Astronomers reveal the Milky Way's galactic address

By Andrew Fazekas | Geekquinox 

For those of us that that get lost in the local shopping mall, stargazers have revealed the ultimate ‘You Are Here’ map ever created.

A new, three-dimensional cosmic street-map reveals where our home galaxy, the Milky Way, resides in relation to more than 100,000 other islands of stars, according to a new study published in the journal Nature this week.

The newly charted galactic neighbourhood contains some hundred million billion suns (100 quadrillion) and stretches some 500 million light years across. To put that into perspective - our Milky Way galaxy stretches only 100,000 light years across and contains some 100 billion suns, including our own. Our solar system sits about the third of the way from our galaxy’s centre – about 28,000 light years distant.

Astronomers have named our newfound home supercluster of galaxies Laniakea, which  is Hawaiian for ‘immeasurable heaven.’

And it appears that the Milky Way lies near the very outskirts – sort of the outer suburbs – of the Laniakea supercluster.

“We have finally established the contours that define the supercluster of galaxies we can call home,” said lead researcher R. Brent Tully, an astronomer at the University of Hawaii at Manoa.

“This is not unlike finding out for the first time that your hometown is actually part of a much larger country that borders other nations.”

For years astronomers have noticed that galaxies appear to form clumps throughout the Universe – forming an intricate filaments with bunches of galaxies or superlusters, strung along like dew drops on a spiders’ web, while interspersed with large voids.

And so our own supercluster is just one of many others scattered across the observable universe, which some experts say spans more than 90 billion light years across.

while there have been maps of our galactic neighbourhood before, there has always been ambiguity surrounding how far it stretched out and which galaxies were actually bound together by gravity. 

The team of astronomers used a new method to chart the extent of the boundaries of the super cluster, mapping out the precise location of 8,000 of its galaxy members by measuring their speeds in relation to the expansion of the universe.

This new data shows that all these thousands of galaxies appear to be migrating towards a great attractor – the core or centre of the supercluster. It’s this weird phenomenon, which is located in the sky occupied by the southern constellation Centaurus, that has complicated efforts to really be able to chart out our local collection of galaxies. 

But now with this newly-minted cosmic map, the team has noticed something even weirder – the possibility that we are part of an even larger, yet unknown, structure. It appears that the Laniakea supercluster is being gravitationally pulled by something much greater.

So while we may know our galactic address by apartment number, street, city and now province, we may still not know the identity or location of our cosmic country.