克里斯欽: 時間地圖_ 大歷史130億年前至今
遠期未來：太陽系、銀河系以及宇宙的未來, 頁667
David Christian: Maps Of Time An Introduction To Big History
The Remote Future: The Future Of The Solar System, The Galaxy, And The Universe, p.486
奇怪的是，在最大的時間尺度內模糊性反而消失了，因為天文學家與歷史學家相比，他們研究的對象更大、更簡單，這些對象在漫長的階段變化十分緩慢。天文學家確信，關於行星和恆星，甚至宇宙本身會發生什麼事情他們有很好的想法。
Oddly, the obscurity lifts at the largest scales, for astronomers deal with larger but simpler objects than historians, objects that change very slowly over huge time periods. Astronomers are confident that they have a good idea of what is in store for planets and stars, and even for the universe itself.
生物圈的最後命運取決於地球和太陽的演化。雖然這些都是巨大的體系，但是它們比生物圈或者人類社會更簡單，因此它們未來的演化是可以預測的。我們的太陽處在生命週期的中期，還將有40億年左右的生命。但是地球上的生命將在太陽死去之前全部滅絕。當太陽進入老年時將會更熱，最終令地球表面更熱，生物圈會進化，以減緩這些變化造成的影響，但是最終地球上那些仍然存活的有機生命將喪失選擇的機會。在30億年的時間里，地球將吸收太陽的熱量，就像如今金星那樣；海洋將沸騰，產生的蒸汽將促使全球變熱。地球將變得無法居住。最後它將像今天的月亮那樣一片荒蕪。
The ultimate fate of the biosphere will be determined by the evolution of the earth and its sun. Though these are large systems, they are simpler than the biosphere or human society, so their future evolution is more predictable. Our sun is about halfway through its life cycle, giving it another 4 billion or so years to live. But life on Earth will die out well before the Sun dies. As it ages, the Sun will heat up until eventually the surface of Earth begins to heat up, too. The biosphere may evolve in ways that slow the impact of these changes, but eventually those organisms still living on Earth will run out of options. In 3 billion years' time, Earth will receive as much heat from the Sun as Venus does today; the oceans will boil, and their steam will contribute to massive global warming. Earth will become uninhabit-able. 18 Eventually, it will be as barren as the Moon is today.
太陽燃燒掉全部氫，就將變得不穩定。它將從表面噴射物質，將膨脹到地球如今所在的位置。然而太陽密度和引力的減少也將把地球推向更遠的軌道，也許6000萬千米以外。尼科斯•普蘭佐斯(Nikos Prantzos)描述了從地球上觀察到的景象：“如果有一個觀察者還能夠生活在溫度接近2000°C的地球表面熾熱的爐膛里，他將看見與但丁筆下的地獄相類似的景象。太陽將會佔據整個天空的3/4。”如果有誰看見太陽吞噬地球，他們可能是來自太陽系以外的訪客；那時，木星和土星的衛星木衛二和土衛六會變得可以居住。然後太陽會再度收縮，因為它開始燃燒內部的氨，但是僅持續一億年。當氨燃燒完畢，太陽將會再度不穩定，開始產生氧氣和碳。在這個階段，即使外層行星也不能居住了。然後，太陽中心的燃燒將最終熄滅並收縮成為一顆白矮星——一種密度極高、極熱的星體，由於沒有內部的熱動力，將在一個比它聚變時期長好幾倍的晚年逐漸變冷、變暗。
When the Sun burns up all its hydrogen, it will become unstable. It will eject material from its outer layers, and its inner core, freed from the pressure of these outer layers, will expand until it reaches where the earth is now. However, the Sun's reduced mass and gravitational pull will allow the earth to drift out to a more distant orbit, 6o million kilometers away. Nikos Prantzos describes the resulting view from Earth: "If an observer could survive the fiery furnace on its surface, at temperatures approaching 2000° C, he or she would see a sight worthy of Dante's inferno. The Sun's disk would occupy more than three quarters of the sky. If anyone is watching as the Sun engulfs our earth, they may be visitors from farther out in the solar system; for a time, the moons of Jupiter and Saturn, such as Titan and Europa, may become habitable. Then the Sun will shrink once more, as it starts to burn helium in its core, but only for about 100 million years. When it runs out of helium, it will flare up again and start manufacturing oxygen and carbon. At this stage, even the outer planets will become uninhabitable. Then, the furnaces at the center of the Sun will finally die down and it will shrink into a white dwarf: an extremely dense, brilliantly hot mass of material that, because it has no internal heat engine, will gradually cool and darken during an afterlife lasting many times longer than its fusion phase.
