Glossary term: Gravitational Lens

Also known as Gravitational lensing

Description: Objects with mass can bend the light that passes nearby. This is most apparent for very massive objects such as galaxy clusters or the black holes at the centers of galaxies. If observers on Earth are looking at a distant object whose light passes by a massive object on its way to Earth, the light from that object will appear distorted. This effect has been used to measure the mass of galaxy clusters and to estimate how much dark matter they contain. A massive object in space that cause this light distortion is called a gravitational lens.

Related Terms:

See this term in other languages

Term and definition status: This term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

Related Media

On the outskirts of a cluster of galaxies is an arc of light. On this arc is a dot, an image of one of the first stars

A gravitational lens magnifies one of the first stars

Caption: This image zooms in on a star formed within the first billion years after the birth of the Universe (at a redshift of 6.2). The Hubble Space Telescope detected this light using a technique called gravitational lensing. A massive galaxy cluster between the observer and the imaged star creates a distorted and warped image of the parent galaxy and reveals its features.
Credit: NASA, ESA, B. Welch (JHU), D. Coe (STScI), A. Pagan (STScI) credit link
License: CC-BY-4.0 Creative Comments Attribution 4.0 International (CC BY 4.0) icons