21st Century radio telescope
Monday, October 30, 2006 9:35:56 AM
Radio waves have much greater lengths compared to light waves. They can pass through the interstellar dust that conceals all but 5 % of the universe from the optical view. The Radio Telescope is analogous to the optical telescope. Its antenna, like the optical objective, collects the radio waves. Modern radio instruments consist of several aerials connected via advanced computers to investigate one radio source. This particular array will be of the order of one square kilometre, hence the name SKA (Square Kilometre Array).
SKA will probe the early Universe, test Einstein's theory of gravity and even search for alien intelligent life. Scientists need to learn more about “dark energy”, pulsars, and black holes. Astronomers believe these objects may hold the key to a more complete theory of gravity.
It is likely that about half of the collecting area will be located in one place. Outrigger facilities will be up to thousands of km away. They will then send their data to be combined with those of the central station. This way of creating big effective collecting area is known as interferometry. This should allow SKA to see the hydrogen in the first stars and galaxies formed after the Big Bang.
The SKA will be able to pinpoint the positions of the nearest one-hundred-million galaxies. The emerging structure will hopefully reveal new details about "Dark Energy", this mysterious negative “something” that appears to be pushing the universe apart at an ever increasing speed.
With the help of SKA, we can investigate sources in the sky that radiate at centimetre to metre wavelengths. It will achieve sensitivities that are far beyond the reach of current radio telescopes.
Our TV transmits in wavelengths that the SKA will be sensitive to. If there is ET TV out there within a few hundred light-years, we would detect aliens with SKA.
The international space station ISS, and the International Linear Collider, CERN are so big scientific projects, that they need to be international. - The immense size of SKA means it also has to be internationalized. No single country has the money or the expertise to build SKA.
A key technical requirement of the central site is that there must be very low levels of man-made radio signals, because interference will mask the faint cosmic radio waves the telescope is designed to detect. For Australia, the central site would be in Western Australia. For South Africa, the central location would be in the Northern Cape. The facility will spill over into other African countries, if placed in SA. The BBC article has pictures of the two sites. You can click to enlarge image, and the first time you will be a bit surprised. I would place a radio telescope on the Moon. The far side of the Moon is in the radio shadow from the Earth.
The first elements of the SKA should come online in 2014. By 2020 the full network should be in operation. The estimated cost so far is 1.3bn euros (£0.9bn or $1.6bn).