• Question: When looking at distant objects, are we looking at the past?

    Asked by lilygrainger to Anouk, Chris, Judith, Leisha, Seyyed on 13 Jun 2012.
    • Photo: Chris Kettle

      Chris Kettle answered on 13 Jun 2012:

      Yes would be the short answer. Think about stories about supernovas that you’ll read about in New Scientist. Light takes time to travel, its superfast, but is not instantaneuos. So, the further you are from an object, the greater the distance the light will have to travel to be seen.In the case of space you may have heard of light years? This is the time in years it has taken for the light to reach us. If the event occurred thousands of light years ago then it is well in the past.
      Now it gets trickier the closer you get to an object. Light moves at around 300million miles a second. Anything we “see” happening on Earth is not technically in the past as the time between the event occuring and hitting our retinas is so smaller that it is imperceivable. There will be a lag between the eye receiving the light and our brains processing the information- so i guess everything we “see” is in the past, technically, and the further away things when we see them the further in the past they occurred.

    • Photo: Judith Sleeman

      Judith Sleeman answered on 13 Jun 2012:

      When looking over long distances, definitely yes, for the reasons Chris says. That’s why astrophysicists always want bigger telescopes and fancier satellites, trying to look at the way back to the Big Bang and even before. The light that comes back from space through the telescopes gets distorted on the way, so astronomers uses fancy maths programmes to get a properly focused image. The process is called deconvolution. We sometimes use the same maths to get properly focused images of cells from down the microscope (well, I put the images into a computer and that does the fancy maths!). So, the astronomers developed the maths to look at massive thing at huge distances, and we use them to look at tiny things up really close.

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