UVic astrophysicist Julio Navarro stands under the 32-inch telescope at the university. Navarro was part of a team that used data from a much larger telescope in Hawaii to figure out that a a cluster of galaxies is moving in a way that defies understanding.

A discovery, and a mystery, of galactic proportions

Small galaxies behaving somewhat planet-like by orbiting the Andromeda galaxy is both a discovery and a puzzle for UVic scientists

Across our big old universe, objects orbiting other objects is a common astronomical pastime. The moon orbits the Earth, the Earth orbits the sun, the solar system orbits the galactic centre of the Milky Way.

A collaboration of astrophysics and astronomers, including two from the University of Victoria, have discovered something weird – a cluster of small “dwarf” galaxies is rotating in an orderly fashion around Andromeda galaxy, our nearest intergalactic neighbour.

This planet-like behaviour among galaxies has never been detected before and it fails to fit established models of how galaxies evolve. What’s more, the orbit of these dwarf galaxies around Andromeda is so vast, a single rotation is longer than the age of the universe. They haven’t made it around once. A paper discussing this phenomenon was published Friday in the journal Nature.

“It’s a sobering reminder of how fragile our understanding of these things are,” said UVic astrophysics professor Julio Navarro, one of 16 lead scientists involved in the project. “How this is moving cannot be explained. Why a giant structure of galaxies rotate is uncanny, it’s not well understood yet. But it’s cool enough to point out.”

The discovery emerged from the broader Pan Andromeda Archaeological Survey, a three-year survey of a large region of space surrounding Andromeda galaxy, using the 3.6 metre Canada-France-Hawaii Telescope, in Hawaii. UVic professor Alan McConnachie, based at the Herzberg observatory in Saanich, led that project and is another co-author of the paper.

Out of the mass of observations, the team honed in on a number of dwarf galaxies in the neighbourhood of Andromeda, and then followed up with more telescope observations to measure their relative velocities. Rather than randomness, they found uniformity.

Navarro admits he was skeptical when the data started to suggest a group of 15 dwarf galaxies were orbiting in a well-defined plane a million light years in diameter, but only 30,000 light years thick, a similar structure to how planets orbit a star.

“I thought it would be hard to explain. We haven’t seen this often, if ever,” Navarro said. “Most models know how satellite galaxies form. They don’t form. They come over one by one and don’t form a coherent structure.

“I was skeptical at the beginning. It took quite a bit of convincing within the collaboration that we had not missed something. But our confidence grew that this was not a product of chance.”

Due to its sheer size and a spin cycle older than the universe, the apparent forces involved in these orbiting dwarf galaxies are much different than what rotates a galaxy on its axis, or planets around a star, Navarro said.

His personal pet theory is that these galaxies aren’t rotating at all – that they are part of a “filament” of dwarf galaxies being consumed by Andromeda, and are moving with a velocity that mimics rotation from our vantage point  on Earth.

“It might not be an orbit, it might be an object that coming in (to Andromeda) for the first time,” he said. “It is still odd.”

Although this discovery adds a new mystery into the cosmological mix, Navarro, a theorist by trade, isn’t ready to chuck out the theories on galaxy dynamics built from decades of computer modelling and backed by observation.

“Facing an odd finding points to us either not understanding the detailed theory, or that the theory is incorrect. It’s a reminder that there’s a constant need for discovery, and discovery pushes us farther. You learn more from the unexpected than the expected.”

Check out a video of the discovery at http://astro.unistra.fr/Cosmic_Order/Site/Film.html

Navarro will talk about current theories of cosmology for the general public at Café Scientifique on Tuesday, Jan. 8, 6:30 p.m., at Hermann’s Jazz Club. Admission is free. For more click here.

editor@saanichnews.com

 

 

Just Posted

Victoria man has seen no funding after winning a Human Rights Tribunal case against Transport Canada

Chris Hughes was denied a job after describing his depression and won his case 12 years later

22 public toilets in Victoria: 136 people currently peeing

World Toilet Day floats some serious health issues

UVic bugs out during big push for United Way

Teams of UVic students, faculty and staff test stamina by pushing a 1972 VW Beetle around Ring Road.

Victoria Hospitals Foundation Visions gala raises record-breaking cash

Event raised $800,000 for 100 pieces of equipment for Royal Jubilee and Victoria General hospitals

New vertical $10 bill coming into circulation November 19

Viola Desmond is the first Canadian woman to be featured on a bill

Unique technology gives children with special needs more independent play

UVic’s CanAssist refined seven prototypes aided by $1.5M government contribution

Calgary Stampeders back to Grey Cup with 22-14 win over Winnipeg Blue Bombers

Calgary was favoured to win the 2017 and 2016 Grey Cups, but lost to the Toronto Argonauts and Ottawa Redblacks respectively.

‘A giant step forward’: new $10 bill featuring Viola Desmond to enter circulation

A new $10 banknote featuring Viola Desmond’s portrait will go into circulation, just over 72 years after she was ousted from the whites-only section of a movie theatre in New Glasgow, N.S.

Searchers in California wildfire step up efforts; 77 dead

Trump arrived at the oceanside conclave Saturday afternoon after visiting Northern California to survey the wildfire damage in the town of Paradise.

Trump says ‘no reason’ for him to hear Khashoggi death tape

“It’s a suffering tape, it’s a terrible tape. I’ve been fully briefed on it, there’s no reason for me to hear it,” Trump said in the interview.

Canada Post calls for ‘cooling off’ period to allow for mediated talks

The proposal came as Canada Post workers continued their rotating strikes Monday after rejecting the Crown agency’s latest offer.

Metro Vancouver homicide detectives busy after separate weekend deaths

Homicide detectives in Metro Vancouver are investigating separate cases involving two deaths they say appear to be either targeted or suspicious.

High-end B.C. house prices dropping, but no relief at lower levels

But experts say home ownership remains out of reach for many for middle- and lower-income families

NEB approves operating pressure increase to repaired Enbridge pipeline

The pipeline burst outside of Prince George on Oct. 9, now operating at 85 per cent

Most Read