Gravitational lensing in MACS J1149-2223

This animation shows the effect of strong gravitational lensing, which can also be seen in the galaxy MACS J1149-2223. The mass of the galaxy cluster bends and magnifies the light of more distant objects in the background, making them appear brighter and hence allows telescopes to see them; it also leads to multiple images of the same object. This way Hubble detected the most distant star know to date, called LS1.