銀河系中數千億顆恆星不會注意到它的死去——不過也許它們應當注意到，因為它將為銀河系的未來提供一個小小的不祥的徵兆。恆星所能生產的物質90%已經耗盡，因此恆星的形成時代已經走向尾聲。從今以後的數百億年中，將不再形成恆星，然後，當現有的恆星開始死亡的時候，光明將會減弱並消失。在一個寒冷、黑暗的宇宙里，能量的梯度將不再增加到足以創造複雜星體的地步；宇宙將變得越來越簡單，第二熱力學定律將越來越有效地展示其昏暗的權威。但是這不會很快發生，也不會逆向發生：較小的恆星就像曾經強大的游擊軍隊的殘餘分子那樣，其壽命比現有的宇宙年齡長好幾倍。然後，再過數萬億年，甚至這些小恆星也會再度變暗，就像它們早年那樣。但是此刻的宇宙就像一個垃圾場，充滿冷卻的、黑暗的物質，如褐矮星、死亡的行星、小行星、中子星以及黑洞等。
The hundreds of billions of stars in the Milky Way will not notice its passing-though perhaps they should, for it will offer a small portent of the galaxy's distant future. About 90 percent of the material from which stars can be manufactured has already been used, so the era of star formation is drawing to a close. In just a few tens of billions of years from now, star formation will cease; then, when the surviving stars start dying, the lights will dim and begin to go out. In a cold, dark universe, energy gradients will no longer be steep enough to create complex entities; the universe will become simpler and simpler, and the second law of thermodynamics will assert its bleak authority more and more effectively. But this will not happen quickly, and not without reverses: the smaller stars, like remnants of a once-powerful guerrilla army, will live for many times the age of the existing universe. Then, a few thousand billion years from now, even they will shut down, and the universe will be dark again, as it was in its early days. But now it will be like a huge cosmic junkyard, full of cold, dark objects such as brown dwarfs, dead planets, asteroids, neutron stars, and black holes.
接下去還會發生什麼呢？我們不能斷定，但是我們知道一些片爪只鱗。未來主要取決於推動宇宙分離的膨脹和將宇宙聚攏的重力平衡。如果有足夠的密度/能量減慢宇宙膨脹以至於停止，那麼也許數萬億年之後，它就會開始收縮。收縮並非如同人們會經想象的那樣是一個逆向的膨脹階段。甚至有一段時期人們假設一次新的大爆炸之後出現“大擠壓”（Big Crunches）這種活力再現的宇宙場景，有些人將其視為現代版本的宇宙循環論，就像瑪雅人心中的宇宙一樣。這些觀念激勵著天文學家試圖詳細地統計宇宙物質/能量的量。一開始，似乎物質的量很少，不足以停止宇宙膨脹，但是逐漸弄清楚了，我們還有無數看不見的宇宙物質/能量。隨著各種間接的方法用於估算暗物質的量，似乎引力和膨脹極微妙地達成了平衡，這表明宇宙最後的命運還不清楚。然而，到20世紀90年代，所謂真空能量的發現為這些爭論提出了一個解決辦法——其中部分原因是因為真空能量自身能夠說明消失的物質/能量，還有部分原因是它似乎確保了宇宙膨脹不會變慢，而是加速，因為真空能量似乎在緩慢地提高宇宙膨脹的速度。
And what will happen next? We do not know for sure, but we know some of the likely scripts. The future depends largely on the balance between ex-pansion, which drives the universe apart, and the force of gravity, which draws it together. If there is enough mass/energy to slow the expansion of the universe to a halt, then, after perhaps a few thousand billion years, the universe must start contracting. The contraction phase will not be a mere reversal of the expansion phase, as some once believed. It was even supposed at one time that "big crunches" might be followed by new big bangs, in a scenario of bouncing universes that some saw as a modern version of cyclical cosmologies, such as those of the Maya. Such ideas encouraged astronomers to attempt a detailed census of the amount of matter/energy in the universe. At first it seemed