Astronomy for all
Thursday January 19th 2012

Communicating with distant stars using the Gravitational Lens – Story of the Week


Each week I select a paper from my news feed which I liked the most. This one is a bit more technical than most but the idea is very interesting. This is an amazing technique which was recently used in the detection of an extra solar planet in the Andromeda galaxy.  There is a proposal to use the gravitational lens of a our Sun to help image nearby exoplanets,  although the equipment would have to be approximately 550 astronomical units (AU is the distance from the Sun to the Earth) at the point of the gravitational lens.

The article I have selected describes a new paper which discusses using the gravity lens and its applications for low energy radio transmission between stars with low bit rate errors.  This basically means that a highly reliable communication link between us and another star is possible. Of course we have to get there and set up a receiver.  I’ll let you read the review for more complete details.

…the surprise is that… for the Sun-Alpha Cen direct radio bridge exploiting both the two gravitational lenses, this minimum transmitted power is incredibly… small! Actually it just equals less than 10-4 watts, i.e. one tenth of a milliwatt is enough to have perfect communication between the Sun and Alpha Cen through two 12-meter FOCAL spacecraft antennas.

The article is a Centauri Dreams review of a paper by Maccone, “Interstellar Radio Links Enhanced by Exploiting the Sun as a Gravitational Lens,” presented at the recent IAC.

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