Most readers will have grown up with science fiction TV shows such as Star Trek and movies like Star Wars, in which interstellar travel is commonplace and apparently simple. We live in the Steven Spielberg generation, in which science fiction concepts are accepted as reality or at least seem probable. But while present-day science is making advances in these areas, we’re still a long way from even sending manned spacecraft to other planets within our own local Solar System. The fastest space vehicle launched from Earth to date will take thousands of years to reach the distance of even the nearest star.
The first spacecraft to leave our Solar System was Pioneer 10. It was launched in 1972 and reached the orbit of Jupiter in 1973, after which it continued on, but stopped transmitting signals to Earth in 2003 when its power source stopped functioning. It is heading in the direction of the constellation Taurus and will pass close to the star Aldebaran in about two million years.
DID YOU KNOW?
The belief
that life exists elsewhere in the universe
can be traced back to the Greek philosopher Anaxagoras, who
in the fifth century B.C. wrote that the universe is teeming with life.
He coined the term panspermia, which literally means “seeds of life everywhere.”
Pioneer 10’s twin is Pioneer 11. It made a flyby of Saturn in 1979 and is heading in a different direction, this time for the constellation Aquila. It will reach it in about four million years. Both Pioneer 10 and Pioneer 11 had plaques attached to their sides upon which was inscribed a message to anyone or anything that might find the spacecraft some day. The plaques have pictures of a man and a woman, the Pioneer spacecraft, and instructions on how to find Earth based on navigating between pulsars in our galaxy.
Two spacecraft that were launched after the Pioneers but which will reach nearby stars sooner are Voyager 1 and Voyager 2. The first also went by Jupiter and is heading towards the constellation Camelopardalis, which it will reach in 300,000 years. Its twin, Voyager 2, is going in the direction of Sirius, the Dog Star, and will get there in “only” 150,000 years.
The fastest moving of these four spacecraft is Voyager 1, which is travelling at about 63,000 kilometres per hour. If you could drive a car that fast, you could go around the entire Earth in 45 minutes, assuming that someone built a road around the equator.
Despite what may seem to be a pessimistic view of travel times in outer space, it’s theoretically possible for us to build spacecraft today that could reach a planet orbiting a nearby star within the lifetime of an astronaut on board. Einstein showed that a spacecraft moving fast enough would have time slow down on board the spacecraft while to an observer, on Earth, time would pass normally and it would seem that the spaceship was gone a very long time, perhaps many decades. To the astronaut, time would move more quickly and he or she would age at a much slower rate, reaching the destination in only a relative handful of years.
This is still a long way from “Warp Factor Three,” but it shows that space travel is possible even with our present technology. But here’s the single fact that could change science fiction into science fact: not all stars are the same.
The Milky Way has about 100 billion stars. Some are hotter than our Sun; some are cooler than our Sun. Some are larger; some are smaller. Some are younger; some are older. In fact, some are much older — even billions of years older. What this means is that some stars with planets that can support life have had much longer to nurture and advance the life into highly evolved and technological civilizations. It is reasonable to think that some of these civilizations may have advanced so far technologically that they have discovered a way to travel between the stars like in the TV show Star Trek or at least have lifetimes that allow long journeys between stars. Maybe they have found ways to use sleep chambers to prevent aging on long voyages.
At any rate, the possibility that some alien civilizations are much more advanced than us is very good. If so, perhaps they have visited the Earth during our history or are doing so now. Just because we have no incontrovertible evidence they are doing so is not proof they are not doing so.
By definition, aliens will think and act in alien ways, beyond our comprehension and understanding. Maybe we simply cannot detect their existence because of some peculiar characteristic of their spacecraft.
There is a great deal of modern scientific research and brilliant deductive studies in the emerging field of exobiology: life outside of the Earth. Hardly a month goes by without more analyses being completed on another sample of Martian soil or rock in a quest for evidence of extraterrestrial organisms. The duplication of amino acid formation in the early stages of Earth’s history has convinced many scientists that life would likely arise on other planets and produce creatures somewhat similar to ourselves.
We know with a high degree of certainty that other human-like creatures do not exist elsewhere in our Solar System. Speculation is rampant that primitive lichens and bacteria may exist on Mars, in Venus’ atmosphere or perhaps even on a large moon of Jupiter or Saturn. Regardless, our local star system has been more or less eliminated for extraterrestrial life, based on our knowledge of what conditions are necessary for life to be viable, such as heat, light, water, etc. Where else might it occur?
UFOS AND ALIENS IN LITERATURE
The term Martian conjures up images of bug-eyed monsters, many-tentacled monsters and evil aliens, all intent on doing us in, but also a black-headed cartoon character who battled Bugs Bunny in several shorts and features. As well, Edgar Rice Burroughs, creator of Tarzan, wrote a series of space romance novels in the early 1900s in which American John Carter travelled to Mars only and battled many strange creatures, often necessary to rescue maidens in distress.
On a clear night, you can see only about 5,000 of the billions of stars in the universe. The rest are too far away and their light is too dim to be seen by us here on Earth. Some of these stars are physically very close to us and can be called our neighbours, even though they are still trillions of kilometres away!
The nearest star system to us is the Centauri triplet of stars right next door, only 40,621,000,000,000 kilometres away! That’s about 4.3 light years in astronomical terms; it takes light waves more than four years just to reach us from those stars.
The nearest of all other stars is Proxima Centauri. It’s a dim, red star that orbits the pair of stars known as Alpha Centauri A and Alpha Centauri B. These three stars perform a kind of cosmic waltz with one another, with Proxima dancing by itself while revolving around the two others of the trio. Proxima is about 4.2 light years from us, while its companions are 4.3 light years away. Alpha Centauri A is the same colour as our Sun, which means it is about the same temperature as the Sun. All things being equal, it might be able to support planets like Earth and sustain life.
WHAT IS A LIGHT YEAR?
Distances in space are measured not in miles or kilometres, but in light years. One light year is the distance that light travels in one year. Although light seems instantaneous, it actually takes time for it to travel great distances. The speed of light is 300,000 kilometres per second.
For example, since the Moon is about 376,000 kilometres away from the Earth, light takes a little over one second to travel between the Earth and Moon. The sun is much farther away, and light takes about eight minutes to reach us from its surface. But other stars and galaxies are much farther away, and light takes many years to travel that far.
However, with three stars orbiting around one another, the mechanics