Space and Physics
PUBLISHED
If you ever feel like you spend your whole life trying to get somewhere that keeps moving farther and farther away, then there may be a reason for that. As it turns out, our entire galaxy is being pulled towards an unseen region of space at incredible speed, yet despite our relentless advance, we’re destined to never actually arrive.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.The enigmatic tractor beam in which we are caught is caused by the gravitational force of a huge concentration of mass called the Great Attractor, which lies in the so-called Zone of Avoidance. This is an area of space that we can’t see because it’s obscured by the light and dust of the Milky Way’s galactic plane.
Despite this, we’ve known for about 40 years that our galaxy is moving towards the Great Attractor at roughly 600 kilometers (375 miles) per second. This discovery was made by a group of astronomers known as the Seven Samurai, who observed the speed and direction of motion of 400 elliptical galaxies, ultimately finding that we and many of our cosmic neighbours are being pulled towards something enormous that lies some 150 to 250 million light-years from Earth.
In 2014, researchers figured out what was going on with a bit more precision. Until this point, it was known that the Milky Way and its Local Group of galaxies were all being pulled towards the Virgo cluster, which in turn was being dragged towards a larger group called the Virgo Supercluster. Yet the new observations indicated that this was also drifting towards an even more humongous group known as the Laniakea Supercluster.
At the heart of Laniakea lies the gravitational battery powering the whole operation by sucking everything towards it, and it’s precisely this concentration of mass that we refer to as the Great Attractor. We can’t observe it directly and we don’t know what it contains, but we can quite clearly perceive the effects of the Great Attractor on not just our own galaxy, but about 100,000 others that are all being drawn towards it.
Yet this story doesn’t end as you might expect. Rather than meeting all our galactic neighbours as we finally converge upon the Great Attractor, we are fated to remain apart due to the fact that this cosmic finishing line is continually moving away from us.
The constant expansion of the universe - which may be driven by the force of dark energy - ensures that the distance between ourselves and the Great Attractor is forever increasing, even as we hurtle towards it. For the time being, we’re still close enough to be caught in its gravitational field, but a few billion years from now, the Great Attractor will be so far away from us that the spell will be broken, ensuring we never actually meet.
Talk about a cosmic anticlimax.
