The 32,000–word novella The Time Machine by H.G. Wells, published in 1895, is generally credited with popularizing the idea of time travel by means of a time machine, a vehicle which takes the occupant backward or forward in time. Dozens of sequels and adaptations over the years have further promoted the notion. Indeed, Albert Einstein’s Theory of
Special Relativity lays the foundation for the possibility of time travel. So far, no one has demonstrated the ability to travel in time. However, time machines have been constructed, and they do allow glimpses into the past.
The most efficacious time machine currently in existence is the Hubble Telescope, named after the American astronomer Edwin P. Hubble. Its capability to locate distant astronomical targets and lock in on them, permitting their faint light to aggregate on its detectors, allows it to
peer far into the past. Light travels 186,000 miles per second. The Hubble Telescope has looked back in time at 10,000 galaxies whose light left them billions of years ago. Therefore, utilizing the telescope as time machine, astronomers are able to contemplate galaxies as they were eons ago.
Although the telescope was launched into space in 1990, its inception was almost a half century earlier as astronomer Lyman Spitzer, Jr. mulled over the possibility of a large space telescope in a 1946 report, “Astronomical Advantages of an Extra–Terrestrial Observatory.”
Because the earth is bathed in its constantly churning atmosphere, earth–based telescopes cannot penetrate deep space; the atmosphere distorts the view. Telescopes were constructed on mountains, but there was still no way to wholly escape the effects of the layers of gases
enveloping the earth.
During the 1960s, the Space Race between the then–Soviet Union and the United States was accelerating. The National Aeronautics and Space Administration (NASA) was established.
Funds for space endeavors were abundant, and plans for a large space telescope, by then designated the LST, were underway. The designs called for a 2.4–meter primary telescope mirror which could be transported into space by one of NASA’s rockets. According to National Geographic’s Imaging Space and Time, the resolving power of the deep space telescope would be “equivalent to being able to distinguish the left and right headlights of a car in California seen from New York, or features less than 1/30,000 the size of the full moon. This was at least a tenfold increase over the atmospheric limit.”
One of the primary challenges involved in successfully transporting the telescope into space was protecting the mirror from the jarring vibrations that occur during launch. It was crucial that the mirror be able to withstand the shuttle’s vicissitudes as well as the volatile atmospheric conditions found in space. If not, the precise shape of the mirror could be
compromised, and its imaging capability significantly weakened.
After the telescope had been launched, astronomers subsequently realized that the primary mirror had not been ground correctly. A lens in the test instrument was about one millimeter askew, which is large by optical standards. In 1993, space–walking astronauts installed corrective lenses which improved the eyesight of the Hubble. In 2009, the corrective
lenses themselves were replaced with a super sensitive spectrograph with built–in corrective lenses. The new spectrograph is expected to provide insight into the origins of stars and galaxies.
The successor to Hubble, the James Webb Space Telescope, is expected to be launched in 2014. It will observe only in infrared, so it will complement the Hubble Telescope, which observes in the visible and ultraviolet light ranges.
Hubble currently has the capability to view galaxies that were formed 13.7 billion years ago, long before humans existed, in an area called the Hubble Ultra Deep Field. Astronomers aspire to see beyond the Hubble Ultra Deep Field to a time that is devoid of galaxies, a time before galaxies had formed.
If H.G. Wells was onto something in his novella, that time may be close at hand. As one of the characters in the popular work asked, “If Time is really only a fourth dimension of Space, why is it, and why has it always been, regarded as something different? And why cannot we move in Time as we move about in the other dimensions of Space?” Less than a decade after Wells’ novella, Einstein’s Special Theory Relativity seemed to concur with Wells’ character by proposing that traveling through space at the speed of light would alter time by causing it to dilate, raising the possibility of not merely glimpsing the past,
but perhaps traveling to it.