Precision Is Everything

Finding gravity waves at the Hanford LIGO site will depend on technology at the leading edge of precise scientific measurement.

Some of the key features of the Laser Interferometer Gravitational-Wave Observatory:

The L-shaped, 2-mile tubes housing the laser detector will boast the world’s most sophisticated vacuum system.

The air in both tubes will be extremely low pressure - one-trillionth normal atmosphere - to reduce molecular movement.

The tubes have been adjusted to compensate for the curvature of the Earth.

Laser beams inside the tubes need to travel in a nearly perfect flat plane. Engineers found that the end of each uncorrected tube would be 4 feet lower than the other. The difference now: less than one inch.

The building housing the ultra-sensitive laser generators and vacuum equipment has one of the most vibration-proof floors ever designed.

The outer edge of the floor was poured separately as a 6-inch-wide strip. A 4-inch-thick caulk barrier separates the outer wall to the main floor. That huge slab is 90 yards wide, 100 yards long and 30 inches deep.

The stainless steel tubes will be baked for 30 days at 150 degrees Celsius.

That heating will eliminate the release of hydrogen from the steel, which could interfere with the precise measurements being taken.