that there was far too little matter to halt the expansion of the universe, but it gradually became clear that there is a huge amount of matter or energy that we cannot see. And, as various indirect methods were used to estimate the amount of dark matter, it began to appear that gravity and expansion were extraordinarily finely balanced, making the universe's ultimate fate uncertain. In the late 1990s, however, the discovery of so-called vacuum energy offered a resolution to these debates — in part because the vacuum energy could itself account for much of the missing matter/energy, and in part because it seemed to guarantee that the expansion of the universe would not slow but would instead increase, for vacuum energy appears to be gently accelerating the rate at which the universe expands.
目前，大多數天體物理學家相信，宇宙將持續地、永遠地膨脹下去。用他們的行話說，就是它是“開放”而不是“關閉”的。隨著宇宙越來越大，銀河系的空間還會增加，宇宙在變弱的過程中將變得越來越簡單、寒冷和孤獨。美好時光將一去不返。隨著熱物體和冷物體之間的溫差降低，熵就會增加，令複雜實體的形成更加困難，不過繼續膨脹的宇宙將使自己無法徹底達到熱力學動力平衡。隨著宇宙進入老年，光只能來自太空中為數不多的突然爆發，那是由於冷物質團偶然碰撞而形成一些新星。這些孤獨的發光的燈塔將發現自己身處一個巨大的銀河墳場，周圍是數十億顆恆星屍體。引力將推動某些星體進入空間，在那裡每一個星體都將孤獨地忍受煉獄的煎熬，因為它將一直旅行下去，與任何其他物體距離越來越遠，最終消亡在自己的宇宙裡面。那些仍然待在從前銀河系里的恆星屍體將在引力作用下聚集在一起，最後形成巨大的黑洞。黑洞外的其他任何物質都會消失，如果（像某些現代理論所想象的那樣）甚至質子也不是永恆的。也許從宇宙大爆炸之後1030年，宇宙將成為一個黑暗的、寒冷的地方，只有黑洞和飄霧的亞原子粒子充斥其間，它們相互之間的距離以光年計。
Currently, most astrophysicists believe that the universe will keep expanding forever. It is, in their jargon, "open" rather than "closed." As it gets bigger, the spaces between galaxies will increase, and the universe will get simpler, colder, and lonelier in an infinitely slow diminuendo. The good times will be over for good. With the reduction in temperature difference between hot and cold objects, entropy will increase, making the formation of complex entities increasingly difficult, though the continued expansion of the universe will ensure that it never reaches a state of perfect thermodynamic equilibrium. As the universe ages, light will come only from rare flare-ups, as cold lumps of matter collide randomly to form a few new stars. These lonely beacons of light will find themselves in a colossal galactic graveyard, surrounded by billions of stellar corpses. Gravitational forces will push some of the corpses out into empty space, where each will endure a lonely purgatory as it travels farther and farther away from anything else, until finally it perishes in its own private universe. Those star corpses that stay within the former galaxies will be pulled together by gravity until they merge into huge galactic black holes. Any matter left outside them will also begin to decay if (as some modern theories suggest) even protons are not forever. From perhaps 1030 years after the big bang onward, the universe will be a dark, cold place, filled only with black holes and stray subatomic particles that wander light-years apart from each other.
