Earendel is the name that’s been given to the farthest star yet found. This shows the star Earendel’s position along a ripple in space-time (dotted line) that magnifies it and makes it possible for the star to be detected over such a great distance—nearly 13 billion light-years. The image also shows a cluster of stars that is mirrored on either side of the line of magnification. The distortion and magnification are created by the mass of a huge galaxy cluster located in between Earth and Earendel. The mass of the galaxy cluster warps the fabric of space, and looking through that space is like looking through a magnifying glass—along the edge of the glass or lens, the appearance of things on the other side are warped as well as magnified.
Hello, Dave! What’s large and blue and can wrap itself around an entire galaxy?
A gravitational lens mirage.
In this Hubble Space Telescope picture the gravity of a luminous red galaxy has gravitationally distorted the light from a much more distant blue galaxy. Such light bending usually results in two discernible images of the distant galaxy, but here the lens alignment is so precise that the background galaxy is distorted into a horseshoe, almost a complete ring. Since such a lensing effect was generally predicted in some detail by Albert Einstein over 70 years ago, rings like this are now known as Einstein Rings. Strong gravitational lenses like this are more than oddities—their multiple properties allow astronomers to determine the mass and dark matter content of the foreground galaxy lenses.