The Hubble Space Telescope captured a stunning “mirror image” of a galaxy thanks to the phenomenon of gravitational lensing, a press release from the European Space Agency reveals.
The capture, shown above, appears to be of two galaxies connected to each other. It’s actually just one, called SGAS J143845+145407.
We are seeing magnified galaxy light coming at us from two different sides of a distant galaxy cluster.
Hubble captures a distant ‘mirror galaxy’
Gravitational lensing allows astronomers to look much further into the distant galaxy. This is thanks to a peculiarity of gravity that distorts light passing through the gravitational field of a massive object, such as a galaxy cluster. The object that is distorted by gravity is known as a “lens”.
Crucially, this lensed object is also magnified in the process, meaning that gravitational lensing allows scientists to see incredibly distant objects more clearly. The illustration below shows how light can be warped as it travels the thousands, millions, or billions of light years it takes to reach Earth.
The illustration above shows the phenomenon of gravitational lensing in action. Source: NASA, ESA & L. Calçada
In the new Hubble gravitational lensing image, the galaxy SGAS J143845+145407 is positioned in the exact location behind a small galaxy cluster so that the cluster creates a distorted “mirror image” of the galaxy. Light from SGAS J143845+145407 traveled approximately 6.9 billion years to reach Earth. Meanwhile, the cluster is about 2.8 billion years from Earth.
The Hubble Space Telescope revolutionized gravitational lensing
The first scientific image revealed from the James Webb Space Telescope shows distorted objects that are the result of gravitational distortion and lensing.
SGAS J143845+145407 is a bright infrared galaxy with high star-forming activity, which means it may also be a target for James Webb in the not too distant future. That’s not to say that Hubble’s new observations of the galaxy aren’t extremely valuable. Using Hubble’s gravitational lensing images, scientists were able to reconstruct the distribution of star formation in SGAS J143845+145407 and investigate the spiral galaxy in new detail.
The new images serve as a reminder of Hubble’s great power and the incredible role it has played in astronomy in the more than 30 years since its launch. James Webb may now be at the center of the astronomical community’s attention, but Hubble revolutionized the gravitational lensing method and laid much of the groundwork for James Webb’s technology and observations today.
Both space observatories will continue to capture images of the cosmos, allowing us to peer further into the distant galaxy and past than ever before.