Since last year, a group of scientists has listened for alien radio signals at the Search for Extraterrestrial Intelligence institute.

When certain solar systems align, the team listens in with the Green Bank Telescope in Virginia and has spent 36 hours in total waiting to hear something, Discovery News reports. No alien signals have been found, however.

"We think the right strategy in SETI is a variety of strategies," Dan Werthimer, University of California Berkeley's director of SETI research, told Discovery News.

The project is all possible thanks to information discovered by the Kepler telescope, which NASA launched in 2009. The telescope's aim was to find planets that are around the same size as Earth and the right temperature to carry water, a sign of life. Since its launch, scientists working with the Kepler telescope have expanded the list of 1,792 planets outside of our solar system to include 962 more. They have also added 3,845 potential planets.

Out of the planets confirmed by the Kepler telescope (commonly referred to as Kepler planets), hundreds appear to be in multi-planetary systems. So, a team created the proposal to monitor these planets with radio telescopes, and an unnamed graduate student developed a computer program to determine when the Kepler planets would align with Earth.

"This is the first time in history we have had such specific and accurate information about other planetary systems and had the opportunity to consider how we could use it to improve the efficacy of our searches," explained Andrew Siemion, SETI scientist for University of California Berkeley, Netherlands Institute for Radio Astronomy and the Netherlands' Radboud University.

Currently, the team is awaiting approval on additional proposals.

In June, another SETI project will launch and target 30 different stars located within 13 light years of our Northern Hemisphere. The Panchromatic SETI will be conducted with the Green Bank Telescope and Netherlands' Low Frequency Array. Scientists are also hoping to receive observing time from Hawaii's Keck telescopes and Puerto Rico's Arecibo telescope.

"Typically, SETI searches cover only a very small region of the electromagnetic spectrum. We're going to do a thorough search of the bands ... in visible wavelengths, infrared and radio ... at a small number of targets," Wethimer said. "If we just select a very small number of targets then we can do a pretty comprehensive search."

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