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宇宙膨胀源自引力波???<转自 大众科学 > MATHEMATICIANS' ALTERNATE MODEL OF THE UNIVERSE EXPLAINS AWAY THE NEED FOR DARK ENERGY AN ALTERNATIVE THEORY ELIMINATES DARK ENERGY BY PLACING EARTH AT THE CENTER OF EXPANSIONExpanding Universe NASA What dark materials lie behind universal expansion? Maybe none Dark energy is a mysterious force that cosmologists use to fill gaps in our model of why our universe continues its ever-faster expansion. But now two mathematicians have found a way to explain those baffling observations of the universe without the dark energy question mark hanging overhead. Cosmologists first proposed dark energy to explain why astronomers saw supernovae receding into the distance at an accelerating pace. That suggested a massive amount of energy must exist somewhere to counter the gravity that would otherwise slow down such universal expansion. Such dark energy must make up roughly 70 percent of the universe, in addition to 20 percent constituting dark matter. A measly 4 percent belongs to humans, planets and stardust. Mathematicians Blake Temple and Joel Smoller developed a new theory: Earth sits near the center of an expanding wave that began after the Big Bang. That accelerating expansion could have led to the spread of galaxies as astronomers see them today, but would not itself represent a constant accelerating force. The duo from the University of California-Davis and the University of Michigan talked with other mathematicians and astrophysicists to flesh out their calculations. Such an alternative vision of our universe has the attraction of only relying on Einstein's equations of general relativity, Seed Magazine explains. The theory also helps explain another cosmological idea known as the "bubble of underdensity," or the idea that Earth inhabits a low-mass density area of the universe. But cosmologists say that the new expansion theory has problems. First, observations of the Big Bang's afterglow also indicate the existence of dark energy. Simulations also fit rather well with the observed universe expansion when dark energy becomes a factor. And then there's the counterargument based on the Copernican principle that Earth does not have a unique place in the universe. Only time may tell if the elegance of mathematics triumphs over the black sheep of cosmology. For now, the mathematician duo hopes to work out a testable prediction that can truly pit theory against observation.
一周新数字,大众科学,酒精燃料火箭,引力波,月球极点图…… The Week In Numbers: The Alcohol Content Of Rocket Fuel, Ripples From The Big Bang, And More Laser antenna Robert Forward's proposed free-space laser antenna to detect gravity waves from the Crab Nebula. Central satellite of three has laser and beam splitter. Two outer spacecraft have reflectors. Bill Bourne/ Popular Science archives 1979: the year physicist Alan Guth came up with the theory of cosmic inflation, the dramatic expansion that created our universe (this week, scientists found the first direct evidence of Guth's theory) 681 billion pixels: the size of this new interactive map of the moon's north pole Close-Up of a Crater on NASA's Lunar Map NASA/GSFC/Arizona State University 120,000 celestial objects: the astronomical database of this Wi-Fi-connected telescope that finds stars for you Celestron Cosmos 90 GT Wi-Fi Telescope Jonathon Kambouris 66,130 dry martinis: the equivalent alcohol content of the rocket fuel in one V-2 missile A V-2 just launching German Federal Archive 8,592 words: the vocabulary of this trash-talking, Scrabble-playing robot 12,000 square feet: the size of a luxury house from 1964 that may or may not be buried under a New York City park Illustration of an Underground Home Living Room, with an 'Outdoor' View Screened Onto the Windows From the Underground Home pamphlet, hosted online by nywf64.com 140,000 homes: are powered by the world's largest solar power tower field, which began producing electricity this January Ivanpah Overhead Jesse Allen and Robert Simmon, using Landsat data from the U.S. Geological Survey 1 trillion: the number of scents that human noses can distinguish, according to a new study 22.18 billion base pairs: the size of the largest genome sequenced to date Loblolly pine Doug Goldman @ USDA-NRCS PLANTS Database / USDA-NRCS-NPDT 2,300 miles: the range of Taiwan's new stealth catamaran
