Vacuum Energy Quantum physics tells us that contrary to appearances, empty space is a bubbling brew of "virtual" subatomic particles that are constantly being created and destroyed. The fleeting particles endow every cubic centimeter of space with a certain energy that, according to general relativity, produces an anti-gravitational force that pushes space apart. Nobody knows what's really causing the accelerated expansion of the universe, however.
Credit: NASA-JSC-ES&IA
真空能
量子物理告訴我們，和表面看起來不同，真空是由亞原子虛粒子組成的泡沫，這些虛粒子不斷地產(chǎn)生又湮滅。這些轉(zhuǎn)瞬即逝的粒子賦予了每立方厘米真空一定量的能量，根據(jù)廣義相對論，這些能量提供了形成空間膨脹的反引力。然而，現(xiàn)在還沒有人知道到底是什么原因造成了宇宙的加速膨脹。
QuasarsThese bright beacons shine to us from the edges of the visible universe and are reminders to scientists of our universe's chaotic infancy.
Quasars release more energy than hundreds of galaxies combined. The general consensus is that they are
monstrous black holes in the hearts of distant galaxies. This image is of quasar 3C 273, photographed in 1979.
Credit: NASA-MSFC
類星體
這些明亮的燈塔從可見宇宙的邊緣照向我們，它們向科學(xué)家暗示我們的宇宙在早期是多么混亂。類星體向外釋放的能量超過數(shù)百個星系能量的總和。一般認為它們是遙遠星系中心的巨大黑洞。這張是類星體3C 273的照片，拍攝于1979年。
NeutrinosNeutrinos are electrically neutral, virtually mass-less elementary particles that can pass through miles of lead unhindered. Some are passing through your body as you read this. These "phantom" particles are produced in the inner fires of burning, healthy stars as well as in the
supernova explosions of dying stars. Detectors are being embedded
underground,
beneath the sea, or into a large chunk of ice as part of
IceCube, a neutrino-detecting project.
Credit: Jeff Miller/NSF/U. of Wisconsin-Madison
中微子
中微子是電中性的、實際上無質(zhì)量的基本粒子（最新的研究表明，中微子有很小的質(zhì)量，譯注），它們可以不受阻礙地穿過數(shù)英里的鉛。在你閱讀這段話時，就有大量中微子穿過你的身體。這些“幽靈”般的粒子來自于恒星內(nèi)部的燃燒（核反應(yīng)可以產(chǎn)生中微子，基本粒子的反應(yīng)也可以產(chǎn)生中微子，譯注），包括壯年恒星以及死亡恒星的超新星爆炸。中微子探測器被深埋在地下以及海洋中，或者置于大塊的冰中，冰塊是被稱為冰立方的中微子探測器的一部分。
AntimatterLike Superman's alter-ego, Bizzaro, the particles making up normal matter also have opposite versions of themselves. An electron has a negative charge, for example, but its
anti-matter equivalent, the positron, is positive. Matter and anti-matter annihilate each other when they collide and their mass is converted into pure energy by Einstein's equation E=mc2. Some futuristic
spacecraft designs incorporate anti-matter engines.
Credit: Penn State U. /NASA-MSFC
反物質(zhì)
就像超人還有與其相反的一面，Bizzaro，組成通常物質(zhì)的基本粒子也有相反的一面。例如，電子帶有負電荷，而它的反粒子，即正電子，帶正電荷。物質(zhì)和反物質(zhì)碰到一塊兒后會碰撞湮滅，同時它們的質(zhì)量會轉(zhuǎn)變?yōu)榧兡芰?，此過程遵守愛因斯坦質(zhì)能方程E=mc[sup]2[/sup].一些未來主義的太空船就是靠反物質(zhì)引擎推動的。
Galactic CannibalismLike life on Earth, galaxies can "eat" each other and evolve over time. The
Milky Way's neighbor,
Andromeda, is currently
dining on one of its satellites. More than a dozen
star clusters are scattered throughout Andromeda, the cosmic remains of past meals. The image above is from a simulation of
Andromeda and our galaxy colliding, an event that will take place in about 3 billion years.
