I remember fondly watching reruns of Star Trek when I was a kid (I’m not quite old enough to remember them airing for the first time, although we were born in the same year!) and Scotty was always one of my favorite characters. His engineering miracles pulled the Enterprise and her crew out of the fire more often than most. Sometimes it seemed like every other episode, Kirk demanded something of Scotty and the ship that had never been done before, and Scotty never failed to deliver.
Warp speed, Star Trek’s version of faster than light travel, was how the Enterprise zoomed around the galaxy. Star Wars had hyperspace. They folded space in Frank Herbert’s Dune stories. Stargates, wormholes, black holes, and numerous other devices have been used in science fiction to get around nature’s cosmic speed limit: the speed of light.
The speed of light is around 186,000 miles per second. Light moves fast enough to circle the Earth more than seven times a second! Why would anyone need or want to travel faster than that? The unfortunate answer to that is space is mind bogglingly big.
The Earth seems very large to us, sitting on its surface. Yet, when we look around in space, we see that the Earth is quite tiny on the cosmic scale of things. And the distances required to move from planet to planet, or star system to star system, are truly enormous indeed. As I mentioned in the last post, it takes radio transmissions, traveling at the speed of light, about fourteen minutes to reach Curiosity on Mars. And Mars is our closest neighbor!
The distance between stars is measured in terms of lightyears; in other words, the distance light can travel in a full year of time. That’s about six trillion miles. The closest stars which are similar to our sun in size and temperature, are ten to twenty lightyears away. In contrast, the first Earthlike planet which astronomers discovered late last year, orbits a star around 600 lightyears away. Think about that. If aliens on that world had a telescope powerful enough to see us, they would be viewing the Earth as it was 600 years ago. Those aliens might be watching the coronation of Henry V in England! In order to communicate with those imaginary aliens, we would have to wait 1,200 years for a message to make that round trip.
In order for science fiction stories to involve extraterrestrials, the vast majority of them have employed some method to circumvent the lightspeed dilemma. In the book I’m currently working on, I’m using a method involving extra dimensions than the three we’re familiar with, but I think I’ll save that discussion for another post. I do hope someday humans can solve the lightspeed riddle. The universe is so vast and interesting, it would be a shame not to be able to explore it.
Beam me up, Scotty!
Back in the mid-nineties, when we first moved to Montana, the state had no posted speed limit on the Interstate highways. Seriously. The law stated you could drive what was “safe and prudent”. I remember taking my car up to about 97 miles per hour once on a long, straight stretch of road when no one else was around.
I’ve never been much of a daredevil.
What got me thinking about this was Curiosity’s recent landing on Mars. The craft that carried the one-ton rover to the Red Planet left Earth on November 26, 2011. That’s over eight months ago!
At 97 miles per hour, I felt like I was flying. I suppose the car vibrating so much I thought it might shake apart had something to do with my exhilaration. Yet, it’s hard for me to imagine being a professional race car driver, who regularly go twice that fast!
Commercial airliners generally travel around 400 miles per hour. A non-stop flight from Los Angeles to New York City takes about five and a half hours. The same trip took three days, or more, in the time of the Transcontinental Railroad over a hundred years ago. And folks at the time thought that was incredibly fast!
The speed of sound through air is a little less than twice that of the average airliner. While this is very fast, we still understand that sound is not instantaneous. This fact is most evident during a thunderstorm. We see a stroke of lightning, but the sound from that blast of energy doesn’t reach our ears until a few seconds later, depending on how far away the flash occurred. Most of us played the counting game when we were little to see if a storm was moving closer, or farther away, by counting those seconds between flash and rumble.
Our technology is such now that we have vehicles that can travel even faster than sound. Fighter planes and some other aircraft can exceed the sound barrier several times over. The now-decommisioned space shuttles
orbited the Earth at a speed of around 17,500 miles per hour. That means they could make a trip entirely around the Earth in less than an hour and a half. That’s fast! But, once we leave our cozy home, the distances, and speeds necessary to traverse them, become mind boggling.
The Apollo missions that traveled to the moon took close to three days to get there, even moving at an average speed of 2,000 miles per hour. The moon is about 240,000 miles from Earth. In contrast, Mars was approximately 127 million miles from Earth at the time Curiosity launched. The craft was traveling about 13,000 miles per hour when it entered the Martian atmosphere.
Think about that. Moving at that speed, you could make that cross country flight from LA to New York in less than fifteen minutes. Flight time to Mars? Over eight months.
Here’s one more tidbit to ponder. Most of us know and understand that even light, which seems instantaneous to us, travels at a certain speed: approximately 186,000 miles per hour. When the NASA scientists send instructions, moving at lightspeed, to Curiosity, it takes almost fourteen minutes to reach the rover from mission control here on Earth.
Next time, we’ll talk about the cosmic speed limit and if there’s any chance nature might actually have a “safe and prudent” policy like Montana used to, or if we’re stuck with the hard and fast limit of light. Right now, tell me what’s the fastest you’ve ever traveled! How did it feel? Are you a speed demon? Leave your answers in the comments!