The Hanford observatory that detected gravitational waves has revamped its popular tours of the Laser Interferometer Gravitational-wave Observatory, or LIGO, near Richland.
Starting Saturday, LIGO will offer tours just one a day a month, but will offer some activities to appeal to children and add more flexibility for visitors.
Visitors can show up anytime between 1:30 and 4:30 p.m. Saturday, but Friday tours no longer will be offered. The monthly tours have been drawing about 100 visitors on Saturdays and about 40 on Fridays for a single tour each day.
On the second Saturday of each month, participants can tour the observatory at 1:30 or 3:30 p.m., including a stop in the control room and a walk outside to see the two 2.5-mile-long vacuum tubes stretching at right angles across the Hanford landscape.
A laser beam is split and sent down each tube. Any movement keeps the beam from recombining perfectly as it bounces back off mirrors suspended at the end of each tube. If the same movement is detected at LIGO Hanford’s twin observatory in Louisiana, it may have been caused by a gravitational wave.
The tours are planned so participants in both tours can hear a LIGO scientist or engineer give a talk at 3 p.m. aimed at non-scientists, covering topics such as Albert Einstein’s general theory of relativity or detections made at the observatory.
Visitors also can learn some science at new hands-on activities prepared for kids, but also popular with adults. They include a demonstration of warped space and why objects orbit, plus other astronomical-themed activities to help people understand the science used at LIGO.
The tours are generally recommended for middle-school-aged children and older, but all ages are welcome.
LIGO Hanford and its twin observatory in Louisiana detected gravitational waves for the first time in September 2015, about a century after Einstein predicted their existence.
The waves were created by two black holes that collided 1.3 billion years ago, sending ripples through space and time that passed through the Earth.
Before the year was up, a second detection was made of gravitational waves produced by black holes colliding.
The observatory is in operation, having started a new run to search for gravitational waves in November 2016.
In addition to second Saturday tours, groups of 15 or more can schedule tours. Call 509-372-8248.
To reach LIGO, take Highway 240 to Hanford Route 10 — which is between mileposts 20 and 21 — and then drive north for about 5.5 miles.