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by Larry

February, 2016

Weighty Ripples in Spacetime

Roughly 1.3 billion years ago, all life on this little planet was rather basic: just single cells. Multicellular species would not evolve for another 700 million years. Later still, there were the differentiations into plants, animals, or funguses. Small, primitive mammals did not come along till the last 150 million years or so.

Gravity Probe B circling earth, measuring spacetime (NASA artist conception)
Yet, as if they had created a time machine for seeing that far back, last year scientists detected the collision of two massive black holes 1.3 billion years ago using a pair of complex identical instruments, one in LA, the other in WA State, together called the Laser Interferometer Gravitational Wave Observatory (LIGO). As I understand it, LIGO involves a couple L-shaped antennae set up to show perfect alignment of lasers reflecting between mirrors. If the mirrored light is even slightly out of alignment, this is recorded and the cause can be deduced. In this event, the first detector showed a misalignment in precisely the tiny amount and brief length of time predicted by the effect of passing gravity waves from the 1.3 billion light years distant black holes' impact, and, at exactly the proper interval after such detection at the LIGO installation in LA, the same out of alignment event occurred at the second detector, in WA.

The 1.3 billion years ago momentous collision of these dark phenomena occurred at half the speed of light, in miles per hour too high a figure to write here with ones and zeroes. It was noted first at the Livingston, LA, detector and then, a tiny fraction of a second later, in the more northerly one, at Hanford, WA, since it was a bit farther away. For around four months the data on the pair of detections was analyzed. Since awhile previously there had been a false alarm from a different scientific facility, on this occasion scientists wanted to be certain before any announcement. Firm and affirming conclusions were finally drawn. Only a few days ago, on February 11, 2016, the official word: humans had for the first time successfully recorded the presence of gravity waves, ripples in the fabric of spacetime such as Einstein's theories a century earlier had predicted would exist. The waves had been generated by the cataclysmic merging of the two distant black holes. This breakthrough is the most direct yet confirmation of the gravity waves Einstein forecast to be found. Additionally, it is further verification of the existence of black holes.

Besides the confirmations noted above, this initial success of LIGO has other implications:

  1. Gradually greater refinements of gravity wave detection promise eventually a new way of studying the universe. Just as astronomers are no longer limited to using visible light for detecting and researching far off phenomena in the cosmos, but can do so as well with radio waves, etc., so now gravity waves may give us clues about the nature of reality. Gravity waves or ripples in the fabric of spacetime must be given off by all sorts of occurrences, and their measurement will reveal the universe in unforeseen ways.

  2. Some of the findings will no doubt be so different from what is now understood about reality as to call for major revisions in our perspectives. But a few generations ago, nobody knew that there were other galaxies besides the Milky Way. Finding out later that there are in fact billions of them was shattering to the prior outlooks. Given that we now know that the physical matter stuff of which we are made is but a fraction of what is out there, that dark matter and dark energy comprise the vast majority of existence, yet we do not understand what either of these things are, it is clear astronomers and physicists have yet much more to learn. Some of this new, potentially mind-blowing data may come from future LIGO or LIGO-like instruments and events.

  3. Cosmologists believe that the ultimate mystery of the universe and how it became just the way it appears now is in how it commenced in the first few fractions of a fraction of a fraction of a second. Gravity waves may someday also be able to provide more information about its earliest possible origins from an almost infinitely small singularity about 13.8 billion years ago.

  4. Such additional info may also help physicists unite the two main theories of reality, quantum mechanics (including the strong and weak forces plus electromagnetism), which tells us of interactions at the level of the very small, and General Relativity (as it applies to gravity), which tells of interactions on the scale of the very large. Einstein believed a complete theory of everything should be possible, one that combines these two great theories into one comprehensive description of how absolutely all that is works together and why. If there are quanta behind what we experience as gravity, they might be confirmed and their characteristics ascertained using a later type of gravity wave detector, leading hopefully to a union of the known kinds of force into one fundamental understanding.

  5. If there is intelligent life elsewhere, it is just possible it is attempting to communicate. Highly developed other species may have been around for hundreds of thousands or millions of years and be far beyond our own kind, which of course has seen at best a few thousand years of scientific innovation. Light in its various visible and invisible frequencies has its own limitations as a means of transmitting data. For one thing, it is easily absorbed along the way. Yet if such advanced beings exist, they might be able to use other means, including subtle forms of gravity waves, to get in touch. One day a future version of The Search for Extraterrestrial Intelligence (SETI) may decipher a gravity wave "g-mail" with far reaching, yet unpredictable significance.

Of course, nobody knows why the universe itself came into being. Ultimately, that is the domain of religious teachings and of philosophers. Yet bright markers along the still dim path toward genuine understanding of reality are being laid down, and the latest of these are the LIGO findings publicized this month.

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