Huntsville, Alabama - Images of galaxies four billion light years away threaten to rip apart modern theories about space and time.
The rays of light that have travelled half way across the universe may force astrophysicists to completely rethink their ideas about the Big Bang which gave birth to the cosmos.
They suggest that time does not flow in incredibly small but finite and measurable bits, or "quanta", as most scientists believe. Instead of time being made up of many individual moments, like grains of sand running through an hour-glass, it appears to move in a seamless, continuous flow.
If this proves to be the case it will cause consternation in the world of astrophysics.
One of the biggest problems concerns the Big Bang. It implies that in the first instant of creation the singularity or "point" that became the universe had infinite temperature and density - something cosmologists have strenuously tried to avoid.
According to current theories, time should be divisible into 20 million trillion, trillion, trillion Planck intervals.
The shortest possible spatial measurement, "the Planck length", is the distance light can travel in one Planck interval - about 0,000000000000000000000000000000001cm (10 to the power of minus 33).
Scientists say time and distances smaller than Planck scales are "fuzzy" because in a fundamental way they cannot be measured.
The theory allows for Planck-scale fluctuations in time and space which translate o minute variations in the speed of light.
However, these variations would only be evident in light that has travelled a great distance. In a similar way, a sprinter running one percent faster than his opponents might win a 10-metre race in a photo finish, while a one percent faster marathon runner will finish hundreds of metres ahead of the rests of the field.
After billions of years, the faster components of a light wave would be far enough ahead of the slower components to make the beam's wave front noticeably distorted, or blurred.
Two astrophysicists from the University of Alabama in Huntsville, tested the theory of quantum time by looking for this blurring in Hubble Space Telescope images of galaxies at least four billion light years away.
Dr Richard Lieu and Dr Lloyd Hillman were taken by surprise when they did not find it. Instead each image showed a sharp, ring-like interference pattern around the galaxy. Not finding the expected blurring suggested that time was not a quantum function and flowed fluidly at intervals infinitely shorter than Planck units of time.
The findings were released in the online "Astrophysical Journal Letters".
Dr Lieu said: "If time doesn't become 'fuzzy' beneath a Planck interval, this discovery will present problems to several astrophysical and cosmological models, including the Big Bang model of the universe."
The Big Bang theory supposes that at the instant of creation, the quantum singularity that became the universe would need to have infinite density and temperature. To avoid that sticky problem, theorists invoked the Planck time.
They said if the instant of creation was also a quantum event, when space and time were both blurry, then you don't need infinite density and temperature at the start of the Big Bang.
"If time moves along like business as usual even at Planck scales, however, you have to reconcile the Big Bang model with an event that isn't just off the scale, it's infinite," Lieu said. - Sapa-DPA