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How did general relativity explain the shifting perihelion of Mercury?

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gravitational lens — gravity A galactic cluster, about five billion light-years away, produces a tremendous gravitational field that “bends” light around it. This lens produces multiple copies of a blue galaxy about twice as distant. Four images are visible in a circle surrounding the lens; a fifth is visible near the center of the picture, which was taken by the Hubble Space Telescope.

In Newtonian physics, the orbit of Mercury is expected to be a stable ellipse, with its perihelion (the point closest to the Sun) shifting only due to the gravitational influence of other planets. However, astronomers observed an unexplained discrepancy: the perihelion was advancing by 43 arc seconds per century more than Newtonian theory could account for.123

In 1915, Albert Einstein resolved this issue with his general theory of relativity. Rather than treating gravity as a force acting across space, Einstein described it as the curvature of space-time caused by mass. He demonstrated that for massive bodies in close proximity, Newton’s law of gravitation requires a correction term that accounts for this curvature.451

When applied to Mercury, this relativistic correction precisely predicted the observed 43-arc-second-per-century shift in the planet's perihelion. This success provided a critical observational verification of general relativity, confirming that gravity is a manifestation of the geometry of the universe rather than a simple Newtonian force.23145