Science in Small Bites
It’s about “Time”
We go about our busy days, occasionally glancing at our watch or the clock on the wall. But we seldom stop to think about how time really works: is it the same time here as on Mars? Is time linear and the same for everyone at all times, throughout the universe?
The following discussion will prove that what most of us think about time is inaccurate.
What began as a thought experiment led Albert Einstein to conclude that “Time is but a persistent illusion.” His statement is fact, but a premise that boggles the mind.
So, what did Einstein mean when he used the word “illusion” regarding time? Not to get ahead of myself, but clearly, he was referring to our brain’s biological inability to conceptualize time in the universal sense.
Time is one of the most used words in any language on Earth. The world would be chaos without time, at least in our world, where our daily lives revolve around a standard way of measuring time.
Without it, we couldn’t organize our schedules or, say, show up for work on time. Time and space are two sides of the same coin – they are intrinsically related, theoretical physicists call it spacetime.
Imagine arranging a lunch date with a friend and not specifying the time or place to meet. You might end up at the Dirt Bean at 11 a.m., and your friend at the Hillsboro Pub at 1 p.m. For both of you to arrive at the same place at the same time, you need to know both sides of the coin, space and time; one is meaningless without the other.
The human brain evolved to accommodate only three dimensions: height, width and length, and, if you include our natural but limited understanding of time, a fourth dimension. Our perception of the malleability of time does not come easily to us. Many reject the notion that time does not pass at the same rate for everyone.
Time, as we know and utilize it, is not universal, nor is it linear. Our view of time is often expressed as a flowing river, but this metaphor is inaccurate.
Time has an inverse relationship with space and is affected by gravity, velocity and entropy. There is an arrow of time pointing toward increasing entropy, beginning after the Big Bang. Entropy, in the context of time, is a measure of disorder. Our universe started with low entropy but continues toward greater disorder; this is one way to think of time.
What we will discuss in the following paragraphs about time is something that can and has been proven many times, but is exceedingly counterintuitive, a real challenge to our natural concept of time. Our brains can easily grasp the idea of linear time, “tick tock, tick tock,” etc., but time is really an expression of velocity, space, gravity and entropy.
Time is not the same throughout the universe, or for that matter, right here on Earth. For example, if you put your wife on a plane from West Virginia to California to visit her sister, upon disembarking at LAX, your wife would have aged slightly more than her sister. Alternatively, when she returns to West Virginia, she will have aged less than you.
You wouldn’t notice this aging because of the lower velocity of the plane, but if that plane could go even a small fraction of the speed of light, 186,000 miles per second, the difference in your ages would be significant. This phenomenon is called time dilation.
The concept of time dilation, however mind-boggling, was proven in 1971 in an experiment that placed cesium-beam atomic clocks on commercial jets and a control cesium-beam atomic clock at a stationary location on Earth. These clocks lose only one second in a million years. Some planes flew east, and some flew west.
As predicted by Einstein, the clocks on the planes either gained or lost time, depending on their altitude and direction of travel, but the results differed from those of a stationary clock, thereby proving the theory of time dilation.
Satellites that provide accurate GPS signals must be routinely recalibrated due to their high speeds and lower gravity in Low-Earth Orbit. Time passes more slowly in satellites than on Earth.
You may have heard of the Twin Paradox, a thought experiment about time dilation. In this experiment, one twin travels near the speed of light in a spaceship, and the other twin remains on Earth. When the space-bound twin returns to Earth, her Earthbound twin has aged considerably more than her.
Where time dilation goes from a thought experiment to reality is in space travel. A trip to Mars and back will be affected by time dilation, though only very slightly. If technology advances to the point where interstellar travel is possible, time dilation would mean that an astronaut would return to Earth far into the future, depending on the spaceship’s velocity.
The previous section was a brief discussion of time, but I urge you to conduct your own research on this fascinating topic. There is a plethora of time-related videos on YouTube featuring physicists that can explain the phenomenon much better than I can.
In parting from the topic of time, allow me to leave you with one more factoid about the subject at hand. The speed of light is the universal speed limit, meaning that nothing can go faster than light at 186,000 miles per second.
Should a future technology exist in which a spaceship with astronauts on board could travel at light speed, time would completely stop for the astronauts without their noticing it, while back on Earth, millions of years would pass. If the spaceship were to travel at a speed close to, but not exceeding, the speed of light, time would slow down significantly, with decades or centuries passing on Earth.
Imagine coming back to Earth, and everyone you knew was long dead, and that’s just how time dilation works. So, the next time you glance at your watch, remember: it may tell you your heart rate and the number of steps you’ve walked, but it’s not telling you the whole story of time.
Now, it’s “time” to move on
“An oak tree is a daily reminder that all great things often have small beginnings.” Matshona Dhliwayo
A friend’s question inspired the following segment of “Science in Small Bites,” “Why are the leaves in the crown of an oak tree different from those lower on the tree?”
The leaves near the top of an oak tree, called the crown leaves, are generally thicker, deeper lobed, and smaller than the shaded leaves below the crown. They evolved to withstand more intense sunlight in the crown.
Likewise, the leaves below the crown are thinner and larger, and the lobes are not as deep as the crown leaves to capture more light, a phenomenon referred to as phenotypic plasticity. The architecture of the stalwart oak is highly efficient, enabling optimal photosynthesis.
Another phenomenon associated with the oak tree is one I find utterly fascinating: the oak apple gall. One tree species we have plenty of here in the Appalachians is the oak family. Every spring, I look forward to seeing the development of these spherical galls, which range in diameter from one-half to two inches and are red or green.
I particularly enjoy showing these galls to visitors as a way of demonstrating how evolution can include a relationship developing between a tree and a very tiny insect, the oak gall wasp, Amphibolips confluenta.
The oak gall wasp injects its egg into a developing oak bud in the early spring. The chemical compounds in the injection begin forming a globular nursery for its larvae. In a very real sense, the tiny wasp is tricking the oak into forming a ball rather than a typical oak leaf.
The unique architecture of the gall positions the wasp egg at the dead center, with structural filaments extending from the photosynthesizing outer layer to provide direct nutrition to the developing larvae. Not to anthropomorphize too much, but this strange relationship between an oak tree and a tiny wasp is quite clever.
I’ve often picked up a gall and wondered how many millions of years it would take for the little wasp to create such a complex relationship with something infinitely larger. It would make sense that the oak gall wasp made the first move. Well, the gall doesn’t do any harm to the tree, so hurrah for the wasp.
Nature is grand and full of mysteries; let’s love it and protect it, so that our grandchildren can pick up a gall and marvel at the beauty of our planet and all of its inhabitants.
In our next episode of “Science in Small Bites,” we’ll ask the probing question, “Can we breathe through our butt?”
Go ahead and laugh, but the answer may shock you.
Ken Springer
ken1949bongo@gmail.com
