A gigantic wall of galaxies at least 1.4 billion light-years wide has been spotted ‘hiding in plain sight’ by astronomers.
The remarkable discovery was announced this week by Daniel Pomarède of Paris-Saclay University and R. Brent Tully and his team of the University of Hawaii.
The colossal cosmic structure scientists have dubbed The South Pole Wall is comparatively close to us, in cosmic terms, at around half a billion light-years away.
The South Pole Wall’s precise size hasn’t yet been measured, but a preliminary estimate puts it at 1.4 billion light years across, and around 600 million light years deep.
The wall lies in a 'hidden zone' of space that's almost impossible to observe (Image: Pomarède et al)
According to the team who detected it using observations of how it affects the motion of 18,000 galaxies "We will not be certain of its full extent, nor whether it is unusual, until we map the universe on a significantly grander scale."
Because the wall is sited beyond the far side of our own Milky Way galaxy astronomers had missed it until now.
Pomarede explained, "One might wonder how such a large and not-so distant structure remained unnoticed.
“This is due to its location in a region of the sky that has not been completely surveyed, and where direct observations are hindered by foreground patches of galactic dust and clouds.
“We have found it thanks to its gravitational influence, imprinted in the velocities of a sample of galaxies”.
He told Vice: “When our visualizations indicated something going on at the celestial South Pole, we were surprised: indeed there were no reports of a large scale structure in this region.”
It’s called the The South Pole Wall because, viewed from an earthly perspective, it its in the direction of the South Pole.
Astronomers have observed numerous ‘walls’ of galaxies.
Scientists hope one day to make a map showing the true shape of the Universe (Image: Pomarède et al)
The largest so far is the is the Hercules-Corona Borealis Great Wall, which at some 10 billion light years wide extends to fully one-tenth of the width of the observable Universe.
But this new object is by far the closest structure of its kind to the Earth.
The Universe isn’t evenly filled with galaxies. Great empty voids exist as well as walls and filaments of galaxies that extend for unimaginable distances.
The largest seen so far, the Boötes void is a virtually empty 'hole' in the Universe that's nearly 330 million light-years in diameter.
Our own galaxy is located on the edge of a comparatively ‘empty’ region of space known by astronomers as the Local Void.
Some day astronomers may be able to visualize how this vast network of walls and bubbles connects together, allowing a leader understanding of the overall shape of the Universe, and how it was created.