但是斯蒂芬•霍金(Stephen Hawking)在20世紀70年代證明，甚至黑洞也會喪失能量，在經過無數難以想象的時期之後消失。它們因量子蒸發而導致的死亡將持續一段時期，比所有以前經歷時間還要長10多億倍，與這段漫長時期相比，10億年相當於海灘上的一粒沙子。普蘭佐斯(Prantzos,)認為，按照這個比例，黑洞開始統治宇宙之前的1030年，“看上去甚至比今天我們看普朗克時間還要短！”黑洞背後還會留下一些什麼嗎？絕無僅有：保羅•戴維(Paul Davies)想象那是“一盤難以設想的稀湯，由數量逐漸減少的光子、核子以及電子和正電子組成，它們逐漸地、緩慢地遠離對方。就我們所知，再也不會發生更進一步的物理過程了。沒有任何重大事件打擾這個宇宙的淒慘貧瘠，這個宇宙氣數已盡，終將直面永生的宇宙—也許永死是一個比較確切的描述。
But as Stephen Hawking showed in the early 1970s, even black holes lose energy, and over unimaginable periods of time they, too, will disappear. Their deaths by quantum evaporation will last billions of times longer than all the eras that passed before, so long that each billion years will count as no more than a single grain of sand on an earthly beach. On these scales, according to Prantzos, the 1030 years before black holes began to dominate the universe "will look even shorter than the Planck time does for us today!"22 What will the dying black holes leave behind? Very little: Paul Davies imagines "an inconceivably dilute soup of photons, neutrinos, and a dwindling number of electrons and positrons, all slowly moving farther and farther apart. As far as we know, no further basic physical processes would ever happen. No significant event would occur to interrupt the bleak sterility of a universe that has run its course yet still faces eternal life— perhaps eternal death would be a better description.
設想存在一個目睹最後黑洞面臨死亡之煩惱的觀察者，對於他而言，本書所考察的數十億年不過是時間在開始時的一次創造性的耀眼閃光，是巨大的混沌的能量挑戰第二宇宙熱力學定律並且將構成我們世界的稀奇古怪的複雜實體的大雜燴聯合在一起的那一剎那。在這春光乍現之際，在尚未冷卻變黑之前，宇宙的創造性正在大爆發。而至少在一個無名的銀河系里出現了一個聯結成網絡的、智慧的物種，能夠把宇宙當作一個整體進行思考並且重構它的過去。
To an imaginary observer watching the death agony of the last black holes, the few billion years considered in this book will seem like a dazzling flash of creativity at the beginning of time, a split second in which huge and chaotic energies challenged the second law of thermodynamics and conjured up the menagerie of exotic and complex entities that make up our world. In that fleeting springtime, before it cooled and darkened, the universe was bursting with creativity. And in at least one obscure galaxy, there appeared a networked, intelligent species capable of contemplating the universe as a whole and of reconstructing much of its past.
我們不禁要想，這道創造性的閃光是為人類特意安排的—也許這就是宇宙從虛無中創造出來的終極理由。現代科學絕沒有為這樣一種人類中心論的信仰提供充足理由。相反，看來我們只是宇宙在其漫長生命中最年輕、精力最旺盛、最具生育能力的階段上一個比較稀奇古怪的創造。雖然我們不再將自己視為宇宙的中心，或者其存在的終極原因，但是對於許多人而言，這種想法仍然是非常崇高的。
It is tempting to think that this flash of creativity was laid on for humans—the ultimate justification, perhaps, for the universe's creation from nothing. Modern science offers no good reason for believing in such anthropocentrism. Instead, it seems, we are one of the more exotic creations of a universe in the most youthful, exuberant, and productive phase of a very long life. Though we no longer see ourselves as the center of the universe or the ultimate reason for its existence, this may still be grandeur enough for many of us.