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The Square Kilometer Array

Posted by michael on from the lots-of-windex dept.

EyesWideOpen writes "A very ambitious project to build the world's largest radio telescope, named the Square Kilometer Array or SKA, is in its early design stages. As its name suggests the SKA will be one square kilometer in size if it gets built. The SKA consortium (consisting of Cal Tech, Cornell, SETI, the Max Planck Institute and Beijing Astronomical Observatory to name a few) hopes to build the telescope by 2010. "If they succeed the SKA will be so big and precise it will jump the world's current best, the American Very Large Array in New Mexico, by a factor of 100, both in sensitivity and resolution." It's interesting to note that the project is based on technology that will only exist in three, five or seven years -- to account for data rates of tens to hundreds of terabytes per second and storage in the petabytes -- so they're counting on Moore's law to hold true."

3 of 131 comments (clear)

  1. Why bigger is better by Space+cowboy · · Score: 5, Informative
    The reason radio telescopes have to be so much larger than their optical counterparts is due to the wavelengths they are looking for. For a given observation aperture, there's a simple rule-of-thumb which goes:


    Voltage gain ~= circumference / wavelength.
    ... with the power gain (the "magnification") being the voltage gain squared.

    Given that the wavelength of 'visible' light is approximately half a million times shorter than radio wave wavelengths, the collecting area has to be much larger to get the same antennae gain.

    An interesting corollary of this is that the naked eye is (very roughly) as powerful (at visible light wavelengths) as Arecibo is (at radio wavelengths). See the The seti league pages for more info...

    Simon.
    --
    Physicists get Hadrons!
  2. Re:Moore's Law by Detritus · · Score: 4, Informative

    Moore's Law is about the density of transistors in integrated circuits, not their speed or cost.

    --
    Mea navis aericumbens anguillis abundat
  3. Resolution by FlemLion · · Score: 4, Informative
    " If they succeed the SKA will be so big and precise it will jump the world's current best, the American Very Large Array in New Mexico, by a factor of 100, both in sensitivity and resolution."

    Fortunately it's only compared to the VLA in regards of resolution. Single radiotelescopes have no chance in hell to get to extreme resolutions. Resolution is all in the diameter, or baseline. Nothing you can do about, it's just basic physics. Fortunately you can have big holes in your telescope, or inversely just a few parts of the surface. Excactly the principle of the VLA and VLBI in radio frequencies and the VLTI for light. You can even find a simulation applet here

    In fact the earth itself is getting too small to get more resolution. Going into space is indeed being looked into, but not in the sense of a satellite like the Hubble orbiting the earth. That would hardly be worth the effort where radio astronomy is concerned. Having a baseline as long as the distance between the earth and the moon, now that would be an improvement. Plus, if it's built on the side that's always turned away from the earth, the telescope will be shielded from all the annoying interference created by all the radiochatter on earth, while it's still possible to look at the same piece of sky as an earth based telescope.

    In the visual spectrum, Darwin from ESA looks set to become the next record holder . A first technology demonstration/development flight in the form of SMART-2 is currently under development.