Skip to main content

Hubble shows a galaxy’s mirror image due to phenomenon of gravitational lensing

The Hubble Space Telescope is a constant source of beautiful pictures of the wonders of space, and this week’s Hubble image shows a wonderful example of a phenomenon called gravitational lensing, which helps scientists see incredibly distant galaxies. It shows the galaxy SGAS J143845+145407, which appears twice as if in a mirror.

If you’ve heard of gravitational lensing recently, it’s likely because the same phenomenon was also visible in the first deep field image shared from the James Webb Space Telescope. That image showed how extremely distant galaxies were visible due to the bending of spacetime caused by the gravity of galaxy cluster SMACS 0723.

Gravitational lensing has resulted in a mirror image of the galaxy near the center of this image, creating a captivating centerpiece. A third distorted image of the galaxy appears as a bridge between them.
This intriguing observation from the NASA/ESA Hubble Space Telescope shows a gravitationally lensed galaxy with the long-winded identification SGAS J143845+145407. Gravitational lensing has resulted in a mirror image of the galaxy near the center of this image, creating a captivating centerpiece. A third distorted image of the galaxy appears as a bridge between them. ESA/Hubble & NASA, J. Rigby

This Hubble image shows a different version of the same phenomenon. There are three types of gravitational lensing, which occurs when we look at a very massive body like a galaxy cluster that has very strong gravity that warps spacetime and bends light coming from behind it. The first type of gravitational lensing is called microlensing, when an object’s brightness is temporarily increased, and that is useful for detecting exoplanets. The second type seen in the James Webb image is called weak gravitational lensing, when the distant galaxies are seen as stretched because their light is bent by gravity.

But there’s an even more extreme version of this which happens when the foreground object is more massive or the background object is closer, which is called strong gravitational lensing. That’s what is visible in this Hubble image when gravitational lensing has caused the galaxy near the center of the image to appear mirrored, so you see two versions of it.

“Hubble has a special flair for detecting lensed galaxies,” Hubble scientists write. “The telescope’s sensitivity and crystal-clear vision let it see faint and distant gravitational lenses that ground-based telescopes cannot detect because of the blurring effect of Earth’s atmosphere. Hubble was the first telescope to resolve details within lensed images of galaxies and is capable of imaging both their shape and internal structure.”

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
James Webb captures an extremely distant triple-lensed supernova
This observation from the NASA/ESA/CSA James Webb Space Telescope features the massive galaxy cluster RX J2129. Due to Gravitational lensing, this observation contains three different images of the same supernova-hosting galaxy, which you can see in closer detail here. Gravitational lensing occurs when a massive celestial body causes a sufficient curvature of spacetime to bend the path of light travelling past or through it, almost like a vast lens. In this case, the lens is the galaxy cluster RX J2129, located around 3.2 billion light-years from Earth in the constellation Aquarius. Gravitational lensing can cause background objects to appear strangely distorted, as can be seen by the concentric arcs of light in the upper right of this image.

Since the start of science operations of the James Webb Space Telescope in July last year, we've been treated to a flood of images showing space targets from nebulae to deep fields. This month, Webb researchers shared a new image captured by the telescope's NIRCam instrument which shows a both gorgeous field of galaxies and an important astronomical phenomenon called gravitational lensing.

The image features a huge galaxy cluster called RX J2129, located 3.2 billion light-years away, which is acting as a magnifying glass and bending light coming from more distant galaxies behind it. That's what is causing the stretched-out shape of some of the galaxies toward the top right of the image.

Read more
An enormous galaxy cluster warps spacetime in this Hubble image
A massive galaxy cluster in the constellation Cetus dominates the centre of this image from the NASA/ESA Hubble Space Telescope. This image is populated with a serene collection of elliptical and spiral galaxies, but galaxies surrounding the central cluster — which is named SPT-CL J0019-2026 — appear stretched into bright arcs, as if distorted by a gargantuan magnifying glass. This cosmic contortion is called gravitational lensing, and it occurs when a massive object like a galaxy cluster has a sufficiently powerful gravitational field to distort and magnify the light from background objects.

Every week, scientists using the Hubble Space Telescope share an image from this beloved piece of space technology, and this week's image shows a vital astronomical phenomenon in action. While space telescopes can observe very far-off objects if they are bright enough, there is still a lot of the universe that is too far away to observe -- which is why researchers make use of a natural occurrence called gravitational lensing.

Gravitational lensing happens when an object like a galaxy or galaxy cluster has so much mass that it noticeably warps spacetime. Everything with mass bends spacetime somewhat, but usually this effect is so small as to be effectively invisible. But when the object is something with as much mass as a large galaxy or even a collection of galaxies, then this warping can be significant enough for us to observe it.

Read more
Three galaxies are in the process of merging in this Hubble image
A spectacular trio of merging galaxies in the constellation Boötes takes center stage in this image from the NASA/ESA Hubble Space Telescope. These three galaxies are set on a collision course and will eventually merge into a single larger galaxy, distorting one another’s spiral structure through mutual gravitational interaction in the process. An unrelated foreground galaxy appears to float serenely near this scene, and the smudged shapes of much more distant galaxies are visible in the background.

This week's image from the Hubble Space Telescope shows a dramatic collision of three different galaxies. The trio, located in the Boötes constellation, are in the process of merging and will eventually form one single large galaxy.

A spectacular trio of merging galaxies in the constellation Boötes takes center stage in this image from the NASA/ESA Hubble Space Telescope. These three galaxies are set on a collision course and will eventually merge into a single larger galaxy, distorting one another’s spiral structure through mutual gravitational interaction in the process. An unrelated foreground galaxy appears to float serenely near this scene, and the smudged shapes of much more distant galaxies are visible in the background. ESA/Hubble & NASA, M. Sun

Read more