Soumendra Nath Thakur
ORCiD:0000-0003-1871-7803
16-10-2924
Dark energy exerts a repulsive, anti-gravitational force that drives the acceleration of galaxies away from each other, particularly on intergalactic scales. While gravity pulls galaxies together within their own local systems, dark energy pushes galaxies apart, increasing the distance between them. As this repulsive force grows, galaxies recede from one another at ever-increasing speeds, leading to the observation that distant galaxies appear to move faster than the speed of light. This recession results in the redshift of light from these galaxies, a direct consequence of dark energy's anti-gravitational effects. Over time, more galaxies will pass beyond a cosmological event horizon, making their light inaccessible to observers on Earth.
Explanation of Faster-than-Light Speeds:
The speed of light (c) is a strict limit only within gravitationally bound systems, such as inside galaxies or galaxy clusters where gravitational forces dominate. However, much of the universe, particularly on the largest scales, is not gravitationally bound. In these vast intergalactic spaces where dark energy predominates, the anti-gravitational effects take over. In such regions, the limitation of light speed does not apply in the same way, as the motion of galaxies is governed by the repulsive force of dark energy rather than the gravitational influence of nearby objects. This allows the apparent recession of distant galaxies to exceed the speed of light. However, within these receding galaxies themselves, gravitational binding still holds, and the local speed limit remains governed by the speed of light.
Reference:
Chernin, A. D., Bisnovatyi-Kogan, G. S., Teerikorpi, P., Valtonen, M. J., Byrd, G. G., & Merafina, M. (2013). Dark energy and the structure of the Coma cluster of galaxies. Astronomy and Astrophysics, 553, A101. https://doi.org/10.1051/0004-6361/201220781
Its a fascinating article on cosmology!
This article summarized the concept of distant galaxies moving faster than the speed of light, which seems counterintuitive at first. However, as explained, this phenomenon is due to the repulsive force of dark energy dominating on large intergalactic scales.
Key points:
The reference provided supports this understanding, highlighting dark energy's influence on galaxy structures.
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