百科知識(shí)視頻之煎蛋小學(xué)堂51 我們會(huì)隨著宇宙的擴(kuò)張而變大嗎？

Physicists tell us that the universe is expanding,but does that mean we expand with it? I mean,if so,wouldn't no one notice because everything would scale up,at the same relative size and it would seem like nothing had changed? Well,the truth is,the universe isn't expanding.

物理學(xué)家告訴我們 宇宙在擴(kuò)張，但這是否意味著我們也在變大呢?我是說 若真如此 不是應(yīng)該沒人注意到 因?yàn)樗械臇|西 都在同比例放大 因而看似一切都沒變過嗎?真相是 宇宙并不在擴(kuò)張。

Space is,Of course,everything else in the universe is "in"space,and ignoring the influence of any other forces,when the space between things expands,those things will appear to be carried farther apart.But there are other forces in the universe,and their strengths aren't directly affected when space expands.

而空間在擴(kuò)張 當(dāng)然 宇宙中的一切都在空間“之內(nèi)”，忽略其他力產(chǎn)生的影響，當(dāng)事物之間的空間擴(kuò)張時(shí)，這些事物看起來像是被拆散到更遠(yuǎn)處。但是宇宙中還有其他的力，當(dāng)空間擴(kuò)張時(shí) 它們的強(qiáng)度并不會(huì)被直接影響。

For example,gravity and electromagnetism are able to hold atoms and solar systems together,because these forces are too strong for the slow expansion of space to overcome,Think of it like this-if you and your cat are standing on a piece of ground.that starts to stretch horizontally between you,the ground will pull you and your cat away from each other.

比如 重力和電磁力可將原子 太陽系等拉到一起 因?yàn)檫@些力要遠(yuǎn)大于克服空間緩慢擴(kuò)張所需的力。這么想想看 如果你和你的貓都站在一塊地面上 地面開始在你們之間水平拉伸，并將把你和你的貓拉離對(duì)方。

But if the leash is strong enough -in particular if it's stronger than the friction force between your feet and the ground,it'll hold you and your cat together as space expands beneath you.In the real universe,it's the strength of the electromagnetic force that determines the effective sizes of particles,atoms,and molecules,so that even if the space they're in expands,the molecules don't.

但如果皮帶夠結(jié)實(shí) 尤其是，如果它強(qiáng)于你的腳和地面間的摩擦力的話，當(dāng)你腳下的空間擴(kuò)張時(shí) 它能把你和你的貓拉在一起。在真實(shí)的宇宙中 是電磁力的大小 決定著微粒 原子和分子的有效直徑 因而即便其所處的空間擴(kuò)張 這些分子不會(huì)擴(kuò)大。

Electromagnetism is basically the leash that holds atoms and molecules together,and gravity is the leash that holds solar systems and galaxies together,Only over super super long distances is gravity's attraction weak enough,and the cumulative expansion of all that space big enough to cause galaxies and galactic clusters to actually grow more distant from one another over time.we know this because the light from distant galaxies gets red-shifted as it's stretched by the expansion of the space it's traveling through.

電磁力基本上就是那將原子和分子拉在一起的皮帶 而引力也是將太陽系 星系等凝聚在一起的皮帶。只有在特別特別遠(yuǎn)的距離下 引力影響才會(huì)足夠小 空間擴(kuò)張的積累影響才會(huì)足夠大 并導(dǎo)致 星系和銀河星團(tuán)隨著時(shí)間過去 相互間距離越來越遠(yuǎn) 我們知道這個(gè)是因?yàn)檫h(yuǎn)處星云發(fā)出的光出現(xiàn)了紅移 光波被所穿過空間的擴(kuò)張拉長了。

Gravity certainly still pulls distant objects towards each other,but space expands faster,Basically,the cat is off the leash.

當(dāng)然 引力仍然會(huì)將遙遠(yuǎn)的物體相互拉近，但是空間擴(kuò)張更快。基本就是說 那只“貓”掙脫了皮帶。