We’ve glimpsed before the big bang and it’s not what we expected

The big bang wasn’t the start of everything, but it has been impossible to see what came before. Now a new kind of cosmology is lifting the veil on the beginning of time

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We’ve glimpsed before the big bang and it’s not what we expected

The big bang wasn’t the start of everything, but it has been impossible to see what came before. Now a new kind of cosmology is lifting the veil on the beginning of time

By Miriam Frankel

16 February 2026

[New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.]

Rune Fisker

Imagine we had somehow filmed the whole history of the universe and you could play the movie in reverse. It would start off much as things stand today: a vast and elegant web of galaxies and nebulae. But as the tape rewinds, everything begins to shrink until it reaches an evanescent pinprick of energy – a point everyone knows as the big bang.

And that is where the screen goes blank. To ask what came before this is to invite the scorn of scientists and philosophers alike. It is like asking what’s north of the North Pole – a meaningless, impossible question.

Or is it? Over the past few years, a few physicists have honed a way to lift this curtain and peek at what lies beyond. It involves the realisation that, although we can’t solve the equations that describe this epoch exactly, we can sometimes do so roughly – and in many cases, that might still be informative. Eugene Lim at King’s College London, one of the foremost proponents of these ideas, says this field of numerical relativity is starting to reveal insights into previously unanswerable questions.

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As well as cutting through the theoretical confusion about what happened close to the big bang, the work of Lim and others is providing surprising hints of other universes that could have predated and even collided with our own. And that’s just the start. “I think it’s going to become more prevalent as more and more people discover how powerful it is,” says Lim.

The first glimmers of the idea that became the big bang came from the mind of a Belgian priest. In 1927, Georges Lemaître proposed that observations of galaxies receding from us were best explained if the universe is expanding. He later extrapolated from this to suggest that an expanding universe must have begun as a single point – or “primeval atom”, as he put it. The debate raged about whether he was right until 1964, when physicists Arno Penzias and Robert Wilson detected the cosmic microwave background, or CMB, which is often called the afterglow of the big bang. This pattern of light now bathes the whole sky, and its existence proved beyond a doubt that the universe began in a hot, dense state.

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[New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.]

But when it comes to the early universe, physics can take us only so far. We can rewind to a point about 13.7 billion years ago, when the universe was an extremely dense ball of energy – a phase known as the hot big bang. But try to go beyond that, and we are off the map. Some people colloquially think of the big bang as a point of infinite density when time began, but we have no evidence that this so-called singularity happened or, indeed, any equations that can describe it (see “A very short history of the very early universe”, below).

A very short history of the very early universe

The singularity

Extrapolating all the way back, some physicists assume the universe began as a point of infinite density called a singularity. This would have been when time and space “started” – but interpreting what this means is a challenge and there is no proof it happened.

Inflation

This period theoretically lasted a billionth of a trillionth of a trillionth of a second, during which the universe grew by a factor of 1026, from the size of a subatomic particle to about the size of a grapefruit.

The hot big bang

After inflation, we know there was a period of slower (but still fast) expansion. This lasted around 380,000 years, by the end of which the universe had cooled enough for the first subatomic particles to begin to form.

Why can’t we go back any further than the hot big bang? It has to do with the equations of Albert Einstein’s theory of space and time. His equations describe the geometry of space-time, yet they are notoriously hard to solve exactly in all but the simplest of cases. In situations where gravity is extremely powerful – near a black hole, for example, or around the time of the big bang – this becomes impossible.

But since the late 1950s, physicists have toyed with solving these equations, not exactly, but approximately. The original hope was that this method could be used to calculate what gravitational waves – that is, ripples in the fabric of space-time – would look like. It was only in 2005 that scientists managed to do this, unleashing a new era of gravitational wave astronomy that finally came to fruition in 2016, when gravitational waves were finally observed.

Lim dreamed up the idea of using the same method to solve deeper problems in cosmology. The plan was to plug certain starting conditions into the equations and ask a supercomputer to try to solve them roughly – then repeat with slightly different conditions. This would yield information about how space-time would behave under previously unknowable circumstances. At first, Lim thought he might need only basic computer code, but he ended up building an ambitious model to run these calculations. “I like to say that we wanted to build a small, one-man fighter to destroy the Death Star, but ended up building the Death Star instead,” he says.

Testing inflation

Over the past few years, Lim and others have been using this method to probe our foremost hypothesis for what happened before the hot big bang, known as inflation. The theory of inflation was proposed by Alan Guth, Andrei Linde and others in the 1980s to explain why the universe’s matter and energy are so smoothly distributed on the largest scales. This isn’t the most probable state for a universe to start out in, so inflation was proposed as a means of ironing out the creases. In this view, the universe expanded so fast that any tiny lumps were stretched into insignificance.

Yet inflation has several problems. Among them is the bruising critique that we can’t explain what made inflation switch on and then almost instantly switch off again. To grapple with this, physicists invoke the hypothetical inflaton field. A key idea is the “potential” of this field, which you can think of as akin to gravitational potential. If you are at the top of a mountain, the gravitational field has a higher potential than if you are standing on a chair. Similarly, the inflaton field must have had a high potential to switch inflation on, and it must have rapidly fallen, so it switched off.

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To make things more complicated, we know the shape of the inflaton field in space could have been concave or convex, with the curve being steep or shallow. Its exact shape has implications for how inflation occurred – and thus whether it fits with what we know happened later in cosmic history. Studying the CMB has given us clues that the field was very gently concave – but our measurements aren’t precise enough to be fully confident.

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*Original source*