Gravitational Lensing Archives

November 11, 2023November 11, 2023 by Matt Williams

An Epic Collaboration Between Hubble and JWST

This panchromatic view of galaxy cluster MACS0416 was created by combining infrared observations from the NASA/ESA/CSA James Webb Space Telescope with visible-light data from the NASA/ESA Hubble Space Telescope. Credit: NASA/ESA/CSA/STScI

In 2012, as part of the MAssive Cluster Survey (MACS), the Hubble Space Telescope (HST) discovered a pair of colliding galaxy clusters (MACS0416) that will eventually combine to form an even bigger cluster. Located about 4.3 billion light-years from Earth, the MACS0416 cluster contains multiple gravitational lenses that allow astronomers to look back in time and view galaxies as they appeared when the Universe was young. In a new collaboration that symbolizes the passing of the torch, the venerable Hubble and the James Webb Space Telescope (JWST) teamed up to conduct an extremely detailed study of MACS0416.

November 4, 2023November 13, 2023 by Matt Williams

Civilizations Could Use Gravitational Lenses to Transmit Power From Star to Star

A new study shows how Solar Gravitational Lenses (SGLs) could be used to beam power from one system to another.. Credit: NASA/ESA

In 1916, famed theoretical physicist Albert Einstein put the finishing touches on his Theory of General Relativity, a geometric theory for how gravity alters the curvature of spacetime. The revolutionary theory remains foundational to our models of how the Universe formed and evolved. One of the many things GR predicted was what is known as gravitational lenses, where objects with massive gravitational fields will distort and magnify light coming from more distant objects. Astronomers have used lenses to conduct deep-field observations and see farther into space.

In recent years, scientists like Claudio Maccone and Slava Turyshev have explored how using our Sun as a Solar Gravity Lens (SGL) could have tremendous applications for astronomy and the Search for Extratterstiral Intelligence (SETI). Two notable examples include studying exoplanets in extreme detail or creating an interstellar communication network (a “galactic internet”). In a recent paper, Turyshev proposes how advanced civilizations could use stellar gravitational lenses to transmit power from star to star – a possibility that could have significant implications in our search for technosignatures.

October 31, 2023October 31, 2023 by Mark Thompson

Can There Be Double Gravitational Lenses?

The narrow galaxy elegantly curving around its spherical companion in this image is a fantastic example of a truly strange and very rare phenomenon. This image, taken with the NASA/ESA Hubble Space Telescope, depicts GAL-CLUS-022058s, located in the southern hemisphere constellation of Fornax (The Furnace). GAL-CLUS-022058s is the largest and one of the most complete Einstein rings ever discovered in our Universe. The object has been nicknamed by the Principal Investigator and his team who are studying this Einstein ring as the "Molten Ring", which alludes to its appearance and host constellation. First theorised to exist by Einstein in his general theory of relativity, this object’s unusual shape can be explained by a process called gravitational lensing, which causes light shining from far away to be bent and pulled by the gravity of an object between its source and the observer. In this case, the light from the background galaxy has been distorted into the curve we see by the gravity of the galaxy cluster sitting in front of it. The near exact alignment of the background galaxy with the central elliptical galaxy of the cluster, seen in the middle of this image, has warped and magnified the image of the background galaxy around itself into an almost perfect ring. The gravity from other galaxies in the cluster is soon to cause additional distortions. Objects like these are the ideal laboratory in which to research galaxies too faint and distant to otherwise see. — Gravitational Lens GAL-CLUS-022058s taken with NASA/ESA Hubble Space Telescope

If you, like me, have used telescopes to gaze out at the wonders of the Universe, then you too may have been a little captivated by the topic of gravitational lensing. Think about it: how cool is it that the very universe we are trying to explore is actually providing us with telescopes to probe the darkest corners of space and time?

The alignment of large clusters of galaxies is the usual culprit whose gravity bends distant light to give us nature’s own telescopes, but now part-time theoretical physicist Viktor T Toth poses the question, “Can there be multiple gravitational lenses lined up and can they provide a ‘communication bridge’ to allow civilisations to communicate?”

October 25, 2023October 25, 2023 by Brian Koberlein

This Photonic Crystal Bends Light Like a Black Hole

Regular and distorted photonic crystals. Credit: K. Kitamura et.al

One of the first observational tests of general relativity was that the path of light bends in the presence of mass. Not only refracts the way light changes direction as it enters glass or other transparent materials, but bends along a curved bath. This effect is central to a range of physical phenomena, from black holes to gravitational lensing to observations of dark matter. But because the effect is so tiny on human scales, we can’t study it easily in the lab. That could change in the future thanks to a new discovery using distorted photonic crystals.

July 27, 2023July 27, 2023 by Carolyn Collins Petersen

Astronomers Find a Rare “Einstein Cross”

A great example of an Einstein Cross, as seen by Hubble Space Telescope. A "galaxy" with five nuclei is really one galaxy surrounded by a mirage of four images of a distant quasar. The galaxy lies 400 million light years away; the quasar about 8 billion. Credit: NASA/ESA/Hubble

Gravitational lensing is one of astronomy’s great wonders: a natural lens that magnifies the distant universe. Sometimes a lensing system takes the shape of a so-called “Einstein Cross”. Those are rare and amazingly useful ways to study objects far away in space and time.

