One of science’s most challenging puzzles comes from the fact that the universe is currently expanding faster than it was right after the Big Bang.
But scientists now claim they have found a surprising solution to this decades-old problem.
The Earth, the solar system, and the entire Milky Way are positioned near the centre of a giant, mysterious hole, they say.
Since the cosmos is expanding faster in this local void than elsewhere in the universe, it creates the illusion that expansion is accelerating.
This radical solution could help solve the problem scientists call the ‘Hubble tension’, but it is not without its problems.
Most importantly, our standard view of the universe suggests that matter should be distributed fairly evenly in space without any massive holes.
However, new research shared at the Royal Astronomical Society’s National Astronomy Meeting claims that the ‘sound of the Big Bang’ supports this theory.
According to these new observations, it is 100 million times more likely that we are in a void than not.
The Earth, solar system, and Milky Way may be stranded inside an enormous, mysterious hole (AI-generated impression)
One of science’s big problems is the fact that the rate of expansion in the current universe is about 10 per cent faster than it was in the early universe. Scientists call this problem the ‘Hubble tension’
The Hubble tension arises out of something called the Hubble constant, which records the rate at which the universe is expanding outwards.
We measure this by looking at objects like galaxies and working out how far away they are and how fast they are moving away.
The problem comes when we look back into the early universe by measuring light from extremely distant objects.
Based on our best theories of the universe, these early observations give a totally different value for the Hubble constant than current measurements.
Dr Indranil Banik, an astronomer from the University of Portsmouth, told MailOnline: ‘In particular, the expansion rate today is about 10 per cent faster than expected.
‘The present expansion rate is the most basic parameter of any cosmological model, so this is indeed a serious issue.
‘Imagine if two different measurements of the length of your living room differed by 10 per cent, but both rulers were made by reliable companies. It is like that, but for the whole Universe.’
Dr Banik’s novel solution to this issue is to suggest that it is just the things near Earth that are accelerating faster, rather than the whole universe.
One solution to the Hubble tension is to assume Earth is in a void about one billion light years across and 20 per cent less dense than the universe at large. Matter would be drawn to the edges by gravity, making it seem like the cosmos was expanding faster near Earth
This could be because the Milky Way is near the centre of a low-density void about a billion light-years across and about 20 per cent less dense than the universe as a whole.
If there were a large region with very little matter inside, objects in this hole would be pulled by gravity towards the denser regions at the edges.
As the void empties out, objects will be moving faster away from Earth than they otherwise would be, creating the illusion that the expansion of the universe has sped up.
If this could be proven, it would resolve the Hubble tension without having to add any extra factors like Dark Energy to explain why the universe is accelerating.
The only issue is that the standard model of the universe typically suggests that matter should be fairly evenly spread out on such a large scale.
However, Dr Banik says that the latest observations of the ‘sound of the Bing Bag’ support this idea.
In the first few seconds of the Big Bang, all the matter in the universe was in the form of a super-hot plasma made up of photons and particles called baryons.
As this plasma was squeezed by gravity, it bounced back out, sending acoustic ‘sound’ waves rippling through the cosmos.
Scientists say that this theory is supported by the ‘sound of the Big Bang’, ripples in matter left behind by the initial explosion and still visible in the lingering radiation
These small ripples spread out in the first few seconds of the Big Bang and were frozen in space, creating patterns in the distribution of galaxies. Measurements of these patterns suggest we may be in a void
When the universe cooled, those waves were frozen in place and left a regular pattern of peaks and troughs in the distribution of galaxies known as baryon acoustic oscillations (BAO).
In a large local void where space is expanding quickly, those ripples will appear to be closer than they should be.
Dr Banik says the latest measurements of the BAO line up better with the existence of a void than they do with a smooth universe.
He says: ‘Looking at all the BAO measurements over the last twenty years, the local void model is about one hundred million times more likely than having no void.’
THE BIG BANG THEORY DESCRIBES THE BEGINNING AND EVOLUTION OF THE UNIVERSE
The Big Bang Theory is a cosmological model, a theory used to describe the beginning and the evolution of our universe.
It says that the universe was in a very hot and dense state before it started to expand 13,7 billion years ago.
This theory is based on fundamental observations.
In 1920, Hubble observed that the distance between galaxies was increasing everywhere in the universe.
The Big Bang Theory is a cosmological model, a theory used to describe the beginning and the evolution of our universe, based on observations – including the cosmic background radiation (pictured), which is a like a fossil of radiation emitted during the beginning of the universe, when it was hot and dense
This means that galaxies had to be closer to each other in the past.
In 1964, Wilson and Penzias discovered the cosmic background radiation, which is a like a fossil of radiation emitted during the beginning of the universe, when it was hot and dense.
The cosmic background radiation is observable everywhere in the universe.
The composition of the universe – that is, the the number of atoms of different elements – is consistent with the Big Bang Theory.
So far, this theory is the only one that can explain why we observe an abundance of primordial elements in the universe.
