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Keyword: darkenergy

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  • Bringing balance to the universe: New theory could explain missing 95 percent of the cosmos

    12/05/2018 9:02:07 AM PST · by ETL · 89 replies
    Scientists at the University of Oxford may have solved one of the biggest questions in modern physics, with a new paper unifying dark matter and dark energy into a single phenomenon: a fluid which possesses 'negative mass." If you were to push a negative mass, it would accelerate towards you. This astonishing new theory may also prove right a prediction that Einstein made 100 years ago. Our current, widely recognised model of the Universe, called LambdaCDM, tells us nothing about what dark matter and dark energy are like physically. We only know about them because of the gravitational effects they...
  • Discovery of Hotspots Circling Milky Way Black Hole Has Astronomers Excited

    11/21/2018 7:58:43 AM PST · by BenLurkin · 30 replies
    Space.com ^ | November 21, 2018 08:00am ET | Samantha Mathewson,
    Broderick's work builds on earlier research by two teams that studied the galactic center of the Milky Way in near-infrared. This included the work of Reinhard Genzel, an astronomer from the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, as well as researchers Andrea Ghez and Mark Morris of University of California, Los Angeles. At the time, their work revealed that the center of the Milky Way wasn't steady, but instead would drastically brighten about once a day for about 30 or 40 minutes, Broderick said. Researchers think supermassive black holes exist at the center of most, if not...
  • Large, strangely dim galaxy found lurking on far side of Milky Way

    11/13/2018 10:17:10 AM PST · by ETL · 15 replies
    ScienceMag.com ^ | Nov 13, 201 | Adam Mann
    Circling our galaxy is a stealthy giant. Astronomers have discovered a dwarf galaxy, called Antlia 2, that is one-third the size of the Milky Way itself. As big as the Large Magellanic Cloud, the galaxy’s largest companion, Antlia 2 eluded detection until now because it is 10,000 times fainter. Such a strange beast challenges models of galaxy formation and dark matter, the unseen stuff that helps pull galaxies together. “It’s a very odd object and kind of exciting because we don’t know yet how to interpret all of its properties,” says Andrey Kravtsov of The University of Chicago in Illinois,...
  • What Is the “Dark Energy” That Scientists Seek to Measure and Define?

    11/01/2018 7:37:37 AM PDT · by Salvation · 21 replies
    Archdiocese of Washington ^ | 11-01-17 | Msgr. Charles Pope
    What Is the “Dark Energy” That Scientists Seek to Measure and Define? Msgr. Charles Pope • October 31, 2018 • In 1929, Edwin Hubble discovered that the universe was not static but was in fact expanding outward from some point of singularity. At first his fellow scientists ridiculed his theory, labeling it with the term “the big bang.” Even as late as the 1960s I remember being taught in school that the universe was eternal and fixed. That “settled science” has since given way to the current view that the universe is expanding outward—quite rapidly, in fact.There is more,...
  • Bringing Dark Energy Out into the Light

    10/28/2018 1:28:32 PM PDT · by ETL · 32 replies
    Space.com ^ | Oct 18, 2018 | Paul Sutter, Astrophysicist
    Let's talk about dark energy. We've known for about 20 years that the expansion of our universe is accelerating; every day, our cosmos grows bigger and bigger, doing so faster and faster. It's a subtle effect, and it takes extensive and deep cosmological surveys and studies for scientists to notice it. But multiple independent lines of evidence all point to the same conclusion: accelerating expansion. Astronomers quickly cooked up a cool name for that accelerated expansion: dark energy. But now we’re left with the much harder job of finding a culprit — what's causing it? A universal mistake We use...
  • String Theory May Create Far Fewer Universes Than Thought

    07/30/2018 3:26:36 PM PDT · by LibWhacker · 42 replies
    Space.com ^ | 7/30/18 | Clara Moskowitz
    The problem with string theory, according to some physicists, is that it makes too many universes. It predicts not one but some 10500 versions of spacetime, each with their own laws of physics. But with so many universes on the table, how can the theory explain why ours has the features it does? Now some theorists suggest most—if not all—of those universes are actually forbidden, at least if we want them to have stable dark energy, the supposed force accelerating the expansion of the cosmos. To some, eliminating so many possible universes is not a drawback but a major step...
  • Astronomers Just Found 72 Stellar Explosions, but Don’t Know What’s Causing Them