June 18, 2023June 18, 2023 by Matt Williams

Astronomers See the Same Supernova Four Times Thanks to a Gravitational Lens

A gravitational lens caused by a galaxy in the foreground leading to an "Einstein Cross." Credit: NASA/ESA/STScI

Measuring cosmic distances is challenging, and astronomers rely on multiple methods and tools to do it – collectively referred to as the Cosmic Distance Ladder. One particularly crucial tool is Type Ia supernovae, which occur in binary systems where one star (a white dwarf) consumes matter from a companion (often a red giant) until it reaches the Chandrasekhar Limit and collapses under its own mass. As these stars blow off their outer layers in a massive explosion, they temporarily outshine everything in the background.

In a recent study, an international team of researchers led by Ariel Goobar of the Oskar Klein Centre at Stockholm University discovered an unusual Type Ia supernova, SN Zwicky (SN 2022qmx). In an unusual twist, the team observed an “Einstein Cross,” an unusual phenomenon predicted by Einstein’s Theory of General Relativity where the presence of a gravitational lens in the foreground amplifies light from a distant object. This was a major accomplishment for the team since it involved observing two very rare astronomical events that happened to coincide.

May 3, 2023May 5, 2023 by Matt Williams

Gravitational Lensing is Helping to Nail Down Dark Matter

Using the gravitational lensing technique, a team was able to examine how light from distant quasar was affected by intervening small clumps of dark matter. Credit: NASA/ESA/D. Player (STScI)

According to the most widely-accepted cosmological model, the majority of the mass in our Universe (roughly 85%) consists of “Dark Matter.” This elusive, invisible mass is theorized to interact with “normal” (or “visible”) matter through gravity alone and not electromagnetic fields, neither absorbing nor emitting light (hence the name “dark”). The search for this matter is ongoing, with candidate particles including Weakly-Interacting Massive Particles (WIMPs) or ultralight bosons (axions), which are at opposite extremes of the mass scale and behave very differently (in theory).

This matter’s existence is essential for our predominant theories of gravity (General Relativity) and particle physics (The Standard Model) to make sense. Otherwise, we may need to radically rethink our theories on how gravity behaves on the largest of scales (aka. Modified Gravity). However, according to new research led by the University of Hong Kong (HKU), the study of “Einstein Rings” could bring us a step closer to understanding Dark Matter. According to their paper, the way Dark Matter alters the curvature of spacetime leaves signatures that suggest it could be made up of axions!

April 3, 2023April 3, 2023 by Matt Williams

Astronomers Think They've Found One of the Biggest Black Holes Ever Seen

Artist's impression of an ultramassive black hole (UBH). Credit: ESA/Hubble/DSS/Nick Risinger/N. Bartmann

In 1931, Indian-American physicist Subrahmanyan Chandrasekhar proposed a resolution to Einstein’s Theory of General Relativity that postulated the existence of black holes. By 1972, astronomers obtained the first conclusive evidence that these objects existed in our Universe. Observations of quasars and the center of the Milky Way also revealed that most massive galaxies have supermassive black holes (SMBHs) at their cores. Since then, the study of black holes has revealed that these objects vary in size and mass, ranging from micro black holes (MBHs) and intermediate black holes (IMBHs) to SMBHs.

Using astronomical simulations and a technique known as Gravitational Lensing, an international team of astrophysicists detected what could be the largest black hole ever observed. This ultramassive black hole (UMBH) has a mass roughly 30 billion times that of our Sun and is located near the center of the Abell 1201 galaxy cluster, roughly 2.7 billion light-years from Earth. This is the first time a black hole has been found using Gravitational Lensing, and it could enable studies that look farther into space to find black holes and deepen our understanding of their size and scale.

March 24, 2023March 24, 2023 by Evan Gough

A Rogue Earth and Neptune Might Have Been Found in Older Data

An artist's illustration of a rogue planet, dark and mysterious. Image Credit: NASA

Scientists have found what appear to be rogue planets hidden in old survey data. Their results are starting to define the poorly-understood rogue planet population. In the near future, the Nancy Grace Roman Space Telescope will conduct a search for more free-floating planets, and the team of researchers developed some methods that will aid that search.

January 23, 2023January 23, 2023 by Matt Williams

A Novel Propulsion System Would Hurl Hypervelocity Pellets at a Spacecraft to Speed it up

Graphic depiction of Pellet-Beam Propulsion for Breakthrough Space Exploration. Credits: Artur Davoyan

Today, multiple space agencies are investigating cutting-edge propulsion ideas that will allow for rapid transits to other bodies in the Solar System. These include NASA’s Nuclear-Thermal or Nuclear-Electric Propulsion (NTP/NEP) concepts that could enable transit times to Mars in 100 days (or even 45) and a nuclear-powered Chinese spacecraft that could explore Neptune and its largest moon, Triton. While these and other ideas could allow for interplanetary exploration, getting beyond the Solar System presents some major challenges.

As we explored in a previous article, it would take spacecraft using conventional propulsion anywhere from 19,000 to 81,000 years to reach even the nearest star, Proxima Centauri (4.25 light-years from Earth). To this end, engineers have been researching proposals for uncrewed spacecraft that rely on beams of directed energy (lasers) to accelerate light sails to a fraction of the speed of light. A new idea proposed by researchers from UCLA envisions a twist on the beam-sail idea: a pellet-beam concept that could accelerate a 1-ton spacecraft to the edge of the Solar System in less than 20 years.