2007-03-07 03:49:30 · 4 answers · asked by thirteen 1 in Science & Mathematics ➔ Physics
Because radio wavelengths are "much bigger" than visible light wavelengths. Image resolution is a function of both aperture size and wavelength, so for the same image resolving power, you need a larger aperture for longer wavelengths.
2007-03-07 03:56:12 · answer #1 · answered by Scythian1950 7 · 1⤊ 0⤋
The gain of a dish antenna is inversely proportional to the wavelength. Therefor for radio energy, a dish has to be very large to include a significant amount of wavelengths across its spam when compared to light. Plus it's impractical to build a 200 foot mirror.
2007-03-07 11:56:40 · answer #2 · answered by Gene 7 · 1⤊ 0⤋
Rufus Cat is right: because it's possible due to longer wavelengths.
If it was possible to build optical telescopes that big,
the astronomers would definetely go for it. The goal
is not have the same resolution at all wavelengths, but
to have the best possible resolution for any particular
wavelength.
2007-03-07 12:11:36 · answer #3 · answered by Alexander 6 · 1⤊ 0⤋
1) Because it is possible to build them that big - but mirrors for light are more difficult as they must be accurate to a fraction of a wavelength. (Radio 10m to 10mm; light 500nm)
2) Work out the size/wavelength and the difference is likely to reverse!.
2007-03-07 11:55:51 · answer #4 · answered by Rufus Cat 4 · 1⤊ 0⤋