It has been agreed upon that the fastest 'physical' thing in the universe is light itself, or the entire electromagnetic spectrum. So far, nothing has been found to move faster than 299,792.458 kilometers per second. A pair of physicists, however, has discovered that the cosmos may be dominated by particles which move faster than the speed of light.
New Model of the Universe
In a new study, scientists Samuel H. Kramer and Ian H. Redmount proposed the idea that the universe is dominated by tachyons. The details of their study are described in the paper "Testing Tachyon-Dominated Cosmology with Type Ia Supernovae."
Tachyons are a hypothetical kind of particle which always travel faster than light. These particles almost certainly do not exist, and moving faster than light violates everything we know about the causal flow of time from past to future. Still, they are particularly interesting to astronomers due to the small chance that even our most closely held notions, like causality, might actually be wrong.
Kramer and Redmount suggest that tachyons might be the true identity of dark matter, the elusive form of matter which makes up most of the mass of almost every galaxy in the cosmos. Although dark matter outweighs normal matter, astronomers are still clueless about what dark matter is made of.
The pair of researchers calculate that an expanding universe filled with tachyons can initially slow down in its expansion before reaccelerating. Currently, our universe is an accelerating stage, driven by a phenomenon called dark energy. This is why the tachyon cosmological model has the potential to explain both dark energy and dark matter at the same time.
To test their idea, the physicists applied their model to observations of Type Ia supernovae, a type of stellar explosions which enables cosmologists to establish a relationship between distance and the expansion rate of the cosmos. Because of the discovery of Type Ia supernovae, astronomers in the late 1990s first identified the accelerating expansion rate of the universe.
Kramer and Redmount found that a tachyon cosmological model was just as good at explaining the supernova data as the standard cosmological model that involves dark energy and dark matter. This is a surprise, given how unorthodox the idea is.
Still, this is just the beginning. Astronomers currently have access to a wealth of data regarding the large-scale universe, such as the cosmic microwave background and the arrangement of galaxies at the very largest scales. The next step is to continue testing this idea against the additional observations.
What is Causality?
Causality refers to a genetic connection of phenomenon through which one thing under certain conditions gives rise to something else. Its essence is the generation and determination of one phenomenon by another. All certainty in our relationship with the world rests on acknowledgement of causality.
Causality is universal, which means that nowhere in the world can there be any phenomena which do not give rise to certain consequences and have not been caused by other phenomena. Our universe is a world of cause and effect whose connection takes place in time.
The existence of causality between events is a consequence of the existence of the limiting speed of transmission of interactions in the cosmos. With the use of a single four-dimensional space-time continuum, it is shown that causality is a vital characteristic of our universe.
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