That the universe is expanding is a well known fact. What is less well known is the rate at which this expansion is taking place. Initially, scientists had pegged the value of the Hubble Constant -- a unit that is used to measure the rate of universe's expansion and is named after the astronomer Edwin Hubble -- at roughly 43.7 miles per second per megaparsec (one megaparsec 3.26 million light-years). However, a study published on the preprint website arXiv in April cast doubts over the figure. The study, based on observations of thousands of Cepheid stars and hundreds of Type Ia supernovae, estimated, with an uncertainty of 2.4 percent, that the Hubble Constant is roughly 45.5 miles per second per megaparsec.
April 9, 2013: British cosmologist Stephen Hawking, who has motor neuron disease, gives a talk titled "A Brief History of Mine," to workers at Cedars-Sinai Medical Center in Los Angeles. Stephen Hawking's final paper, which aims to test a theory that proposes parallel universes, appeared today (May 2) in the Journal of High Energy Physics. As Live Science reported at length in March, before the paper was peer-reviewed and officially published, it shares Hawking's final look at one of his earliest theories, the so-called "no-boundary proposal." This idea describes the conditions in the very early universe. Hawking and his co-author, Thomas Hertog, a physicist at the Catholic University of Leuven in Belgium, attempted to resolve thorny questions regarding the multiverse, or the idea that many universes exist side by side.
If you budget just one second for each planet in Hello Games' imponderable No Man's Sky, you'll still spend 5 billion years visiting them all. By that time, our own sun will have become a crimson death star and swallowed us whole. You'll see virtually none of the more than 18 quintillion planets in this space survival game. Scrappy U.K.-based studio Hello Games wanted first to stir imaginations by crafting a digital universe almost as grand as our own. It's rendered on the fly by an absurdly small amount of mathematical code.
A photographer looks at the sky at night to see the annual Geminid meteor shower near Provenzales' rock, in Maira Valley, northern Italy, on Dec. 6, 2016. A new study says the entire universe could be a hologram. Talk about a reality check: The entire universe could be a "vast and complex hologram," scientists reported Monday. Also, even more unsettling, what we think of as reality may be just an illusion. "Imagine that everything you see, feel and hear in three dimensions (and your perception of time) in fact emanates from a flat two-dimensional field," said study co-author Kostas Skenderis of the U.K.'s University of Southampton.
The Higgs boson may be key to understanding the first moments of the universe. If the early universe was too disordered, everything would have collapsed into black holes moments after the big bang. Luckily, this didn't happen, and some new calculations suggest the Higgs boson could be the reason why. Near the start of the beginning of the universe, everything was compressed into a very small space.