Philosophy and time

In our every-day world, we experience space as three dimensions—high and low, right and left, thick and thin. Time acts like a fourth dimension. We can go any direction in space—in theory, we can travel an infinite distance in any direction. Time is different—we move only one direction, and we all travel at the same speed as we journey out of the past, through that instant that is the present, and on into the future.

Things are never as simple as they seem. We live on the surface of a sphere, and up and down are defined for us by our relationship to the sphere. If we tunnel down, we might eventually reach the center of the sphere. Traveling further, we would be going up again until we reached the surface of the sphere on the far side. On the other hand, traveling up would send us away from the sphere, but if each of us traveled up away from the sphere, we would all be going different directions away from the sphere, getting farther and farther from one another.

If we travel north or south on the surface of the sphere, we eventually reach a pole. We could go no further north; we could only go south from the North Pole—and the same would be true of the South Pole. East and west, though, are infinite journeys. No matter how far east we travel, more east lies beyond us; no matter how far west we travel, more west lies beyond us. We could circle the Earth many times and still never come to the end of east or of west.

Albert Einstein’s theories of relativity acknowledge the three familiar dimensions of space and the single dimension of time, but Relativity also reveals that all four dimensions change when we deal with the very large, the very small, and the very fast. A traveler moving near the speed of light would experience less time than a similar traveler on the Earth—even if they were born on the same day, after journeying at the speed of light, the first traveler would be younger than the second. Curvature of the fabric of space and time, according to Relativity, account for gravity, which is why during a solar eclipse astronomers can view stars that lie behind the sun. Other strange things happen in space and time according to the theories of relativity—and every test devised to determine whether Relativity is accurate have affirmed Einstein’s theories. For our daily lives, though, the geometry of Euclid and the physical laws of Isaac Newton suffice. Variations from those systems only happen in extreme cases such as galactic events and subatomic physics.

Often we represent time as a line. We mark events on that line, showing which are earlier and which are later. We locate births and deaths on that line to show how long each person has lived. Changes in the universe happen in only one direction and are not easily reversed. If one pours a class of colored water into a tank of clear water, the colored water gradually mixes with the rest of the water until it all has the same hue. This change requires considerable effort to reverse, to remove the color from the water. This tendency of thing to even out over time is called “entropy,” and entropy indicates a direction in time, the direction we all are traveling.

When I was younger, people frequently rode in the back of pick-up trucks. We had no seat belts; our safety depended upon the skill of the driver and upon chance. We accepted the risk, trusting the driver and assuming that nothing would occur that he or she could not handle. Imagine yourself sitting in the back of a truck, looking at the road you have just traveled. You see what is behind you; you cannot see what lies ahead. Some parts of the past journey are clearer than others, just as we remember some past events better than we remember others.

Looking right and left, we can see landscape, places we have not visited. We might see roads we have already passed, roads that would take a vehicle to other places. If the road we are traveling is a single dimension of time, those other roads and other places might be another dimension. We could call that dimension “imaginary time.” This imaginary time contains all the “what-if” possibilities of our lives. Some people speak of imaginary time as if it was real, as if it existed in alternate universes. What if Nixon had won the 1960 election against Kennedy? Or what if Kennedy had not been killed in 1963? What if I had taken different classes in college and graduated with a different major? What if I had accepted that job offer ten years ago and moved then to a different city? We can guess about different events and different time lines, but we remain on the same time line we each have been traveling since birth.

Or do we? Some people claim to remember different time lines—a world where Nelson Mandela died in the 1980s and not 2013, a world in which the children’s authors spelled their name “Berenstein” and not “Berenstain,” a world in which New Zealand is to the west of the Australia and not to the east. Most of us assume that human memory is fallible—that we might misremember facts like those, or lines from a movie or a song, or the appearance of a cartoon character. That does not prevent our minds from pondering what might happen if we could journey off our timelines and explore imaginary time. Sometimes imaginary time is useful. If the dog slipped outdoors when we weren’t looking, it might have run any direction. We consider how much time has passed since the dog escaped and estimate how far it might have gone; that helps us to think of places to search for the missing dog.

Time feels relative. Some minutes drag on at excruciating length while others pass by far too quickly. Some past events feel far more recent than they truly are, while other past events seem far more distant than they really are. The week before Christmas can be far too short with people who need to prepare and far too long for people eagerly anticipating the holiday. We are traveling the same timeline, but we do not experience it in the same way.

 But what if we could view our lines in time from an entirely different perspective? J.

The dream of landing a man on the moon

When Neil Armstrong and “Buzz” Aldrin walked on the moon fifty-one years ago, it appeared that the world was beginning a new Space Age. Several more teams of American astronauts returned to the moon—one team, Apollo 13, suffered from technical difficulties and had to return without landing on the moon—but since that time, the space program has not advanced as expected. Space stations were formed, and shuttle missions were launched. Computerized machines were sent all over the solar system to record information and report back to Earth. But the science fiction stories that seemed ready to change from fiction to fact did not come true. Colonies were not living on the moon by 2001. No one has gone to Mars or to any other planet. Space stations remained tiny capsules orbiting the Earth—no vast city in space has been developed to launch travelers to the moon or Mars or any other destination out there in space.

Why has space exploration faltered since the grand successes of the Apollo missions to the moon? Noble talk of exploration being worth any cost and any risk has not led to glorious deeds. Explosive growth in computer technology has been devoted almost entirely to earth-bound endeavors, especially in the areas of communication and entertainment. Competitive juices of the Cold War no longer fuel programs to open new frontiers and to go where no one has gone before. Our dreams may be as big as ever, but our investment in those dreams has dwindled.

In the 1960s, Dick Tracy communicated to headquarters with his watch and Maxwell Smart kept in radio contact through his shoe. Now most of us carry or wear devices that facilitate communication, take pictures and videos, allow access to libraries of digitized information, and permit us to play games any time and any place. Our cars cannot fly, but we can start them from inside the house and have the heat or air conditioning running while we finish getting ready to leave. We know where we are and how to get where we want to go with exact precision—precision that everyone from government agencies to advertisers can use to keep track of us all the time and to know what topics we are researching and what questions we want answered. We can buy and sell at the click of a button, and our financial information is available to us (and to many other people) any time and any place.

Our hunger for space travel was fed, not by the Apollo missions and the space shuttle, but by the Star Wars franchise and its many companion stories. Faster-than-light travel is no more possible now than when Gene Roddenberry imagined warp engines for the Enterprise. Time travel is still limited to one day at a time into the future. Meanwhile, nature has not yet been conquered on this planet: it can still hit us with a storm or an earthquake or a plague, seemingly at will.

This is the future, or at least it was the future when Neil Armstrong recited, “That’s one small step for [a] man; one giant leap for mankind.” What now remains in our future remains to be seen. We will face more challenges; we will encounter more adventures. New technology will surprise our children as new technology surprised our parents. The tools we use today will amuse museum visitors fifty years from now. No one can guess when the human spirit will rise again to look at the stars, to explore new frontiers, or to solve the problems that stymie us today. So long as there is a future, though, we still have a chance to dream. J.