The Parker Solar Probe, reaching speeds of 532,000 km/h, is the fastest artificial object, yet it is still very slow compared to celestial bodies in the universe.
Based on current human knowledge, the fastest entities in the universe are photons of light, followed by subatomic particles in particle accelerators or high-energy astronomical events. However, these particles are too small to observe. Instead, the quest to find the fastest object that is large enough to be seen with the naked eye is arguably more interesting, as reported by IFL Science on April 20.
Illustration of a pulsar, one of the fastest rotating objects in the universe. (Image: SA/JPL-Caltech)
The universe is expanding. This means that everything is moving away from each other. The farther an object is, the faster it is receding. Therefore, for humans, the fastest moving object in the universe could also be the one that is farthest away. However, this record is continuously being broken, especially with the advent of new tools like the James Webb Space Telescope. Since its launch last year, the James Webb Telescope has discovered a number of “new contenders” for the title of the most distant galaxy, and there will certainly always be more candidates like this.
However, for any potential inhabitants (if there are any) living in those galaxies, they would not appear to be moving fast at all. They would only see some very distant galaxies moving away, while their own galaxy would seem to be stationary and the nearby galaxies would also be moving very slowly. To simplify, the search for the fastest object that is large enough to see with the naked eye will be limited to those moving fastest relative to nearby objects.
The fastest creation of humanity, the Parker Solar Probe, reaches speeds of 532,000 km/h relative to the Sun and is expected to fly 30% faster if everything goes smoothly. However, this speed is still extremely slow compared to the speeds at which some planets orbit their stars. For example, SWIFT J1756.9-2508b, an object likely to be an exoplanet, orbits its pulsar in less than an hour. This means its average speed is about 766 km per second, approximately 0.2% of the speed of light.
Black holes orbiting each other can achieve much higher speeds, but scientists typically only detect them through gravitational waves after they merge. An exception is two black holes in the galaxy PKS 2131-021. Currently, they take two years to orbit each other, but this process is accelerating.
In terms of linear motion, some stars are ejected from galaxies due to being too close to supernovae or as part of a “three-dimensional gravitational dance.” Among these, the fastest star known to science moves at nearly 1,000 km per second relative to its galaxy.
However, all objects of this type discovered by experts are very far from Earth, meaning they have only observed very large and bright objects. It is possible that fainter stars, or even planets, could also be ejected in this manner and move much faster due to being subject to the same forces while having smaller masses.
Another notable object is PSR J1748-2446ad – a pulsar rotating 716 times per second located in the Terzan 5 globular cluster. This pulsar has an estimated radius of about 16 km. This means its equator is moving at approximately 70,000 km per second, equivalent to 24% of the speed of light, an impressive figure.
