In this NASA/ESU photo, images of distant galaxies appear as distorted arcs as their light is bent by the strong gravitational fields of the Abell 2218 galaxy cluster. (NASA/ESU photo)

Gravitational lensing will come into focus at Nanaimo Astronomy Society meeting

Guest speaker will discuss how gravitational lenses help astronomers peer into universe’s past

When objects are too distant for even the most powerful telescopes to resolve, astronomers now turn to lenses created by nature to help them see deeper into the most distant regions of the universe.

Karun Thanjavur, a senior astronomy lab instructor with the University of Victoria, will share his knowledge about gravitational lenses at Nanaimo Astronomy Society’s first meeting of 2018 when he presents Peering Through Nature’s Telescope: Gravitational Lensing as a Window Into the Distant Universe.

Thanjavur’s interests as an observational cosmologist includes discovering and using gravitational lenses to study the universe. In 2009, as part of his doctoral thesis, he developed an automated technique to find these natural lenses in images made of the cosmos.

Albert Einstein predicted the possibility of gravitational lensing through his general theory of relativity. The first such lenses were discovered in 1979 and hundreds have been catalogued since.

Simply put, light waves bend as they pass through gravitational fields created by massive objects, such as galaxies.

“If you have a gravitational lens, which is just due to a single galaxy for instance, then the focal length or the magnifying power is fairly limited,” Thanjavur said. “But if you have 100 galaxies put together in what is called a galaxy cluster, then that would magnify, or the boost that you would get in magnification would be much higher… The higher the magnification boost, the fainter the objects that can be magnified and made visible.”

Gravitational fields affect not just visible light, but wave frequencies across the electromagnetic spectrum.

“In fact, the first gravitational lens … was done in the radio wavelengths…” Thanjavur said. “Electromagnetic radiation, being of the same nature – despite whether it’s an X-ray, visible light or radio waves – they all get affected by the same phenomenon.”

When bent light rays converge or become focused near the Earth, the effect is like a camera lens focusing the image on its film or sensor.

“You have different types of lenses and the focus is determined by the curvature – how much [light] is bent – so you can carry that same analogy to a gravitational lens,” Thanjavur said.

Gravitational lensing also allows astronomers to see farther back in time to the early days of formation of galaxies in the universe.

“Even with something like Hubble [space telescope] we haven’t been able to detect those early galaxies, so we had no way of knowing when those first galaxies evolved in the universe,” Thanjavur said. “But with this boost due to gravitational lenses we have been able to travel farther back in time. The biggest surprise was how efficient the universe was at making these galaxies, so we have discovered galaxies within the first billion years of the lifetime of the universe. Like, at a few hundred million years, already the first galaxies were in place. That’s a remarkable thing when you think about how long it takes for things to evolve, given chance occurrences.”

Nanaimo Astronomy Society’s meeting happens Thursday, Jan. 25, 7-9 p.m. at Beban Park social centre.

Admission is free for society members or for non-members attending their first meeting.

For more information, visit www.nanaimoastronomy.com.

Just Posted

Magic in the air at Nanaimo library on Harry Potter Day

VIRL’s Nanaimo North Library branch hosted activities Thursday

Nanaimo Hospital Auxiliary presents NRGH with $550,000 donation

Second time auxiliary presents a cheque topping half a million dollars to hospital

LETTER TO THE EDITOR: Easing overnight park camping bylaw is ‘bonkers’

Who is supposed to enforce the city’s list of restrictions, asks letter writer

Nanaimo’s 1 Port Drive could get a trial run as a temporary bus loop

Prideaux Street bus exchange expected to be relocated for six months this year

Downtown Nanaimo bridge to be closed to vehicle traffic this spring

Vehicles will be prohibited from driving on Bastion Street Bridge for six weeks

VIDEO: Restaurant robots are already in Canada

Robo Sushi in Toronto has waist-high robots that guide patrons to empty seats

Beefs & Bouquets, March 21

To submit a beef or a bouquet to the Nanaimo News Bulletin, e-mail bulletinboard@nanaimobulletin.com

Permit rejected to bring two cheetahs to B.C.

Earl Pfeifer owns two cheetahs, one of which escaped in December 2015

First Nations leader to try for NDP nomination in Nanaimo-Ladysmith

Bob Chamberlin, vice-president of Union of B.C. Indian Chiefs, announces intentions

Folk singer’s globe-trotting taking him to Nanaimo

Lorkin O’Reilly explores the immigrant experience on new album, plays the Vault on Friday, March 22

Scientists disembark in Nanaimo after international expedition probes Pacific salmon

Canadian, American, Russian, Korean and Japanese scientists survey salmon in Gulf of Alaska

LETTER TO THE EDITOR: On climate, think about the children

Our son doesn’t understand that he’s been given a legacy of environmental crises, says letter writer

Short list for new gnome home includes Parksville, Coombs

Five potential locations have been chosen by Howard’s owners who will decide Tuesday

‘Full worm super moon’ to illuminate B.C. skies on first day of spring

Spring has sprung, a moon named in honour of thawing soil marks final super moon until 2020

Most Read