Cosmology | Universe Today

Astronomers looking to pinpoint when the reionozation of the Universe took place have found some of the earliest galaxies about 800 million years after the Big Bang. 22 early galaxies were found using a method that looks for far-away redshifting sources that disappear or "drop-out" at a specific wavelength. The age of one galaxy was confirmed by a characteristic neutral hydrogen signature at 787 million years after the Big Bang. The finding is the first age-confirmation of a so-called dropout galaxy at that distant time and pinpoints when the reionization epoch likely began.
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New measurements of the cosmic microwave background (CMB) – the leftover light from the Big Bang – lend further support the Standard Cosmological Model and the existence of dark matter and dark energy, limiting the possibility of alternative models of the Universe. Researchers from Stanford University and Cardiff University produced a detailed map of the composition and structure of matter as it would have looked shortly after the Big Bang, which shows that the Universe would not look as it does today if it were made up solely of 'normal matter'. Read more…

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Theoretical physics has brought us the notion that our single universe is not necessarily the only game in town. Satellite data from WMAP, along with string theory and its 11- dimensional hyperspace idea has produced the concept of the multiverse, where the Big Bang could have produced many different universes instead of a single uniform universe. The idea has gained popularity recently, so it was only a matter of time until someone asked the question of how many multiverses could possibly exist. The number, according to two physicists, could be "humongous."
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One of the newest telescopes in space, the Planck spacecraft, recently completed its "first light" survey which began on August 13. Astronomers say the initial data, gathered from Planck's vantage point at the L2 point in space, is excellent. Planck is studying the Cosmic Microwave Background, looking for variations in temperature that are about a million times smaller than one degree. This is comparable to measuring from Earth the body heat of a rabbit sitting on the Moon.
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Rats! Another perplexing space mystery solved by science. New analysis of the famous "cold spot" in the cosmic microwave background reveals, and confirms, actually, that the spot is just an artifact of the statistical methods used to find it. That means there is no supervoid lurking in the CMB, and no parallel universe lying just beyond the edge of our own. What fun is that?
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If you are into Twitter (as I am), you might enjoy this: New Scientist challenged their readers to encompass the Big Bang into a Tweet. That means the description of the event that started everything that is needs to be 140 characters or less –and actually it was only 133 characters because to qualify, the Tweet had to include the #sci140 hashtag so the folks at New Scientist could gather them all together. Some went the complete science route by trying to summarize the physics (at least one person fit in the equation for Hubble's Law), others quoted ("In the beginning the universe was created. This has made a lot of people very angry and has been widely regarded as a bad move." — Douglas Adams), others took a religious bend, and still others described the event in how it might sound (boom, bang, kaboom or tweeeet). Here's my favorite:

@newscientist < ∞ #sci140 yanikproulx

A fun exercise in brevity.

Here's the rest of their top 10:

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Einstein's general theory of relativity describes gravity in terms of the geometry of both space and time. Far from a source of gravity, such as a star like our sun, space is "flat" and clocks tick at their normal rate. Closer to a source of gravity, however, clocks slow down and space is curved. But measuring this curvature of space is difficult. However, scientists have now used a continent-wide array of radio telescopes to make an extremely precise measurement of the curvature of space caused by the Sun's gravity. This new technique promises to contribute greatly in studying quantum physics.
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The only way to know what the Universe was like at the moment of the Big Bang requires analysis of gravitational waves created when the Universe began. Scientists working with the Laser Interferometer Gravitational-Wave Observatory (LIGO) say their initial investigations of these gravitiation waves have turned up nothing. But that's a good thing. Not detecting the waves provides constraints about the initial conditions of the universe, and narrows the field of where we actually do need to look in order to find them.
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When it comes to universes, perhaps one is enough after all.

Many theories in physics and cosmology require the existence of alternate, or parallel, universes.  But Dr. Lee Smolin of the Perimeter Institute for Theoretical Physics in Waterloo, Canada, explains the flaws of theories that suggest our universe is just one of many, and which also perpetuate the notion that time does not exist.  Smolin, author of the bestselling science book 'The Trouble with Physics' and a founding member of the Perimeter Institute, explains his views in the June issue of Physics World.

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Cosmologists have found a new and quicker technique that establishes the intrinsic brightness of Type Ia supernovae more accurately than ever before. These exploding stars are the best standard candles for measuring cosmic distances and are the tools that made the discovery of dark energy possible. An international team has found a way to do the job of measuring stellar distances in just a single night as opposed to months of observations by simply measuring the ratio of the flux (visible power, or brightness) between two specific regions in the spectrum of a Type Ia supernova. With this new method, a supernova's distance can be determined to better than 6 percent uncertainty.
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The name "dark energy" is just a placeholder for the force — whatever it is — that is causing the Universe to expand. But astronomers are perhaps getting closer to understanding this force. New observations of several Cepheid variable stars by the Hubble Space Telescope has refined the measurement of the Universe's present expansion rate to a precision where the error is smaller than five percent. The new value for the expansion rate, known as the Hubble constant, or H0 (after Edwin Hubble who first measured the expansion of the universe nearly a century ago), is 74.2 kilometers per second per megaparsec (error margin of ± 3.6). The results agree closely with an earlier measurement gleaned from Hubble of 72 ± 8 km/sec/megaparsec, but are now more than twice as precise.
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A new survey is revealing how the most massive galaxies formed in the early Universe, and the findings support the theory that Cold Dark Matter played a role. A team of scientists from six countries used the NICMOS near infrared camera on the Hubble Space Telescope to carry out the deepest ever survey of its type at near infrared wavelengths. Early results show that the most massive galaxies, which have masses roughly 10 times larger than the Milky Way, were involved in significant levels of galaxy mergers and interactions when the Universe was just 2-3 billion years old.
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On April 7th, commands were sent to NASA's exoplanet-hunting Kepler telescope to eject the 1.3×1.7 metre lens cap so the unprecedented mission could begin its hunt for Earth-like alien worlds orbiting distant stars. However, one UK astronomer won't be using the Kepler data to detect the faint transits of rocky exoplanets in front of their host stars. He'll be using it to monitor the light from a special class of variable star, and through the extreme precision of Kepler's optics he will be joining an international team of collaborators to redefine the size of the Universe…
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During the next decade, cosmologists will attempt to observe the first moments of the Universe, hoping to prove a popular theory. They'll be searching for extremely weak gravity waves to measure primordial light, looking for convincing evidence for the Cosmic Inflation Theory, which proposes that a random, microscopic density fluctuation in the fabric of space and time gave birth to the Universe in a hot big bang approximately 13.7 billion years ago. A new instrument called a polarimeter is being attached to the South Pole Telescope (SPT), which operates at submillimeter wavelengths, between microwaves and the infrared on the electromagnetic spectrum. Einstein's theory of general relativity predicts that Cosmic Inflation should produce the weak gravity waves.
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What did the Universe look like early in its history, only 500 million years after the Big Bang? Currently, we have no way of actually "looking" back that far with our telescopes, but cosmologists from Durham University in the UK have used a computer simulation to predict how the very early Universe would have appeared. The images portray the "Cosmic Dawn," and calculate the formation of the first big galaxies. The simulation also attempts to discern the role that dark matter played in galaxy formation. "We are effectively looking back in time and by doing so we hope to learn how galaxies like our own were made and to understand more about dark matter," said Alvaro Orsi, lead author of the study from Durham University's Institute for Computational Cosmology (ICC). "The presence of dark matter is the key to building galaxies – without dark matter we wouldn't be here today."
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