Hubble captures a nice example of intergalactic microlensing
Cool image time! The picture to the right, cropped to post here, was taken by the Hubble Space Telescope and released this week. I have specifically cropped it to focus on this ringlike feature, as it one of the nicest examples of micro-lensing I have seen. From the caption:
This curious configuration is the result of gravitational lensing, in which the light from a distant object is warped and magnified by the gravity of a massive foreground object, like a galaxy or a cluster of galaxies. Einstein predicted the curving of spacetime by matter in his general theory of relativity, and galaxies seemingly stretched into rings like the one in this image are called Einstein rings.
The lensed galaxy, whose image we see as the ring, lies incredibly far away from Earth: we are seeing it as it was when the Universe was just 2.5 billion years old. The galaxy acting as the gravitational lens itself is likely much closer. A nearly perfect alignment of the two galaxies is necessary to give us this rare kind of glimpse into galactic life in the early days of the Universe.
I am generally a very big skeptic of most astronomical studies that rely on micro-lensing. I don’t deny it happens and has been detected, as in this case. The uncertainties — such as the unknown distance to intervening galaxy that is causing the lensing — always require too many assumptions that make any reliable conclusions difficult.
Nonetheless, this object illustrates the phenomenon perfectly. The light from the distant galaxy is bent around the intervening nearer galaxy so that we that distant galaxy as a ring.
Cool image time! The picture to the right, cropped to post here, was taken by the Hubble Space Telescope and released this week. I have specifically cropped it to focus on this ringlike feature, as it one of the nicest examples of micro-lensing I have seen. From the caption:
This curious configuration is the result of gravitational lensing, in which the light from a distant object is warped and magnified by the gravity of a massive foreground object, like a galaxy or a cluster of galaxies. Einstein predicted the curving of spacetime by matter in his general theory of relativity, and galaxies seemingly stretched into rings like the one in this image are called Einstein rings.
The lensed galaxy, whose image we see as the ring, lies incredibly far away from Earth: we are seeing it as it was when the Universe was just 2.5 billion years old. The galaxy acting as the gravitational lens itself is likely much closer. A nearly perfect alignment of the two galaxies is necessary to give us this rare kind of glimpse into galactic life in the early days of the Universe.
I am generally a very big skeptic of most astronomical studies that rely on micro-lensing. I don’t deny it happens and has been detected, as in this case. The uncertainties — such as the unknown distance to intervening galaxy that is causing the lensing — always require too many assumptions that make any reliable conclusions difficult.
Nonetheless, this object illustrates the phenomenon perfectly. The light from the distant galaxy is bent around the intervening nearer galaxy so that we that distant galaxy as a ring.