When Worlds Collide

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35 years ago, I was finishing my sophomore year and looking for a summer job on campus. As newly married students, my wife and I would be spending the summer on-campus and together, for the first time. The teaching assistant for my physics class, Yekta Gursel, suggested I take a job helping him assemble a new piece of equipment: a gravity wave detector.

"Someday, this thing is going to detect two black holes colliding", he said. Also, it paid $6 an hour. Yekta and I spent the summer bolting together stainless steel pipes, vacuum pumps and glass bell jars. We built a simple system to isolate vibrations using rubber toy cars and blocks of lead. When the summer was over, I continued working on the project, and even built an optical filter for it as a senior thesis project.

By the time I graduated, the project was gaining momentum, but a couple of graduate students had written theses with "null results": that is, no gravity wave found. I thought, "I don't have the patience for this--it could be years before they detect one." I moved on to other physics problems, and the search for gravity waves became LIGO, the "Laser Interferometer Gravitational-wave Observatory". The 40-meter system Yekta and I bolted together became two systems, one in Louisiana and one in Eastern Washington, each with 4-km arms millions of times more sensitive than what we built in 1981.

This week, the LIGO Scientific Collaboration announced that they have finally detected gravity waves from the collision of two black holes thousands of light-years away. We can't see it happen, but with LIGO we can hear its distant echo. I don't know what happened to Yekta: unfortunately he disappeared to me years ago. I haven't seen my now ex-wife in years, either. But with the announcement that we have heard the echoes of two distant, unseen objects colliding, I am reminded of both.

With a Perspective, I'm Dave Adler.


Dave Adler is a physicist and entrepreneur in San Jose.