This new discovery challenges our current cosmological model and understanding of the universe. “…this might be taken as the first evidence for the multiverse – and billions of other universes may exist like our own.”
Experts have come across a so-called ‘cold-spot’ anomaly that stretches billions of years across, and they believe it could be caused by a collision with ANOTHER universe. The cold spot was found in the cosmic microwave background—radiation that was left behind by the big bang, the oldest epoch in the history of our universe—when charged electrons and protons first came together to form electrically neutral hydrogen atoms.
The discovery of CMB is hailed as landmark evidence of the Big Bang origin of the universe. Precise measurements of the CMB are critical to cosmology since any proposed model of the universe must explain this radiation.
In the last couple of decades, this ‘ancient’ radiation has been extensively researched by experts across the world. The CMB has a thermal black body spectrum at a temperature of 2.72548±0.00057 K, and as noted by the Royal Astronomical Society, it has some anomalies including the Cold Spot.
This ‘odd’ feature—about 0.00015 degrees colder than its surroundings—was previously claimed to be caused by a huge void, billions of light years across, containing relatively few galaxies.
However, according to a new study led by Ruari Mackenzi and Tom Shanks at Durham University’s Centre for Extragalactic Astronomy and published in the Monthly Notices of the Royal Astronomical Society, the ‘cold-spot’ may be evidence of another universe interacting with ours.
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| The map of the cosmic microwave background (CMB) sky produced by the Planck satellite. Red represents slightly warmer regions, and blue slightly cooler regions. The Cold Spot is shown in the inset. Image: ESA and Durham University |
Scientists explain that the accelerating expansion of the universe causes voids to leave subtle redshifts on light as it passes through via the integrated Sachs-Wolfe effect.
In the case of the CMB this is observed as cold imprints. It was proposed that a very large foreground void could, in part, imprint the CMB Cold Spot which has been a source of tension in models of standard cosmology.
In previous studies, most searches for a supervoid connected to the cold spot estimated distances to galaxies by looking at their colors. More distant galaxies have their light shifted to longer wavelengths, a phenomenon known as a cosmological redshift.
The further away a galaxy is, the higher the observed redshift. Scientists found that by looking at the colors of the galaxies—specifically their redshifts—they could calculate an estimated distances. However, these measurements have yielded results with a high degree of uncertainty.
In their new work, the Durham team presented the results of a comprehensive survey of the redshifts of 7,000 galaxies, harvested 300 at a time using a spectrograph deployed on the Anglo-Australian Telescope.
From this higher fidelity dataset, Mackenzie and Shanks see no evidence of a supervoid capable of explaining the Cold Spot within the standard theory.
Surprisingly, experts discovered that the so-called cold spot region— thought to be underpopulated with galaxies—is in fact split into much smaller voids which are surrounded by various galaxies.
“The voids we have detected cannot explain the Cold Spot under standard cosmology. There is the possibility that some non-standard model could be proposed to link the two in the future but our data place powerful constraints on any attempt to do that,” said Mackenzi.
This means that if the supervoid that explains the cold spot isn’t there, simulations of the standard model of the universe give odds of 1 in 50 that the Cold Spot arose by chance.
“This means we can’t entirely rule out that the Spot is caused by an unlikely fluctuation explained by the standard model. But if that isn’t the answer, then there are more exotic explanations. Perhaps the most exciting of these is that the Cold Spot was caused by a collision between our universe and another bubble universe. If further, more detailed, analysis of CMB data proves this to be the case then the Cold Spot might be taken as the first evidence for the multiverse – and billions of other universes may exist like our own.”
The paper can be found at https://arxiv.org/abs/1704.03814