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Optical SETI

Are We Alone? We built the world's first OSETI Telescope dedicated to finding out.

Whatever form an alien signal might take -- the faintest radio transmission, or a split-second pulse of light -- The Planetary Society is committed to discovering it. You can help us keep watch.

In 2006, The Planetary Society unveiled the first All-Sky Optical SETI (OSETI) telescope. Funded by The Planetary Society and operated by a Harvard University team, it's completely dedicated to capturing that one pulse of light that might be a communication. Over the years, our members have helped upgrade and improve the hardware for this program, searching the skies and processing enormous amounts of data.

With its 72-inch primary mirror, the OSETI Telescope is not only the only largest telescope in North America devoted to SETI; it is also the largest optical telescope in the U.S. east of the Mississippi. And, with cutting-edge processors, in just one second, it crunches more data than what is stored in all books in print.

OSETI Telescope Primary MIrror

Paul Horowitz

OSETI Telescope Primary MIrror
Construction of Planetary Society's Optical SETI telelscope in Oak Ridge, Massachusetts. Graduate student Jason Gallicchio is seen here reflected in the 1.8 meter primary mirror.

To date, the Optical SETI Telescope has completed over a thousand sets of observations. It takes 200 clear nights to cover the entire sky once and complete a snapshot. Then it starts again. Although dozens of triggers (pulses) have so far been sighted, all have been ruled out as communications. But vigilance is key: one signal from light-years away could prove we're not alone in the vastness of space -- and alter humanity's view of our place in the universe.

We're keeping close watch -- and making great strides -- but there is much more work to be done. We are in the process of installing amplifier boards to double the sensitivity of the OSETI Telescope. We are also working to completely automate the telescope to capture continuous data every possible minute of every night.

Visible light is thought to be a likely form of interstellar communication because visible light travels easily through space and suffers little interference. A tightly focused light beam, such as a laser, can be 10 times as bright as the Sun and be easily observed from enormous distances. Laser-like light signals are also unidirectional, making it possible to determine their source with great precision, and -- because of their higher frequencies -- can be used to send vast amounts of information.

But in order to receive a light signal from an alien civilization, we must be looking for it. With the Society's dedicated Optical SETI Telescope, our eyes are open.

Since its founding, The Planetary Society has been a leading advocate of the Search for Extraterrestrial Intelligence, supporting a wide variety of searches, making use of different approaches. Most of these -- and the largest ones -- have been radio SETI projects such as BETA, SERENDIP, SETI@home, and Southern SETI. Now, after decades of listening, The Planetary Society has turned its eyes to the skies to scan for possible light signals.

We don't know what we'll find. But we do know we'll find nothing if we don't keep searching.

Keep us searching. Donate to our Optical SETI project here >>

Project Updates

Let’s be careful about this “SETI” signal

Several readers have contacted me recently about reports that a group of international astronomers have detected a strong signal coming from a distant star that could be a sign of a high-technology civilization. Here’s my reaction: it’s interesting, but it’s definitely not the sign of an alien civilization—at least not yet.

Back on the Rails with OSETI

The Planetary Society sponsored all-sky optical SETI search at Harvard University went off the rails, telescope roof rails that is, but it is back on track and hunting the sky for ET.

Intro Astronomy 2014. Class 13: Galaxies, the Universe, Life

Discover the Universe including the Big Bang, dark matter, dark energy, galaxies, life and more in this video of class 13 of Bruce Betts' Introduction to Planetary Science and Astronomy class.

Cosmos with Cosmos Episode 12: Encyclopedia Galactica

Cosmos returns in fine form in its penultimate episode. Sagan explores the historical and scientific precedents for the search for extraterrestrial life (SETI) and our human desires to not be alone in the universe.

Planetary Radio: Looking for Intelligence in a Flash

An update on the Planetary Society's improved Optical SETI search, with Harvard's Paul Horowitz and Curtis Mead.

Our Improved Optical Search for ET

The Planetary Society Optical SETI (OSETI) Telescope was successfully upgraded and fully tested, and is now fully operational looking for aliens. Here are some updates on the performance and progress. In summary, the upgraded telescope is performing just as hoped and is scanning the skies.

Optical SETI Gets a Major Upgrade

The Planetary Society Optical SETI Telescope in Harvard, Massachusetts just got a major upgrade of its electronics.

One Man's Quest for SETI's Most Promising Signal

A review of Robert H. Gray's "The Elusive Wow: Searching for Extraterrestrial Intelligence."

SETI@home Following Up on Kepler Discoveries

Remember SETI@home? The ground-breaking computing project is now taking a look at candidate Earth-like planets that have been detected by NASA's Kepler space telescope.

Citizen Science projects for Planetary Science: Get Involved! Do Science!

Citizen Science projects let volunteers easily contribute to active science programs. They're useful when there is so much data it overwhelms computing algorithms (if they exist) or the scientific research team attempting to process it.

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