IF YOU’VE ever felt that time is dragging, you might not be far wrong.

Scientists say time is gradually slowing down and will eventually grind to a halt, freezing everything in an instant.

However, the change is so subtle that it is undetectable to human senses and will become noticeable only over billions of years – when the Earth is long gone.

The idea has been set out by Professor José Senovilla, Marc Mars and Raül Vera of the University of the Basque Country, Bilbao, and University of Salamanca, Spain.

Researchers have long been puzzled by the fact the universe appears to be expanding, when the laws of physics suggest it should be slowing down.

More than a decade ago, astronomers noticed that distant supernovae – exploding stars on the fringes of the universe – seemed to be moving faster than those nearer the centre.

This indicated they were accelerating as they shot through space. Astronomers were able to measure this by using the so-called “red shift” technique.

The system is the same as that of an ambulance siren whose pitch gets higher as it comes towards the listener but lower as it moves away.

Similarly, a star moving away appears redder in colour than one moving towards us.

At the time, scientists suggested the theory of “dark energy” – something we can’t see or even yet detect – to explain what was powering the expansion of the cosmos.

Since then, theoreticians around the world have been trying to find out what dark energy is, or get rid of it.

However, the team’s proposal, which has been published in the journal Physical Review D, suggests that dark energy does not even exist.

Instead, the appearance of acceleration is caused by time itself gradually slowing down, like a clock that needs winding after it has slowed down.

If Senovilla is correct, then things will seem to get faster and faster until time finally disappears.

“Then everything will be frozen, like a snapshot of one instant, forever,” he said.