Hanford LIGO announcement set for Thursday

UPDATE: Another finding announced. Read about it here.

LIGO at Hanford and its twin observatory in Louisiana are set to make an announcement on Thursday.

While officials are not saying what’s up, the Laser Interferometer Gravitational Wave Observatories started their latest scientific run about six months ago.

In their previous testing and observation run, the observatories made scientific history.

They detected the existence of gravitational waves for the first time, 100 years after Albert Einstein predicted their existence in 1915. And then they detected them again.

Twice LIGO Hanford near Richland and LIGO Livingston in Louisiana announced that ripples through space and time from collisions of black holes more than 1 billion years ago had been observed passing through Earth.

Detecting the waves as they ripple through Earth holds promise to open up a new way for scientists to learn about the universe, much of which may be made up of matter unlike what we’re familiar with on Earth.

The observatories had been shut down for about five years for a major overhaul to make them 10 times more sensitive before the previous operating run. The improved observatories, called Advanced LIGO, operated from September 2015 to January 2016.

The gravitational waves were observed on Sept. 14, 2015, and three months later on Christmas Day.

Then the observatories were shut down again to evaluate performance and make improvements to their lasers, electronics and optics. At LIGO Hanford, the power into the interferometer was increased and the stability of the detector was improved.

The Hanford and Louisiana facilities began searching again for gravitational waves late this past November with a planned run of about six months.

Detecting a gravitational wave at both observatories helps confirm the finding.

Gravitational waves are powerful enough to compress objects as they pass through, turning a circle into an ellipse.

The LIGOs are designed to detect that tiny movement using high-powered laser beams bounced off mirrors suspended at the end of two 2.5-mile vacuum tubes. At Hanford, the tubes extend across the shrub steppe north of Richland.

The laser beam is split, with half going down each of the tubes, which are arranged at right angles to catch any lengthening of one and shortening of the other by a gravitational wave. If the mirrors change distance, the beam will not perfectly combine as its two parts bounce off the mirrors and return.

Gravitational waves are caused by violent events in space. Although waves from the mergers of black holes have been detected so far by LIGO, they also can be caused by events such as the mergers of pairs of neutron stars or by supernovae.

LIGO Hanford has public tours at 1:30 and 3:30 p.m. the second Saturday of each month. At 3 p.m., a LIGO scientists or engineer gives a talk. Doors open at 1 p.m. and no reservations are required.

Directions are posted at bit.ly/HanfordLIGOdirections.

This story was originally published May 28, 2017 at 5:33 PM with the headline "Hanford LIGO announcement set for Thursday."