Far off the main road in northeastern California, follow the signs to Hat Creek Radio Observatory and you'll come to outer-space terrain, dotted with what my six-year-old calls "Dish Aliens."
It's the Allen Telescope Array (ATA) established in 2007 by the SETI Institute. SETI stands for the Search for Extraterrestrial Intelligence – and yes, they’re well-respected scientists who are looking for aliens.
With very few tourists in these parts, the self-guided tour (rather than a ticket office and docents) solidifies the remote, lonely nature of this valley, walled off by mountains. The mountains form a natural shield against radio interference from surrounding cities, so astronomers can listen for weak radio waves received from outer space.
Forty-two radio telescopes currently dot the valley. The SETI Institute hopes to have 350 completed, which will make it the largest radio observatory in the world. The problem is that they lack funding. Currently, to keep operating costs down, SETI uses crowd-funding or finding private sponsors on-line to support their efforts.
They also have a warehouse-size tent cluttered with tractors, ladders and ordinary tools. Here, a team of scientists build their telescopes with “off-the-shelf” parts rather than expensive equipment. They also assemble the radio telescopes on site.
Beside the warehouse, the radio telescopes hum twenty-four hours a day, 365 days a year.
Dr. William Welch designed the radio telescopes. Welch is the husband of Dr. Jill Tarter – the outgoing director of SETI. And Dr. Tarter also happens to be the inspiration for Carl Sagan’s protagonist in the book Contact.
Welch designed a primary reflector (the dish) for detecting signals from outer space. A metallic snout (called a shroud) points downward and blocks radio waves coming from the ground. Inside the radio telescope, a receiver shaped like a pyramid of spikes captures different wavelengths; shorter spikes capture short wavelengths, and longer spikes capture the long wavelengths.
A single dish alien has the widest frequency ever built in a single receiver: 50 MHz to 11 Ghz. You can walk right up to the radio telescopes to listen, touch and admire their eerie charm.
A one-story building also houses a processing lab. Inside, metal hubs sprout with wires. The radio signals received from the telescopes come here for analysis. Scientists then look for “narrow-band” signals, which are believed to be artificial.
Have they communicated with extraterrestrials? Not yet. However, the by-products of their research have been many. In particular, the Hat Creek Radio Observatory currently follows NASA’s Kepler telescope. After Kepler finds a star, SETI listens to approximately three planets every day, hearing each frequency for 93 seconds. In this way they're able to listen to thousands of planets every year.
The Hat Creek Radio Observatory asks you to turn off all cell phones during your visit because they can potentially bring down an entire array. So if SETI scientists happen to contact aliens while you’re visiting, you won’t be able to call home.
But once you leave, SETI encourages tourists to hook into their computers and yes, help them find E.T. Go for it at setilive.org.