Communication Help (page 3)

By — McGraw-Hill Professional
Updated on Sep 17, 2011

A New Kind Of Patience

Regardless of the mode, be it radio signals, infrared, visible light, or some thus-far-unknown technology, Homo sapiens will have to cultivate great patience to make interstellar communications possible. We will have to be willing to send out signals and realize that they might not be heard until many human generations have come and gone. It is difficult to imagine putting down notes that we do not expect will be read for 50,000 years. But there is no way, as far as anyone knows, that our descendants 500 centuries from now, reading our instructions and adjusting their communications equipment accordingly, can reply to us and ask, “What if your software doesn’t run on our computers?”

It is hard enough right now, in most Earthly societies, for parents to communicate with their children. Imagine this generation gap multiplied by several thousand times! If ever a civilization from some distant star system sends its representatives to meet us here on our humble little planet, we will know that they have attained a degree of patience we can only dream about. However, it will inspire us, because the instant we know who they are and where they came from, we will realize that if they can attain such a lofty state of existence, so can we. We will realize that Earth is not a miracle. Or if you prefer, we will come to know that miracles are common in the Cosmos.


Communication is an economical way to search for life on other worlds, and it is also the method that we can expect to produce results, if there’s anyone out there listening and transmitting with the same intentions. However, communication is not much of an adventure, and if we ever find another civilization “on the radio,” we’ll want to meet those beings face to face. This can happen in three ways: We can go to them, they can come to us, or we’ll run across each other in the vastness of interstellar space.

We Do The Traveling

Interplanetary travel, within the limits of our own Solar System, has already been done by robotic space probes. We know it’s possible for machines to do it, and given reasonably good economic and political conditions in the next several decades, astronauts will someday visit some of the planets and moons, especially the planet Mars and Saturn’s largest moon, Titan. It is not necessary to attain fantastic speeds to get to the other planets in our Sun’s family. To reach the stars, however, we will have to accelerate our space ships almost to the speed of light.

If the Earth were the size of a marble, the Moon would be a small pea approximately 300 mm (about 1 ft) away. At present space-ship speeds, it takes 2 or 3 days to get to the Moon. On this same scale, the Sun would be about 120 m (or 400 ft) away, roughly the distance from home plate to the center-field fence in a major league baseball stadium. The distance from the Sun to Pluto would be on the order of 5 km (3 mi). We have the ability to span these distances, although it takes years to reach the outermost planets. The nearest star to our Solar System, Proxima Centauri , would be more than 32,000 km (20,000 mi) away on this same scale. Even if we can build a ship that will travel at half the speed of light, a round trip to this star will take 18 years. Our Milky Way galaxy is 25,000 times wider than the distance to Proxima Centauri.

If we humans are ever to attempt interstellar travel on a galactic scale, our space vessels will have to reach speeds so high that a peculiar phenomenon, relativistic time dilation , takes place. Maybe you’ve heard about this: the slowing down of time for beings in a vessel traveling at near the speed of light. This would make it possible, in theory, to reach almost anywhere in the known Universe within the span of one human lifetime. Relative to the rest of the Cosmos, however, including the planet of origin (Earth), such space travelers would be hurled irrevocably into the future by hundreds, thousands, or millions of years.

Long-distance space travel presents all kinds of obstacles and dangers, and we’ll look more closely at this subject later in this book. We’ll study relativistic time dilation and other effects of extreme speed as well.

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