January 9, 2012
Are We Still Alone? Scientists Analyze First Kepler Scans
The Search for Extraterrestrial Intelligence (SETI) project, which has begun its first analyses of the scans of 86 exoplanets uncovered by the Kepler Space Telescope, has found the first batch of hits within the data stream, according to scientists at University of California, Berkeley.
“We´ve started searching our Kepler SETI observations and our analyses have generated some of our first candidate signals,” the UC Berkeley scientists announced on Friday.
However, the team said additional analyses have shown that the signals are just old fashioned terrestrial radio frequency interference. But they are saying that is not necessarily a bad thing.
Although the interference comes from a source here on Earth, the detection of any artificial signal provides the team with a great opportunity to understand the kind of artificial (alien) signals they hope to eventually discover.
“These signals look similar to what we think might be produced from an extraterrestrial technology. They are narrow in frequency, much narrower than would be produced by any known astrophysical phenomena, and they drift in frequency with time, as we would expect because of the Doppler effect imposed by the relative motion of the transmitter and the receiving radio telescope,” said a statement on UC Berkeley´s website (http://seti.berkeley.edu/kepler-seti-interference).
The Berkeley scientists are processing the data taken from Kepler since early 2011. They have picked up some interesting signals from candidates -- referred to as Kepler Object of Interest (KOI). Although none so far seem to be anything more than terrestrial interference. If a single signal comes from multiple positions in the sky, as these ones do, it is most likely to be interference.
In this case, the narrow, shifting frequency of the signal matched the characteristics that researchers were expecting to see in an artificial radio signal from space. However, these characteristics also matched radio signals created from our own satellites around Earth.
The scientists tested the radio signals to determine where they originated by moving the telescope to scan other regions of space. After all, if a radio signal is being generated by a source in space, then pointing the telescope elsewhere would eliminate the detection of the signal. Since when doing so, the signal persisted, the team came to the conclusion that the signal was in fact coming from our own satellites.
The SETI project plans to continue to analyze the nearly 50 terabytes of data generated from its Kepler observations, and the group will update its blog with any additional results that pop up throughout the next many months.
The Kepler Space Telescope is currently looking for other exoplanets orbiting stars in the heavens. It does this by constantly looking at the same patch of sky, waiting for the distant worlds to pass in front of their parent stars. When one does pass in front of its parent -- called a “transit“ -- the starlight dims slightly, and Kepler registers it as a “candidate” exoplanet. Four transits must be completed before the world is confirmed.
One of the prime directives for the Kepler mission is to find Earth-sized exoplanets orbiting within the habitable zone of sun-like stars. The team said it would take 3.5 years for Kepler to confirm such an existence.
Looking for signals in the cosmos is like looking for a needle in the haystack; until now we were searching blind, starting even before we knew if there were any other planets out there or not. We now know there are billions of planets in our galaxy alone, based on Kepler data. And it is believed a majority of those planets are probably small, rocky worlds similar to Earth and Mars.
Determining how many of them are actually habitable may be impossible, but finding them will help narrow down the search, providing probable actual targets to turn the radio telescopes toward instead of just trying to search billions of stars overall.
Visit http://seti.berkeley.edu/kepler-seti-interference to read more and see images from the Kepler/SETI project.
On the Net:
- Search for Extraterrestrial Intelligence (SETI)
- Kepler Space Telescope
- University of California, Berkeley