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VIDEO: Finding our place in the universe

West Van-raised, Hawaii-based astronomer Brent Tully leads Space Centre talk tonight

Slow down. You're moving 600 kilometres per second.

That's roughly the speed at which the entire Milky Way is moving through our cosmic neighbourhood, the supercluster Laniakea.

Charting the path of our galaxy and the 100,000 or so other galaxies in Laniakea has been part of the life's work of Brent Tully, a West Vancouver native and award-winning astronomer with Institute for Astronomy in Hawaii.

Tully debuted his name for the supercluster in the September edition of the science journal Nature in which he and his international colleagues first described what is considered one of the largest structures in the observable universe.

"'Lani' means heaven in Hawaiian and 'akea' means very, very large or perhaps limitless," Tully said.

To give an idea of the astronomical proportions, our galaxy alone contains upwards of 400 billion stars and it would take 520 million years for a beam of light to travel from one side of Laniakea to the other.

Tully will be delivering a lecture on his discoveries at the H.R. MacMillan Space Centre in Vancouver on Friday evening.

While it's been known since the late 1970s that galaxies exist in clusters, it was Tully and his colleagues that developed a way to measure the motions of galaxies from the overall expansion of the universe, Tully explained.

Ever since the Big Bang nearly 14 billion years ago, the universe has been expanding outward. Yet within that there are some "peculiar motions" in which galaxies tend to shift position toward large, denser masses made of other galaxies and dark matter - what's known as "the great attractor."

"Where there's a lot of mass, there's a tendency to flow toward that mass. In some places, that's more than a tendency," he said. "It's the downtown area of the Laniakea. It's the bottom of the gravitational well. .. And we're in the suburbs of Laniakea."

To chart a supercluster, Tully and his colleagues need two components: the velocity of a galaxy and accurate distances between them, which they use radio telescopes spectrometers to determine. With those pieces of data, astronomers can calculate which galaxies are moving downtown, and which ones are heading farther out to the suburbs.

The result is a step forward in human knowledge about where our place in the universe is, Tully said.

"We gain knowledge that is useful to us by seeing our relationship to other places. This is taking it onto a huge scale, if you like," he said. "It was kind of a eureka moment for society as a whole when we started seeing these pictures of the Earth from space. Seeing it from afar gives it a reality that brings it home" Tully was recently bestowed with the Viktor Ambartsumain International Prize, the Gruber Foundation Cosmology Prize and the Wempe Award - three of the world's most prestigious recognitions for astronomy, which he shared with colleagues.

Tickets for Tully's 7 p.m. lecture at the Space Centre are available at the door or in advance at 604-738-7827.