    04/10/2018 7:50:37 PM PDT · by MtnClimber · 39 replies
    Universe Today ^ | 9 Apr, 2018 | Matt Williams
    A supernova is one of the most impressive natural phenomena in the Universe. Unfortunately, such events are often brief and transient, temporarily becoming as bright as an entire galaxy and then fading away. But given what these bright explosions – which occur when a star reaches the end of its life cycle – can teach us about the Universe, scientists are naturally very interested in studying them. Using data from the Dark Energy Survey Supernova (DES-SN) program, a team of astronomers recently detected 72 supernovae, the largest number of events discovered to date. These supernovae were not only very bright,...
  • Astrophysicists Claim They Found a 'Galaxy Without Dark Matter'

    03/28/2018 10:45:44 PM PDT · by BenLurkin · 24 replies
    Live Science ^ | March 28, 2018 01:00pm ET | Rafi Letzter
    Here's a problem: The universe acts like it's a lot more massive than it looks. Take galaxies, those giant, spinning masses of stars. The laws of motion and gravity tell us how fast these objects should turn given their bulk. But observations through telescopes show them spinning way faster than we'd expect, as if they were actually much more massive than the stars we can see indicate. Astrophysicists have come up with two main solutions to this problem. Either there's a lot of mass out there in the universe that we can't detect directly, mass scientists call dark matter, or there's no...
  • Does Dark Energy Exist?

    07/01/2017 7:01:15 PM PDT · by ETL · 55 replies
    Space.com ^ | June 28, 2017 | Paul Sutter, Astrophysicist
    Newsflash: the universe is expanding. We've known that since the pioneering and tireless work of Edwin Hubble about a century ago, and it's kind of a big deal. But before I talk about dark energy and why that's an even bigger deal, I need to clarify what we mean by the word "expanding." The actual observation that you can do in the comfort of your own home (provided you have access to a sufficiently large telescope and a spectrograph) is that galaxies appear to be receding from our own Milky Way. On average, of course: galaxies aren't simple creatures, and...
  • How to catch a ripple in spacetime

    06/19/2016 12:26:13 PM PDT · by MtnClimber · 16 replies
    Ideas.ted.com ^ | 17 Jun, 2016 | Janna Levin
    How do you build a real-world machine to test the most abstract of theories? Janna Levin talks with Rai Weiss, one of the original designers of LIGO, the four-kilometer-long instrument that has now twice detected the distant reverberations of two black holes crashing into one another. Janna Levin is a theoretical physicist — she works with pen and paper to turn the elegant rules of the universe into theory. Rainer Weiss, or Rai, as he’s known, is an experimental physicist — he thinks about how to find and measure something that may or may not exist outside of theory. Weiss...
  • Do We Need to Revise General Relativity?

    05/20/2016 11:56:18 AM PDT · by MtnClimber · 39 replies
    Real Clear Science ^ | Ross Pomeroy
    The idea that our Universe is filled with dark matter has been around for nearly a century. When astronomers noticed that orbital speeds towards the edges of spiral galaxies remain the same or even increase slightly, rather than decrease, they surmised that either there must be some huge unseen mass driving the rotation, or that the laws of gravity given by Einstein's General Relativity need to be changed. They elected the first option. Over that time, cosmologists have accumulated boatloads of evidence in favor of the notion that this invisible, "dark" matter -- which neither interacts with nor emits light...
  • Astronomy Picture of the Day -- LIGO Detects Gravitational Waves from Merging Black Holes

    02/11/2016 4:37:17 PM PST · by SunkenCiv · 30 replies
    NASA ^ | February 11, 2016 | (see photo credit)
    Explanation: Gravitational radiation has been directly detected. The first-ever detection was made by both facilities of the Laser Interferometer Gravitational-Wave Observatory (LIGO) in Washington and Louisiana simultaneously last September. After numerous consistency checks, the resulting 5-sigma discovery was published today. The measured gravitational waves match those expected from two large black holes merging after a death spiral in a distant galaxy, with the resulting new black hole momentarily vibrating in a rapid ringdown. A phenomenon predicted by Einstein, the historic discovery confirms a cornerstone of humanity's understanding of gravity and basic physics. It is also the most direct detection of...
  • Galactic center's gamma rays unlikely to originate from dark matter, evidence shows

    02/05/2016 1:08:03 PM PST · by MtnClimber · 15 replies
    Princeton University ^ | 4 Feb, 2016 | Catherine Zandonella, Office of the Dean for Research
    Bursts of gamma rays from the center of our galaxy are not likely to be signals of dark matter but rather other astrophysical phenomena such as fast-rotating stars called millisecond pulsars, according to two new studies, one from a team based at Princeton University and the Massachusetts Institute of Technology and another based in the Netherlands. Previous studies suggested that gamma rays coming from the dense region of space in the inner Milky Way galaxy could be caused when invisible dark matter particles collide. But using new statistical analysis methods, the two research teams independently found that the gamma ray...
  • Black holes can grow to 50 billion times the mass of the Sun... and then stop