大众科学 爱因斯坦再次正确预言引力波,宇宙大爆炸理论获得支持 Huge' Physics Finding Supports Big Bang Theory First evidence of gravitational waves sheds light on the creation of the universe. Space-time curvature An artist's conception of the way the mass of Earth warps space-time. Gravitational waves are tiny ripples in this fabric of space-time. Johnstone via Wikimedia Commons Scientists announced today (March 17) that they had found the first direct evidence of the dramatic expansion that created the known universe, known as cosmic inflation, or the "bang" in the Big Bang. This dramatic expansion is thought to have occurred in the first instants of existence, nearly 14 billion years ago, causing the universe to expand beyond the reach of the most powerful telescopes. In 1979, a physicist named Alan Guth came up with the theory of cosmic inflation, and theorized that such an event would create ripples in space-time called gravitational waves. But their existence remained hypothetical. Today, a team of researchers said that they had detected these gravitational waves, using a telescope near the South Pole. "This is huge," Marc Kamionkowski, a researcher at Johns Hopkins University who was not involved in the discovery but who predicted how these gravitational wave imprints could be found, told Scientific American. “It’s not every day that you wake up and find out something completely new about the early universe." He added that the results looked good, although they would need to be verified by others to hold up. The finding seems to support the idea that the observable universe is only one of many, as the New York Times reports: Confirming inflation would mean that the universe we see... is only an infinitesimal patch in a larger cosmos whose extent, architecture and fate are unknowable. Moreover, beyond our own universe there might be an endless number of other universes bubbling into frothy eternity, like a pot of pasta water boiling over. As the Times tells it, Andrei Linde, who first described the most popular variant of inflation, known as chaotic inflation, in 1983, was about to go on vacation in the Caribbean last week when a colleague named Chao-Lin Kuo knocked on his door with a bottle of Champagne to tell him the news. Confused, Dr. Linde called out to his wife, asking if she had ordered Champagne. "And then I told him that in the beginning we thought that this was a delivery but we did not think that we ordered anything, but I simply forgot that actually I did order it, 30 years ago," Dr. Linde wrote in an email. Hear Linde and Kuo tell the story themselves in this video:
1月3日平衡性测试图 将加强人族机械化 暴雪星际2平衡设计师David Kim于今日发布蓝贴公布了最新的平衡性修改测试图,对三个族都进行了一些改动,其中包括神族的主基地大炮台持续时间、蟑螂埋地移动的速度以及人族机械化战术可能性的改动,具体内容如下:Dayvie开发人员原文地址平衡性地1月3日平衡性测试图 将加强人族机械化 图 我们正在准备下一个平衡性测试地图,希望收集大家对以下几点的看法: 光子过载持续时间从60秒减少到40秒 我们认为母舰核心是一个非常全面的单位。他可以很好的支持神族的进攻,比如回城这个技能。但是我们在考虑母舰核心在防守端是否可以稍微削弱一下。我们希望看到人族和虫族在面对神族防守的时候能有更多的进攻和骚扰机会。 埋地蟑螂移动速度提升至2.25 自从上一个平衡性补丁我们提升埋地蟑螂的移动速度后,这项改动似乎并没有起到明显的效果。我们仍然很少在比赛中看到埋地蟑螂移动的战术,所以我们希望再次改动,使得这个战术的出场率增加。也许在这次的加强后,就能在比赛中看到更多虫族玩家使用埋地移动了。 进一步加强人族机械化 我们认为还可以进一步推广机械化的打法。目前我们有以下几个设想:提升坦克对重甲的伤害,使EMP的科技更容易加入机械化中(比如在机械化需要的科技建筑中加入鬼兵的能量升级),增强机械化空军单位等等。但是,这些目前我们仍然无法确定。我们会欣然接受一些更好的建议。 以上这些还尚未定论。我们欢迎大家的反馈,并且会在推出平衡性测试地图前对大家的提议认真考虑。 在我们收集到更多的玩家反馈后,我们会修改以上的改动,或许还会加入其它改动,然后放出平衡性测试地图。
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