2025 RationalWiki 'Oregon Plan' Fundraiser

There is no RationalWiki without you. We are a small non-profit with no staff—we are hundreds of volunteers who document pseudoscience and crankery around the world every day. We will never allow ads because we must remain independent. We cannot rely on big donors with corresponding big agendas. We are not the largest website around, but we believe we play an important role in defending truth and objectivity.

Fighting pseudoscience isn't free.
We are 100% user-supported! Help and donate $5, $10, $20 or whatever you can today with PayPal Logo.png!
Donations so far: $8765.50Goal: $10000

Faster-than-light travel

From RationalWiki
Jump to navigation Jump to search
The facts of the matter
Physics
Physicon.png
May the mass times acceleration be with you
Let's get physical!
Atoms trying to understand atoms
Warning icon orange.svg This page contains too many unsourced statements and needs to be improved.

Faster-than-light travel could use some help. Please research the article's assertions. Whatever is credible should be sourced, and what is not should be removed.

Faster-than-light travel (often abbreviated to FTL) refers to the purported ability or potential to break the universal speed limit of light.

How fast is it, Doc?[edit]

The maximum speed of light is exactly 299,792,458 meters per second (this is possible because the meter is actually defined by the speed of light), but is usually approximated at 3×108 meters per second. Although this is the speed of unstructured light in a vacuum and the speed of light is affected by the material through which it passes,[note 1] the speed of light in a vacuum is the maximum possible speed.

Some claim that this fundamental constant of the universe can be broken or at least worked around. But the amount of energy it takes to accelerate an object with rest mass rises sharply as c is approached until a discontinuity is reached. It would require infinite energy to cross the final gap.

Possibility of travel faster than the speed of light[edit]

Einstein's theory of general relativity does not rule out the existence of shortcuts in spacetime called wormholes which could permit the travel of a ship from one part of the galaxy to the other, bypassing the intervening interstellar space. An extraordinarily advanced civilization could conceivably construct artificial wormholes connecting a group of stars like a subway system. Carl Sagan described such a network in his novel Contact. However, even using wormholes to bypass the speed of light limit opens up possibilities of making "go back in time machines" (unless the science fiction author is very careful in restricting how wormholes can be made).

The Alcubierre drive is another hypothetical possibility. It requires the existence of negative mass. Even if negative masses exist, it would take as much energy as the sun produces over its entire lifetime just to create an Alcubierre warp field, let alone to make such a field move. However, a means of reducing the mass-energy requirements tremendously was theorized by physicist Harold White in 2012.

See also[edit]

Notes[edit]

  1. For example, some particles can travel faster than light can in water, which causes the radioactive glow known as Cherenkov radiation.[1]

References[edit]

  1. Cherenkov Radiation, Explained, Office of Nuclear Energy 28 July 2023