Physicists have found that for the last 7 billion years or so — the anticipated halfway point of the lifetime of the cosmos – galactic expansion has been accelerating. Some unknown force is pushing the galaxies, adding energy to them. A force physicist have named “dark energy”.
“The Big Bang theory says nothing about what banged, why it banged, or what happened before it banged,” observed MIT theoretical physicist and cosmologist Alan Guth, who pioneered the the theory that the universe dramatically expanded in size in a fleeting fraction of a second after the Big Bang.
“The nature of dark matter is one of the biggest mysteries in science and we need to use any related new data to tackle it,” says astronomer Avi Loeb with the Harvard-Smithsonian Center for Astrophysics. Dark matter is “dark” in the sense that it hardly interacts with anything, particularly with light. While dark matter may be too elusive to be found in particle experiments, it can reveal its presence in astronomical observations.
The weekend edition of the “Planet Earth Report” provides a descriptive link to a headline news story by a leading science journalist about an extraordinary discovery, technology, person, or event changing our knowledge of Planet Earth and the future of the human species.
Cosmologists speculate based on hints of twisted light that offer clues to an exotic substance called “quintessence”that could be the unknown force accelerating the expansion of the universe, with implications not only for cosmology, but also for fundamental physics — the standard model of particle physics does not predict its existence. This hypothetical form of dark energy –a relative of the Higgs Field that permeates the cosmos– could be an exotic unknown form of dark energy distinct from any form of or normal matter, radiation, or even dark matter.
The long-held belief that the Milky Way, harboring Earth and our solar system, is relatively static has been dispelled. In a violent, dynamic dance between two galaxies, the dark-matter halo of Large Magellanic Cloud (LMC) –a satellite galaxy one-hundredth as massive as the Milky Way, visible as a faint cloud in the southern hemisphere’s night skies – as observed by its namesake, the 16th century Portuguese explorer Ferdinand Magellan–is pulling and twisting the Milky Way spiral-shaped disc of stars and planets at 115,200 kilometers per hour towards the constellation Pegasus.
“Planet Earth Report” provides descriptive links to headline news by leading science journalists about the extraordinary discoveries, technology, people, and events changing our knowledge of Planet Earth and the future of the human species.
“Early Mars was an extremely active planet from a geological point of view,” said Alberto G. Fairén, a visiting astrobiologist at Cornell University. “The planet had the conditions needed to support the presence of liquid water on the surface – and on Earth, where there’s water, there’s life. “So early Mars was a habitable planet,” he said. “Was it inhabited? That’s a question that the next rover Perseverance will help to answer.”
