As we gaze at the night sky, imagining the universe as a calm and unhurried place is easy. In reality, however, the cosmos is home to things that move fast. Here are five of the fastest things and events humans have observed in the universe.
1. Cosmic Expansion (Faster than Light)
Scientists agree that the universe is expanding. However, the universe's expansion is not in a way that fills up 'empty space.' Instead, it is 'space' itself that is expanding.
The laws of physics suggest that two objects cannot move faster than the speed of light relative to each other. Still, there is no restriction on expanding the actual space they move in.
In principle, the furthest we can observe in the universe is known as the 'cosmological horizon,' beyond which light cannot yet reach us during the universe's lifetime. Although we can never see it, the cosmos still exists beyond this limit, and the invisible parts of the universe recede from us at a rate more significant than the speed of light. Unfortunately, we can never see those parts of the universe, so we cannot be sure just exactly how fast they are receding.
2. Light (299,792.458 km/s)
Light, or the entire electromagnetic spectrum, is the fastest 'physical' thing in the universe. According to scientists, the speed of light is also the universe's self-imposed speed limit.
Nothing can move faster than the speed of light. This is because objects with mass need energy to accelerate them, and the laws of physics suggest that infinite energy is required to accelerate a mass up to light speed. What is even more confusing is that objects traveling faster than light would have to be traveling backward in time.
3. Gravitational Waves (299,792.458 km/s)
All particles without mass travel at the speed of light, as do the force fields like the weak and strong nuclear forces and the gravitational force. The same goes for gravitational waves, or the ripples in the fabric of space-time created by moving mass.
The first direct detection of gravitational waves was announced in 2016. Since then, the study of these cosmic ripples has helped astronomers increase their understanding of the universe.
4. Cosmic Rays (299,792.4579999 km/s)
Cosmic rays hold the record for ordinary matter traveling at high speed. However, they are not rays but subatomic particles generated in the most powerful events in the universe, such as galaxy mergers and hypernovae, the explosive deaths of extremely big stars.
The fastest cosmic ray yet detected traveled so close to the speed of light that it had the same amount of energy as a medium-paced cricket ball, even though it was a fraction of the size of a single atom.
5. Blazer Jets (299,492.666 km/s)
The speed record for large chunks of matter, as opposed to subatomic particles, is held by the 'jets' observed in 'blazars.' A blazar is a galaxy with an intensely bright central nucleus that contains a supermassive black hole, much like a quasar.
Black holes at the centers of these active galaxies emit vast amounts of energy, which is funneled into jets by a dense, highly magnetic accretion disk. Jets observed so far move at about 99.99% of the speed of light.
RELATED ARTICLE : What Is the Speed of Gravity? Do Gravitational Waves Travel Exactly at the Speed of Light?
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