    12/21/2015 1:15:25 PM PST · by Red Badger · 32 replies
    www.ibtimes.co.uk ^ | December 21, 2015 12:30 GMT | By Matt Atherton
    Black holes can only grow if they have a gas disc to feed on NASA Goddard Space Flight Center/Flickr ======================================================================================================== Black holes can only grow to 50 billion times the mass of the Sun, before they lose their only source of 'food' and stop growing. Scientists discovered that black holes have a size limit, as when it gets so big, the gas which feeds the great void loses its energy, and falls into the unknown. A researcher from the University of Leicester analysed the disc of gas which surrounds supermassive black holes at the centre of galaxies. He found that...
  • Dark matter and the dinosaur: New theory challenges notions on origins of human life

    12/12/2015 1:32:59 AM PST · by Squawk 8888 · 22 replies
    National Post ^ | December 12, 2015 | Joseph Brean
    TORONTO — Dark matter inspires many strange theories, but until now few have involved giant lizards and the origins of humanity. If physicist Lisa Randall’s theory is correct, however, there is a clear link between dark matter, the great unknown majority of universal stuff and the extinction of the dinosaurs, which cleared the path for the rise of mammals, including that special species, homo sapiens. Roughly, her idea is that the rotation of a vast disc of dark matter through our solar system dislodged an asteroid from a weak and distant orbit, and sent it hurtling toward Earth, where it...
  • Astronomy Picture of the Day -- A Force from Empty Space: The Casimir Effect

    12/05/2015 10:01:56 PM PST · by SunkenCiv · 11 replies
    NASA ^ | December 06, 2015 | (see photo credit)
    Explanation: This tiny ball provides evidence that the universe will expand forever. Measuring slightly over one tenth of a millimeter, the ball moves toward a smooth plate in response to energy fluctuations in the vacuum of empty space. The attraction is known as the Casimir Effect, named for its discoverer, who, 55 years ago, was trying to understand why fluids like mayonnaise move so slowly. Today, evidence indicates that most of the energy density in the universe is in an unknown form dubbed dark energy. The form and genesis of dark energy is almost completely unknown, but postulated as related...
  • Is Earth Growing a Hairy Dark Matter 'Beard'?

    11/23/2015 4:24:17 PM PST · by BenLurkin · 37 replies
    discovery.com ^ | Nov 23, 2015 03:48 PM ET // by | Ian O'Neill
    Gary Prezeau of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., describes the results of his theoretical model that goes some way to explain how streams of dark matter particles may interact with our planet's gravitational field. "A (dark matter) stream can be much larger than the solar system itself, and there are many different streams crisscrossing our galactic neighborhood," said Prézeau in a JPL press release. "When gravity interacts with the cold dark matter gas during galaxy formation, all particles within a stream continue traveling at the same velocity." As these streams begin to interact with a planet, according to...
  • Leading Harvard physicist has a radical new theory for why humans exist

    11/15/2015 7:47:38 AM PST · by SeekAndFind · 63 replies
    Business Insider ^ | 11/15/2015 | Jessica Orwig
    Where do we come from? There are many right answers to this question, and the one you get depends on who you ask. For example, an astrophysicist might say that the chemical components of our bodies were first forged in the nuclear fires of stars. On the other hand, an evolutionary biologist might look at the similarities between our DNA and that of other primates' and conclude we evolved from apes. Lisa Randall, a theoretical physicist at Harvard University, has a different, and novel answer, which she describes in her latest book, "Dark Matter and the Dinosaurs." Randall has written...
  • The Astronomer Who Wanted to Rearrange the Solar System, Using Nukes

    CalTech astronomer Fritz Zwicky was the first to conceive of dark matter, supernovas and neutron stars. He also had a theory about colonizing the solar system using nuclear bombs. We could terraform other planets, he argued, by pulverizing them and then moving them closer or further from the sun. ...
  • What are white holes?

    10/12/2015 8:35:22 AM PDT · by Red Badger · 40 replies
    phys.org ^ | October 9, 2015 | by Fraser Cain, Universe Today
    White Hole. Credit: universe-review.ca =================================================================================================================== Black holes are created when stars die catastrophically in a supernova. So what in the universe is a white hole? It's imagination day, and we're going to talk about fantasy creatures. Like unicorns, but even rarer. Like leprechauns, but even more fantastical! Today, we're going to talk about white holes. Before we talk about white holes, let's talk about black holes. And before we talk about Black Holes, what's is this thing you have with holes exactly? Black holes are places in the universe where matter and energy are compacted so densely together that their...