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The new study—by a group at the University of Canterbury in Christchurch, New Zealand—finds the fit of Type Ia supernovae to a model universe with no dark energy to be very slightly better than the fit to the standard dark energy model.
The discovery was made in the Nuvvuagittuq Greenstone Belt in Northern Quebec in rock known as "banded iron formations." These formations existed billions of years ago, a result of organisms reacting with dissolved iron in the water that covered the planet. Johnathan O'Neil, assistant professor at the University of Ottawa's Department of Earth and Environmental Sciences, holds a sample of rock taken from the area where he and the research team discovered microfossils of the oldest life forms ever found on Earth.However, this mysterious quantity is essentially a place-holder for unknown physics.Current models of the Universe require this dark energy term to explain the observed acceleration in the rate at which the Universe is expanding.The timescape cosmology was found to give a slightly better fit to the largest supernova data catalogue than the ΛCDM cosmology.Unfortunately the statistical evidence is not yet strong enough to rule definitively in favour of one model or the other, but future missions such as the European Space Agency's Euclid satellite will have the power to distinguish between the standard cosmology and other models, and help scientists to decide whether dark energy is real or not.We already have evidence of water at the surface of the Earth by about 4.3 billion years ago." And it's in that water, together with thermal activity below where life began to flourish, first as microorganisms.
Below the surface water, the ocean crust would have been literally bubbling with activity: with hydrothermal vents, the water heated by volcanic activity.
Scientists base this conclusion on measurements of the distances to supernova explosions in distant galaxies, which appear to be farther away than they should be if the Universe's expansion were not accelerating.
However, just how statistically significant this signature of cosmic acceleration is has been hotly debated in the past year.
The difference in the magnitudes of supernovae in the ΛCDM and Timescape cosmologies and the magnitudes the supernovae would appear to have in an empty universe (horizontal dashed line).
Both models show recent apparent acceleration following earlier deceleration.
"Within the last 15, 20 years, we have more and more evidence that that's not the case," he said.