In 2004, NASA’ mission WMAP (Wilkinson Microwave Anisotropy Probe) detected a supermassive void (largest structure ever observed in the universe) — a cold area of the sky that stretched on the map of radiation left over from the Big Bang — a strange feature named by astronomers the Cold Spot.
Since then, the Cold Spot has been the focus of many hypotheses. But now, a team of astronomers led by István Szapudi of the Institute for Astronomy at the University of Hawaii, have obtained data that could provide an explanation for the cold spot. Astronomers used data from the Pan-STARRS1 telescope and from NASA’s Wide Field Survey Explorer (WISE) satellite.
According to Szapudi, a “supervoid” 1.8 billion light-years across may be responsible for this Cold Spot. This massive spherical blob was distinctive for its unexpected emptiness. Szapudi described the object as
the largest individual structure ever identified by humanity.
The Cold Spot is located 3 billion light years from Earth, which makes it very close in the cosmic scheme of things. It was found using huge 3D maps created from PS1 and WISE by András Kovács from Eötvös Loránd University in Budapest, Hungary.
This void was found by combining observations taken by PS1 at optical wavelengths with observations taken by WISE at infrared wavelengths to estimate the distance to and position of each galaxy in that part of the sky
This is the greatest supervoid ever discovered.
said András Kovács.
In combination of size and emptiness, our supervoid is still a very rare event. We can only expect a few supervoids this big in the observable universe.
Kovács added that the supervoid is not a vacuum, but rather it contains about 20% less matter than other regions of the universe — about 10,000 less galaxies.
Supervoids are not entirely empty, they’re under-dense.
Next steps Research
The team notes that the existence of the supervoid and its unexpected effect on the CMB do not fully explain the Cold Spot. It only account for about half of the entire Cold Spot, so it could point to the existence of some “exotic physics”.
It is very unlikely that the supervoid and the Cold Spot at the same location are a coincidence
The void itself I’m not so unhappy about. It’s like the Everest of voids – there has to be one that’s bigger than the rest
Prof Carlos Frenk, a cosmologist at the University of Durham said.
But it doesn’t explain the whole Cold Spot, which we’re still in the dark about.
The team plans to continue the investigation on the Cold Spot and supervoid using extra data from PS1 and from the Dark Energy Survey, as well as, another large void located near the constellation Draco.