Abell 2744 and three images of a distant galaxy
This is a NASA/ESA Hubble Space Telescope image of the huge galaxy cluster Abell 2744, taken using the Wide Field Camera 3 and Advanced Camera for Surveys.
The three annotated areas show three images of a single, very distant, galaxy whose light has taken 13 billion years to reach us. The galaxy has been magnified and multiplied by the cluster's effect on the space-time around it.
By measuring the angular separations between the three magnified images of the galaxy a team of astronomers were able to further constrain their measurement of the galaxy's distance from Earth. Much like using your camera to focus on an object and then reading its distance from you on the lens focus ring.
As a result, this is possibly the most reliable distance measurement yet for an object that existed in the Universe's formative years.