble was repaired and upgraded three times already.

      But if you want the best possible place to go and make observations from, then you’d send your telescope to a point in space called “Lagrange Point L2”. This is a special place, about 1.5 million km away from the Earth, in the opposite direction to the Sun. If you put a telescope there, the telescope can keep its position without spending any fuel, because the gravitational force of the Sun and Earth cancel out almost exactly. Plus, it’s very far away from the Earth, so the telescope can observe the Universe in a better environment. Here is a picture of where L2 is:

      http://webb.nasa.gov/orbit.html

      This is the furthest out a telescope has been sent. Of course, space probes can travel much farther (the two Voyager probes have now reached the end of the solar system), but those are not telescopes in the common meaning of the term.

    • Photo: Sarah Casewell

      Sarah Casewell answered on 24 Jun 2014:


      Telescopes that orbit the Earth are in a variety or orbits – most have been put in low earth orbit, which means they go round every 90 mins.

      Some of the largest telescopes we’re building at the moment like the James Webb space telescope will be at what is called L2 – they’ll be out past the moon at a stable gravity spot.

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