Sunday, 17 July 2011

Largest Radio Telescope Ever Launched into Space is Set to Go


Exciting news in the world of radio astronomy this week, as several sources confirm that the long awaited Russian space telescope, RadioAstron, is due to launch on 18 July from Kazakhstan's Baikonur cosmodrome.

RadioAstron (pictured at Baikonur) will orbit the earth, and using interferometry, will become the the largest radio telescope ever built, with an observing area almost 30 times the Earth's diameter.

"There has never been a radio telescope that has been sent so far from the Earth," commented Yuri Kovalev, of Lebedev Physical Institute's Astro Space Center in Moscow, Russia, the managers of the project.

When it reaches an orbit that will extend almost as far as the moon, it will begin coordinating observations with telescopes on the ground, including the 100 metre radio telescopes in Green Bank, West Virginia, and Effelsberg, Germany, and the world's largest dish, the 305 metre Arecibo telescope in Puerto Rico.

The technique of interferometry is commonly used in radio astronomy. It involves linking telescopes from across the world in simultaneous observations of a single astronomical target. It is the basis for the Square Kilometre Array (SKA), which is being hailed - alongside the LHC - as one of the great science endeavours of the early 21st Century. Particle Decelerator reported on the SKA in April.

RadioAstron's principle science objective is to study the super massive black hole at the centre of Messier 87, a nearby galaxy. It will also be observing pulsars - spinning neutron stars - attempting to help astronomers understand how dust and gas is distributed around stars. But perhaps the most fascinating phenomena that RadioAstron will examine is natural masers. In electronics, a maser - "microwave amplification by stimulated emission of radiation" - is a device that amplifies electromagnetic waves. But masers occur in nature as well. Natural masers are found in outer space when water or other substances are excited by radiation from a star or by the energy of a collision.

As Rachel Courtland explains in New Scientist, RadioAstron "will also be able to register the radio waves emitted by water masers, clouds of water molecules that emit microwave radiation, in the discs of galaxies. This motion can be used to study the rotation rate of the galaxies and measure their distance from Earth. When combined with observations of how fast the galaxies are moving, astronomers can use the galaxy distances to calculate the present-day expansion rate of space and the effect of dark energy."

Conceived in Soviet times, RadioAstron has been delayed multiple times over the past two decades, so it's launch is being met with excitement and relief within the international radio astronomy community. The rocket carrying RadioAstron is due for launch from Baikonur at 0231 GMT on 18 July 2011.


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