按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
they鈥檙e all in the same plane。
they鈥檙e all going around in the same direction。 。 。 。
it鈥檚 perfect； you know。
it鈥檚 gorgeous。
it鈥檚 almost uncanny。
…astronomer geoffrey marcy
describing the solar system
w锛穡銆倄iaoshuo txt锛�
1 HOW TO BUILD A UNIVERSENO MATTER
灏忥紲璇达紲t锛渪t锛炲ぉ锛煛峰爞
how hard you try you will never be able to grasp just how tiny； how spatiallyunassuming； is a proton。 it is just way too small。
a proton is an infinitesimal part of an atom； which is itself of course an insubstantial thing。
protons are so small that a little dib of ink like the dot on this i can hold something in theregion of 500；000；000；000 of them； rather more than the number of seconds contained in halfa million years。 so protons are exceedingly microscopic； to say the very least。
now imagine if you can （and of course you can鈥檛） shrinking one of those protons down to abillionth of its normal size into a space so small that it would make a proton look enormous。
now pack into that tiny； tiny space about an ounce of matter。 excellent。 you are ready to starta universe。
i鈥檓 assuming of course that you wish to build an inflationary universe。 if you鈥檇 preferinstead to build a more old…fashioned； standard big bang universe； you鈥檒l need additionalmaterials。 in fact； you will need to gather up everything there is every last mote and particle ofmatter between here and the edge of creation and squeeze it into a spot so infinitesimallypact that it has no dimensions at all。 it is known as a singularity。
in either case； get ready for a really big bang。 naturally； you will wish to retire to a safeplace to observe the spectacle。 unfortunately； there is nowhere to retire to because outside thesingularity there is no where。 when the universe begins to expand； it won鈥檛 be spreading outto fill a larger emptiness。 the only space that exists is the space it creates as it goes。
it is natural but wrong to visualize the singularity as a kind of pregnant dot hanging in adark； boundless void。 but there is no space； no darkness。 the singularity has no 鈥渁round鈥�
around it。 there is no space for it to occupy； no place for it to be。 we can鈥檛 even ask how longit has been there鈥攚hether it has just lately popped into being； like a good idea； or whether ithas been there forever； quietly awaiting the right moment。 time doesn鈥檛 exist。 there is no pastfor it to emerge from。
and so； from nothing； our universe begins。
in a single blinding pulse； a moment of glory much too swift and expansive for any form ofwords； the singularity assumes heavenly dimensions； space beyond conception。 in the firstlively second （a second that many cosmologists will devote careers to shaving into ever…finerwafers） is produced gravity and the other forces that govern physics。 in less than a minute theuniverse is a million billion miles across and growing fast。 there is a lot of heat now； tenbillion degrees of it； enough to begin the nuclear reactions that create the lighter elements鈥攑rincipally hydrogen and helium； with a dash （about one atom in a hundred million） oflithium。 in three minutes； 98 percent of all the matter there is or will ever be has beenproduced。 we have a universe。 it is a place of the most wondrous and gratifying possibility；and beautiful； too。 and it was all done in about the time it takes to make a sandwich。
when this moment happened is a matter of some debate。 cosmologists have long arguedover whether the moment of creation was 10 billion years ago or twice that or something inbetween。 the consensus seems to be heading for a figure of about 13。7 billion years； but thesethings are notoriously difficult to measure； as we shall see further on。 all that can really besaid is that at some indeterminate point in the very distant past； for reasons unknown； therecame the moment known to science as t = 0。 we were on our way。
there is of course a great deal we don鈥檛 know； and much of what we think we know wehaven鈥檛 known； or thought we鈥檝e known； for long。 even the notion of the big bang is quite arecent one。 the idea had been kicking around since the 1920s； when georges lema？tre； abelgian priest…scholar； first tentatively proposed it； but it didn鈥檛 really bee an activenotion in cosmology until the mid…1960s when two young radio astronomers made anextraordinary and inadvertent discovery。
