Gravity bends light like a cosmic lens
Gravitational lensing, where massive objects bend light, acts as a natural cosmic magnifier, allowing astronomers to see deeper into the universe and study dark matter.
Imagine gravity as a giant magnifying glass in space. This is gravitational lensing, where massive objects like galaxies or black holes warp spacetime, bending and amplifying light from distant sources behind them. Predicted by Einstein in 1915, this effect turns gravity into a natural telescope, revealing faint signals from billions of light-years away. For instance, light from a distant quasar can be split into multiple images or even form stunning "Einstein rings" around a foreground galaxy cluster. This cosmic magnification allows astronomers to peer deeper into the universe, uncovering early galaxies and mapping the mysterious distribution of dark matter, which makes up about 27% of the universe's mass.