Tachyon facts for kids

Because a tachyon would always move faster than light, it would not be possible to see it approaching. After a tachyon has passed nearby, we would be able to see two images of it, appearing and departing in opposite directions. The black line is the shock wave of Cherenkov radiation, shown only in one moment of time. This double image effect is most prominent for an observer located directly in the path of a superluminal object (in this example a sphere, shown in grey). The right hand bluish shape is the image formed by the blue-doppler shifted light arriving at the observer—who is located at the apex of the black Cherenkov lines—from the sphere as it approaches. The left-hand reddish image is formed from red-shifted light that leaves the sphere after it passes the observer. Because the object arrives before the light, the observer sees nothing until the sphere starts to pass the observer, after which the image-as-seen-by-the-observer splits into two—one of the arriving sphere (to the right) and one of the departing sphere (to the left).

A tachyon is any hypothetical particle that can travel faster than the speed of light. The concept is an invention of Gerald Feinberg.

Most scientists think that tachyons do not exist. Einstein's theory of special relativity says nothing can accelerate faster than the speed of light, the theory is that these particles would be constantly traveling faster than the speed of light. If a tachyon did exist, it would have an imaginary number as its mass.

Many scientists believe that if one tachyon existed in the universe at any time, then the universe would be overrun by more and more tachyons. This is probably due to the fact that as they slow down, they increase energy. However, some scientists still believe that they could exist if they did not interact with normal matter.

All the particles that go below the speed of light and have mass are known as bradyons.

Curiously, the slower a tachyon moved, the more energy it would have. Therefore, the more energy a tachyon had, the slower it would go, but its speed would never to be equal to or slower than the speed of light.

Possible sightings

It was once thought that neutrinos in experiments at the ATLAS detector in CERN might have moved faster than the speed of light, which was a problem because neutrinos do have a positive, real number mass. This lead to further investigations into more unusual theories of, for example, how particles with normal mass may move faster than light speed, and some claimed that this result would disprove general relativity. However, it was later revealed that the abnormal results were almost certainly the consequence of instrument failure, leading a wide dismissal of tachyonic behaviour in this instance, although some have remained confident that the theories used to explain the faster-than-light case would still be found accurate. Claims that these observations would disprove general relativity, which was reported probably unhelpfully widely in the press, now also seem unlikely.

See also

In Spanish: Taquión para niños