Gravitational Lensing Archives

April 17, 2021April 17, 2021 by Brian Koberlein

You Thought Black Hole Event Horizons Looked Strange. Check out Binary Black Hole Event Horizons

The lensing effects can be complex and difficult to calculate. Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell

One of the strangest predictions of general relativity is that gravity can deflect the path of light. The effect was first observed by Arthur Eddington in 1919. While the bending effect of the Sun is small, near a black hole light deflection can be significant. So significant that you need a powerful supercomputer to calculate how light will behave.

April 12, 2021April 12, 2021 by Matt Williams

Gaia Finds 12 Examples of Einstein Crosses; Galaxies Being Gravitationally Lensed so we see Them Repeated 4 Times

Credit and : R. Hurt (IPAC/Caltech)/The GraL Collaboration

In 1915, Einstein put the finishing touches on his Theory of General Relativity (GR), a revolutionary new hypothesis that described gravity as a geometric property of space and time. This theory remains the accepted description of gravitation in modern physics and predicts that massive objects (like galaxies and galaxy clusters) bend the very fabric of spacetime.

As result, massive objects (like galaxies and galaxy clusters) can act as a lens that will deflect and magnify light coming from more distant objects. This effect is known as “gravitational lensing,” and can result in all kinds of visual phenomena – not the least of which is known as an “Einstein Cross.” Using data from the ESA’s Gaia Observatory, a team of researchers announced the discovery of 12 new Einstein Crosses.

April 8, 2021April 8, 2021 by Brian Koberlein

An Intermediate-Mass Black Hole Discovered Through the Gravitational Lensing of a Gamma-ray Burst

An intermediate mass black hole lenses light around it. Credit: Carl Knox, OzGrav

Black holes come in three sizes: small, medium, and large. Small black holes are of stellar mass. They form when a large star collapses at the end of its life. Large black holes lurk in the centers of galaxies and are millions or billions of solar masses. Middle-sized black holes are those between 100 to 100,000 solar masses. They are known as Intermediate Mass Black Holes (IMBHs), and they are the kind we least understand.

February 4, 2021February 10, 2021 by Andy Tomaswick

Dark Energy Survey Finds Hundreds of New Gravitational Lenses

It’s relatively rare for a magical object from fantasy stories to have a analog in real life. A truly functional crystal ball (or palantir) would be useful for everything from military operations to checking up on grandma. While nothing exists to be able to observe the mundanities of everyday life, there is something equivalent for extraordinarily far away galaxies: gravitational lenses. Now a team led by Xiaosheng Huang from Lawrence Berkeley National Laboratory (LBNL) and several universities around the world have published a list of more than 1200 new gravitational lensing candidates.

December 26, 2020February 10, 2021 by Andy Tomaswick

One of the Largest, Most Complete Einstein Rings Ever Seen. Astronomers Call it the “Molten Ring”

The "Molten Ring" is one of the most complete Einstein Rings ever discovered. Credit: NASA

A very rare astronomical phenomenon has been in the headlines a lot recently, and for good reason. It will be hundreds of years until we can see Jupiter and Saturn this close to one another again. However, there are some even more “truly strange and very rare phenomena” that can currently be observed in our night sky. The only problem is that in order to observe this phenomena, you’ll need access to Hubble.

December 13, 2020December 14, 2020 by Matt Williams

If We Used the Sun as a Gravitational Lens Telescope, This is What a Planet at Proxima Centauri Would Look Like

mage of a simulated Earth, at 1024×1024 pixel resolution, at the distance of Proxima Centauri,at 1.3 pc, as projectedby the SGL to an image plane at 650 AU from the Sun. Credit: Toth H. & Turyshev, S.G.

As Einstein originally predicted with his General Theory of Relativity, gravity alters the curvature of spacetime. As a consequence, the passage of light changes as it encounters a gravitational field, which is how General Relativity was confirmed! For decades, astronomers have taken advantage of this to conduct Gravitational Lensing (GL) – where a distant source is focused and amplified by a massive object in the foreground.

In a recent study, two theoretical physicists argue that the Sun could be used in the same way to create a Solar Gravitational Lens (SGL). This powerful telescope, they argue, would provide enough light amplification to allow for Direct Imaging studies of nearby exoplanets. This could allow astronomers to determine if planets like Proxima b are potentially-habitable long before we send missions to study them.

November 27, 2020November 27, 2020 by Paul M. Sutter

A new way to map out dark matter is 10 times more precise than the previous-best method

Simulation of dark matter and gas. Credit: Illustris Collaboration (CC BY-SA 4.0)

Astronomers have to be extra clever to map out the invisible dark matter in the universe. Recently, a team of researchers have improved an existing technique, making it up to ten times better at seeing in the dark.

October 30, 2020October 30, 2020 by Brian Koberlein

Something other than just gravity is contributing to the shape of dark matter halos

The simulated distribution of dark matter in galaxies. Credit: Brinckmann et al.

It now seems clear that dark matter interacts more than just gravitationally. Earlier studies have hinted at this, and a new study supports the idea even further. What’s interesting about this latest work is that it studies dark matter interactions through entropy.

October 8, 2020October 8, 2020 by Brian Koberlein

Gravitational-Wave Lensing is Possible, but it’s Going to be Incredibly Difficult to Detect

This diagram shows how Hubble is able to observe a quasar, a glowing disc of matter around a distant black hole, even though the black hole would ordinarily be too far away to see clearly. Credit: NASA and ESA

Gravity is a strange thing. In our everyday lives, we think of it as a force. It pulls us to the Earth and holds planets in orbits around their stars. But gravity isn’t a force. It is a warping of space and time that bends the trajectory of objects. Throw a ball in deep space, and it moves in a straight line following Newton’s First Law of Motion. Throw the same ball near the Earth’s surface, and it follows a parabolic trajectory caused by Earth’s warping of spacetime around it.

September 14, 2020September 14, 2020 by Brian Koberlein

Small Amounts of Dark Matter are Creating Much Stronger Gravitational Distortions than Anyone Expected to See

A mosaic of telescopic images showing the galaxies of the Virgo Supercluster. It's part of the cosmic web in which a galaxy can exist during part of its evolution. Credit: NASA/Rogelio Bernal Andreo

Dark matter is difficult for astronomers to study, but that doesn’t keep them from trying. And with skill and determination, they continue to find exciting things about the invisible stuff.