Gravitational waves and you.

Mom writes (in regard to the recent detection of tidal distortions of space and time – 'gravitational waves'): "so I told the folks at dinner last night about it - and J [nephew, age 13] insisted this had no meaning for his personal life. What would you have said to his so what?"

J --

Let me first summarize what it was and why scientists think it's important. I'll mention its relevance to your personal life afterward, but my answer is somewhat... open-ended.

What happened

Last September scientists in a group called LIGO detected a stretching in space and time. This stretching was a steady march -- a wave. The piece of the wave that they detected, about 20 of its oscillations, passed through us at the speed of light in around 0.2 seconds. We didn't feel it because it only corresponded to a tiny stretching of space and time – about one part in a thousand-billion-billion.

Similar to a wave that travels through a still pond after you drop a pebble in it, this wave carried a signature of its source. The source was a system of two gravitationally-bound black holes, each initially about 30 times the mass of the sun, orbiting each other closer and closer until they were each moving at half the speed of light. At this point, the masses were in a small enough volume that their impulse to keep spinning was no longer sufficient to keep them from merging into a single black hole. In this process, the black holes shook the sheet of space and time that we live on. Space-time is really stiff, which is why such a violent event only stretched it by a hundredth of an “atom's hair”.

So this happened, and 1.3 billion years later, people in Louisiana and Washington carefully monitored some laser-light and saw it. Paper is here, and a great video explanation is here [5 min].

Scientists think this is important because

(1) it means access to a new source of information about the most extreme (most dense, fastest rotating) objects in the universe and (2) it's only the beginning; these detectors will keep getting better and we will detect many more extreme events. This is important because (3) it means our first direct measurements of new systems (we can't see black holes; they don't shine!), and consequently (4) new regimes to test our understanding of the universe (we know there are some regions, like the centers of black holes, where existing physics breaks down. This measurement actually confirmed part of Einstein's theories we had never tested before). All this is important because (5) it gives us context of who and what we are in the scheme of cosmic history.

So I can tell you that, and then you can say:

"Yeah, but why does it matter for my life?"

Here are some questions that astrophysics and other branches of science get at:

  1. What exists in the universe?
  2. How did it get there?
  3. How did life come from what existed before?
  4. What will the future hold?
  5. How can we keep being a part of it?

These are all very big and poorly defined questions. They matter to my life, and over less than 20 generations of people, we've gone from speculation to measurable facts about many of them. This happened once we admitted our own ignorance and institutionalized ways of creating objectively true stories about reality.

Choose what you allocate meaning to carefully

This tool does not have to matter to you, personally. As far as "how will it affect my life?" I think the right answer is: as much or as little as you want. I remind you that many useful things -- computers, electronics, efficient engines, modern medicine, the internet -- exist only because people pursued objectively true stories about reality. No one knows definitively how this new story will end, or what applications it may generate in the long term.

People choose what they give meaning to. I value being in good health; I value friends and family. I also seriously value objectively true stories about reality. This discovery is an important new one, so it matters for my life.

I leave you to choose how much you want to value such stories. If you're interested, I can point you to a bunch of 'em.

XOXOXO from your cousin, L