From the July 2008 issue

If photons have no mass, how can gravity bend light?

Matt Francis, Kamas, Utah
By | Published: July 3, 2008 | Last updated on May 18, 2023
According to Albert Einstein’s theory of general relativity, published in 1915, gravity is equivalent to the curvature of space. Thus, any particle — no matter what its mass — travels in a distorted path as it passes by a massive body such as the Sun. But Einstein wasn’t the first to notice this.