From the October 2014 issue

It’s about time

Is such a concept real or imagined?
By | Published: October 27, 2014 | Last updated on May 18, 2023
New Year’s Eve is when the greatest number of people focus on time. But we astronomers are already more time-dependent than just about anyone. For example, variable-star enthusiasts expect Algol to plummet to its faintest once again on December 15 at 10:22 p.m. EST, distorting the constellation Perseus. Planet observers watch Saturn emerge from behind the Sun every 378 days and see Venus return as the “evening star” every 19½ months. Both are happening now.

This is history’s most optimum period to be time-aware because chronometers have achieved perfection. It started with the balance spring watch, created in 1675 by the same amazing Dutchman who first sketched the Orion Nebula and suggested Saturn’s rings, Christiaan Huygens. Accurate timekeeping further improved after the 1880 discovery that mineral crystals vibrate when zapped with electricity. In 1969, Seiko began marketing watches using such pieces of vibrating quartz. Ancient history. Today you can get “atomic time” on your smartphone.

But just because the quartz in your watch vibrates 32,768 times a second doesn’t prove time is real. You might notice that while an old clock’s pendulum makes 1,800 swings, Earth turns 1/48 of a full rotation and a birthday candle burns down 2 inches (5 centimeters). You could call the elapsing of all these events “a half-hour,” but that still doesn’t mean the time period has some independent reality like a tomato.

The question of time has long tormented philosophers and scientists. Happily, unlike the intricacies of, say, Middle East politics, here we have only two viewpoints. One is the opinion held by such noted smart people as Isaac Newton, who saw time as part of the universe’s structure. He believed it to be inherently real. If so, time essentially constitutes its own dimension and stands separate from events, which unfold sequentially within its matrix. This is probably how most people view time.

The opposing view, argued for centuries by other smart people such as Immanuel Kant, is that time is not an actual entity. It is not a kind of “container” that events “move through.” In this view, there is no flow to time. Rather, it’s a framework devised by humans. If this is true, and time is only a kind of intellectual structure like our numbering systems, then it certainly cannot be “traveled,” nor can it be measured on its own.


The whole business grew much odder with the discovery that some events could start unfolding faster than they had before, relative to others. Einstein’s relativity theories of 1905 and 1915 revealed that even if time is an actual entity, it cannot be a dependable constant like light-speed, gravity, or the mass of the electron. It flows at different rates. Gravity retards the passage of time, as does rapid motion.

We’re intuitively ignorant of this because we all attended a high school where everybody hung out in the same gravitational field. We never, even in our wildest teenage joyride years, accelerated our car faster than an eight-millionth the speed of light. Since it requires 87 percent of light-speed to make time slow by half its normal rate, we’ve never directly experienced time’s fickleness. This is a function of our still-sluggish ground vehicles rather than any personal wisdom.

Think such time distortions are merely academic? Well, we all use GPS. Time signals from the United States’ 24 satellites are how it works. GPS would mess up big-time if continuous compensations weren’t added for various time-warping effects.

Wrinkle one: Satellites travel at high speeds, slowing their clocks. Wrinkle two: They’re away from Earth in a reduced gravitational field, which accelerates their time. Three: Each GPS user sits at various distances from Earth’s center (at, say, Denver’s high altitude), producing a variety of time-passage rates. Four: Time runs slower for all earthly observers because of our planet’s 1,040 mph (1,675 km/h) spin, which itself varies depending on one’s latitude. Five: Satellites’ time passage continuously mutates because their elliptical orbits make them speed up and slow down a la Kepler’s second law. All told, six separate time distortions affect receivers’ clocks; half of these also distort the satellites’ clocks. Without continuous, amazingly clever patches, GPS could never take you home.

And always remember: We’re not talking about the warping of an actual entity called time. We’re noticing only that events unfold at more leisurely rates, or more hurriedly, than they did before, relative to others.

On a distant planet, a hundred years’ worth of events unfolds while a single second elapses for you. Mountains erode on that world while at the same time you kiss someone goodnight.

Worth a moment’s thought, as that falling ball announces midnight — and another year.

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