Credit: F. Summers/C. Mihos/L. Hemquist
星系吞食
和地球上的生命一樣，星系也會相互吞食并隨著時間演化。我們銀河系的鄰居，仙女座星系，當前就在吞食著它伴星系中的一個。超過一打的星團分散在仙女星系的周圍，它們是以前的宇宙大餐的遺體。上方的照片是我們的銀河系和仙女星系碰撞的模擬結(jié)果，這次碰撞將在30億年后發(fā)生。
Cosmic Microwave BackgroundAlso known as the
CMB, this radiation is a primordial leftover from the Big Bang that birthed the universe. It was first detected during the 1960s as a radio noise that seemed to emanate from everywhere in space. The CMB is regarded as one of the best pieces of evidence for the theoretical Big Bang. Recent precise measurements by the
WMAP project place the CMB temperature at -455 degrees Fahrenheit (-270 Celsius).
Credit: NASA/WMAP Science Team
宇宙微波背景輻射
即所謂的CMB，這個輻射是創(chuàng)造宇宙的大爆炸的遺跡。1960年代第一次探測到CMB，當時被當做是無線電噪聲，而且似乎是從宇宙所有方向發(fā)射出來的。CMB被當做是大爆炸理論最強有力的證據(jù)之一。當前由WMAP工程做出的精確測量給出CMB輻射溫度是-455華氏度，或者-270攝氏度。
Gravity WavesGravity waves are
distortions in the fabric of space-time predicted by Albert Einstein's theory of general relativity. The waves travel at the speed of light, but they are so weak that scientists expect to detect only those created during colossal cosmic events, such as
black hole mergers like the one shown above.
LIGO and
LISA are two detectors designed to spot the elusive waves.
Credit: Henze/NASA
引力波
引力波是根據(jù)愛因斯坦的廣義相對論預(yù)言的時空結(jié)構(gòu)的變形。引力波以光速傳播，但是引力波的強度是如此微弱，以至于科學(xué)家僅僅期望于探測被強烈宇宙事件制造的引力波，如上面圖片顯示的黑洞合并。LIGO和LISA是兩個用于探測這種難以捉摸的波動的探測器。
Dark MatterScientists think it makes up the bulk of matter in the universe, but it can neither be seen nor detected directly using current technologies. Candidates range from light-weight
neutrinos to invisible
black holes. Some scientists question whether
dark matter is even real, and suggest that the mysteries it was conjured to solve could be explained by a better understanding of gravity.
Credit: Andrey Kravtsov
暗物質(zhì)
科學(xué)家相信暗物質(zhì)組成了宇宙的大部分物質(zhì)，但是利用當前的技術(shù)，既無法看到也無法探測到暗物質(zhì)。暗物質(zhì)的候選者包括極輕的中微子到看不到的黑洞。但有些科學(xué)家質(zhì)疑暗物質(zhì)是否真的存在，建議這種神秘的現(xiàn)象有可能通過對引力的更好理解所解決。
ExoplanetsUntil about the early 1990s, the only known planets in the universe were the familiar ones in our solar system. Astronomers have since identified more than 190 extrasolar planets (as of June 2006). They range from
gargantuan gas worlds whose masses are just shy of being stars to small,
rocky ones orbiting dim, red dwarfs. Searches for a second Earth, however, have so far turned up empty. Astronomers generally believe that better technology is likely to eventually reveal several worlds similar to our own.
Credit: ESO
系外行星
一直到1990年代早期，宇宙中僅知的行星就是在我們太陽系中很熟悉的那幾個。截止2006年6月，天文學(xué)家已經(jīng)確認了超過190個系外行星。包括巨大的類木行星，它們的質(zhì)量只比形成恒星的要求小一些，還有圍繞暗淡紅矮星轉(zhuǎn)動的類地行星。然而，尋找第二個地球的努力，迄今為止仍然毫無所獲。天文學(xué)家普遍相信更好的技術(shù)有望最終發(fā)現(xiàn)一些類似于我們的世界。
Mini-Black HolesIf a radical new
"braneworld" theory of
gravity is correct, then scattered throughout our solar system are thousands of tiny
black holes, each about the size of an atomic nucleus. Unlike their
larger brethren, these mini-black holes are primordial leftovers from the
Big Bang and affect space-time differently because of their close association with a fifth dimension.
Credit: NASA-MSFC
迷你黑洞
如果關(guān)于引力的一個新的激進理論“膜理論”是對的，那么會有數(shù)千個微小的黑洞分散在我們的太陽系，這些小黑洞都只有原子核的大小。和它們的大個同胞不同，這些迷你黑洞是大爆炸產(chǎn)生的，并且對時空的影響不同，因為它們和第五維時空密切相關(guān)。