their names were arno penzias and robert wilson。 in 1965； they were trying to make useof a large munications antenna owned by bell laboratories at holmdel； new jersey； butthey were troubled by a persistent background noise鈥攁 steady； steamy hiss that made anyexperimental work impossible。 the noise was unrelenting and unfocused。 it came from everypoint in the sky； day and night； through every season。 for a year the young astronomers dideverything they could think of to track down and eliminate the noise。 they tested everyelectrical system。 they rebuilt instruments； checked circuits； wiggled wires； dusted plugs。
they climbed into the dish and placed duct tape over every seam and rivet。 they climbedback into the dish with brooms and scrubbing brushes and carefully swept it clean of whatthey referred to in a later paper as 鈥渨hite dielectric material；鈥潯r what is known moremonly as bird shit。 nothing they tried worked。
unknown to them； just thirty miles away at princeton university； a team of scientists led byrobert dicke was working on how to find the very thing they were trying so diligently to getrid of。 the princeton researchers were pursuing an idea that had been suggested in the 1940sby the russian…born astrophysicist george gamow that if you looked deep enough into spaceyou should find some cosmic background radiation left over from the big bang。 gamowcalculated that by the time it crossed the vastness of the cosmos； the radiation would reachearth in the form of microwaves。 in a more recent paper he had even suggested an instrumentthat might do the job： the bell antenna at holmdel。 unfortunately； neither penzias andwilson； nor any of the princeton team； had read gamow鈥檚 paper。
the noise that penzias and wilson were hearing was； of course； the noise that gamow hadpostulated。 they had found the edge of the universe； or at least the visible part of it； 90 billiontrillion miles away。 they were 鈥渟eeing鈥潯he first photons鈥攖he most ancient light in theuniverse鈥攖hough time and distance had converted them to microwaves； just as gamow hadpredicted。 in his book the inflationary universe ； alan guth provides an analogy that helps toput this finding in perspective。 if you think of peering into the depths of the universe as likelooking down from the hundredth floor of the empire state building （with the hundredth floorrepresenting now and street level representing the moment of the big bang）； at the time ofwilson and penzias鈥檚 discovery the most distant galaxies anyone had ever detected were onabout the sixtieth floor； and the most distant things鈥攓uasars鈥攚ere on about the twentieth。
penzias and wilson鈥檚 finding pushed our acquaintance with the visible universe to within halfan inch of the sidewalk。
still unaware of what caused the noise； wilson and penzias phoned dicke at princeton anddescribed their problem to him in the hope that he might suggest a solution。 dicke realized at once what the two young men had found。 鈥渨ell； boys； we鈥檝e just been scooped；鈥潯e told hiscolleagues as he hung up the phone。
soon afterward the astrophysical journal published two articles： one by penzias andwilson describing their experience with the hiss； the other by dicke鈥檚 team explaining itsnature。 although penzias and wilson had not been looking for cosmic background radiation；didn鈥檛 know what it was when they had found it； and hadn鈥檛 described or interpreted itscharacter in any paper； they received the 1978 nobel prize in physics。 the princetonresearchers got only sympathy。 according to dennis overbye in lonely hearts of the cosmos； neither penzias nor wilson altogether understood the significance of what they had founduntil they read about it in the new york times 。
incidentally； disturbance from cosmic background radiation is something we have allexperienced。 tune your television to any channel it doesn鈥檛 receive； and about 1 percent of thedancing static you see is accounted for by this ancient remnant of the big bang。 the next timeyou plain that there is nothing on； remember that you can always watch the birth of theuniverse。
although everyone calls it the big bang； many books caution us not to think of it as anexplosion in the conventional sense。 it was； rather； a vast； sudden expansion on a whoppingscale。 so what caused it？
one notion is that perhaps the singularity was the relic of an earlier； collapsed universe鈥攖hat we鈥檙e just one of an eternal cycle of expanding and collapsing universes； like the bladderon an oxygen machine。 others attribute the big bang to what they call 鈥渁 false vacuum鈥潯r 鈥渁scalar field鈥潯r 鈥渧acuum energy鈥濃�攕ome quality or thing； at any rate； that introduced ameasure of instability into the nothingness that was。 it seems impossible that you could getsomething from nothing； but the fact that once there was nothing and now there