Real or Counterfeit - the tale of the Big Dog

For a few months here at LIGO, there has been a lot of hushed but excited talk that a gravitational-wave detection event may have been observed during the Sixth Science Run underway last September. The discussions were discreet, unofficial, and always qualified as "may have been observed." It is the essence of the scientific method not to announce any conclusion until results have been checked, rechecked, and checked again. Nevertheless, the excitement was conspicuous and the code words "big dog" could be heard in every hallway, around every coffee pot. Why "big dog"? The possible event appeared to originate in the area of the Canis Major constellation.

At the same time, LIGO scientists and engineers were always aware that a fake signal - a "blind injection" - might be deliberately added to the data by top management to test the data analysis methods and the personnel monitoring the science run. So the signal might be spurious. Or it might be authentic. All of LIGO was enjoined to act on the assumption that the event was as real as it appeared to be.

After months of preparation, planning, research and due diligence, it was announced that the answer to the Big Dog event - was it real or fake? - would be disclosed at the March LIGO Scientific Collaboration (LSC) in California. The procedure would be this: Jay Marx, LIGO Executive Director, would stand before the hundreds of LSC collaborators gathered in the vast assembly hall of the Embassy Suites Hotel. Video cameras would simultaneously broadcast his actions to LSC outposts around the world via the internet. Marx would exhibit a sealed envelope, open it, and reveal its contents. If the envelope contained a slip of paper, then the Big Dog event was a fake, only a test. But if the envelope were empty, then the event was real and all pandemonium could be expected to break out.

After about two hours into the first day of the LSC meeting, Jay Marx took his position at center stage in front of the assembly. He displayed the envelope. He opened it. A tense hush fell over the crowd. He revealed the answer.

So was the Big Dog an authentic gravitational-wave detection event? Or was it instead a test? (Hint: when the event is real, expect this blog to proclaim it in 10-inch high letters.)

Read more here:

Discover Magazine Online

Discovery News Online


The full story at the official LIGO website, LIGO.ORG

Popular Posts