186,282 miles per second

speed of light

Radio Waves

What distinguishes these different bands of light is their frequency (or wavelength). But what they all have in common is that they travel at the same speed in vacuum. The reason for qualifying ‘in vacuum’ is because EM waves of different frequencies often propagate at different speeds through material.

Light, no matter how high-or-low in energy, always moves at the speed of light, so long as it’s traveling through the vacuum of empty space. By passing that light into a non-vacuum medium, you can change its speed so long as it’s in that medium.

The speed of light is normally about 186,000 miles per second, or fast enough to go around the world seven times in the wink of eye. Scientists succeeded in slowing it down to 38 mph. They did this by shooting a laser through extremely cold sodium atoms, which worked like “optical molasses” to slow the light down.

Light travels forever until it is absorbed. However, if it travels a very long way indeed, it is redshifted by the expansion of the universe. According to flat Earthers, the light will fade after only a few thousand miles…

Nothing can move faster than the speed of light. Through a medium of any type — whether that’s air, water, glass, acrylic, or any gas, liquid, or solid — light travels at a measurably slower speed. Energetic particles, on the other hand, are only bound to travel slower than light in a vacuum, not light in a medium.

So will it ever be possible for us to travel at light speed? Based on our current understanding of physics and the limits of the natural world, the answer, sadly, is no. So, light-speed travel and faster-than-light travel are physical impossibilities, especially for anything with mass, such as spacecraft and humans.

44.72km/h

racer Srinivas Gowda

sprinter Usain Bolt

If you can hold it for a marathon (42,2km), you can run a 1hr 26 min marathon. The mile, 1/4mile, and 100m times are all impressively fast and physiologically possible. The marathon time is completely unrealistic. I would say 17 miles per hour is very fast (way above average) for any age group.

Average speed – indications Most cyclists can achieve 10-12 mph average very quickly with limited training. Reasonable experience, medium (say 40 miles): average around 16-19 mph. Quite competent club rider, some regular training likely, medium-long distances (say 50-60 miles): 20-24 mph.

But, by most standards, running at 12 mph isn’t all that fast. It means an average of a 1:15 for a quarter mile, which is really the longest sprint (maybe 800 can be considered a sprint). 37.5 for a 200.

According to dog expert Stanley Coren, “When Usain Bolt set his 100 meter world record he was running at a speed of 22.9 mph and covered that distance in 9.58 seconds. A greyhound would complete that same race in 5.33 seconds.” A greyhound could beat Usain Bolt’s 100 meter world record in 5.33 seconds.

Bolt ran 200 meters in 19.19 seconds, while a cheetah could sprint that distance in 6.9 seconds, a Black Caviar racehorse would gallop the same in 9.98 seconds, and a greyhound in 11.2 seconds.

Elite human runners, however, can sustain speeds up to 6.5 meters per second. Even run-of-the-mill joggers typically do between 3.2 and 4.2 meters per second, which means they can outrun dogs at distances greater than two kilometers.

Check out the top ten smartest dog breeds.

• Border Collie.
• Poodle.
• German Shepherd Dog.
• Golden Retriever.
• Doberman Pinscher.
• Shetland Sheepdog.
• Labrador Retriever.
• Papillon.