to suggest taking the ultimate step:

abandoning that ship and building a new

standard model from the ground up, based on

a revised understanding of gravity. It is hardly

the first such attempt. Now, however, it comes

with a twist – almost literally. By putting a

quantum spin on Einstein’s theories of space

and time, we might finally make sense of the

over-accelerating expansion of everything.

Our understanding of the universe has

continually evolved in response to new

observations. In 1915, when Albert Einstein’s

general theory of relativity described gravity

as a result of mass warping space-time, he

presumed that the universe sculpted by

this large-scale force is static. He even added

A quantum twist

in space-time

The universe is expanding faster than our models

can explain. It might be time for a radical rethink

of how the cosmos works, says Stuart Clark

A

T FIRST, it was a whisper. Now

it has become a shout: there is

something seriously wrong with

our understanding of the cosmos. When

we measure the rate at which the universe

is expanding, we get different results

depending on whether we extrapolate from

the early universe or look at exploding stars

in nearby galaxies. The discrepancy means

that everything is speeding apart more

quickly than we expect.

The problem originally surfaced a few

years ago, and the hope was that it would fade

away with more precise observations. In fact,

the latest measurements have made it

impossible to ignore. “It is starting to get

really serious,” says Edvard Mörtsell, a
cosmologist at Stockholm University in
Sweden. “People must have really screwed
up for this not to be real in some sense.”
Cosmologists have been scrabbling for
answers. They have played around with
the properties of dark energy and dark
matter, those two well-known, yet still
mysterious, components of our standard
model of cosmology. They have imagined
all manner of new exotic ingredients –
all to no avail.
The conclusion could hardly be starker.
Our best model of the cosmos, a seemingly
serenely sailing ship, might be holed beneath
DO the water line. That has led some researchers

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Features Cover story

34 | New Scientist | 28 November 2020