平行宇宙里到底有沒有生命？

According to the current dominant theory, if there are other universes out there, they're not likely to have life. But now an international team of researchers has demonstrated that the Multiverse is more hospitable than we thought.

根據(jù)目前的主流學(xué)說，即便存在平行宇宙，里面也不太可能存在生命。但最近，一支國際研究團(tuán)隊(duì)證明平行宇宙比我們想象的更宜居。

The Multiverse hypothesis - wherein our observable Universe is just one of many universes - is a proposed explanation for the not-large-enough amount of dark energy in the empty space in our Universe.We don't really know what dark energy is - it's the name we give to the force that drives the expansion of our Universe, which, contrary to pretty much everything else we observe, accelerates over time instead of slowing down.It constitutes around 70 percent of the Universe - and that's the problem. Because current theories about the origin of the Universe predict that there should be much more dark energy than that.But they also predict that if there were more dark energy than our currently calculable low amount, the Universe would be expanding so fast that matter would dilute before it could form into stars, and planets, and galaxies.Which means we wouldn't exist.

根據(jù)“平行宇宙”假說，除我們的可觀測宇宙外，還存在許多其它宇宙。該假說可以解釋宇宙里暗能量不足的現(xiàn)象。什么是暗能量?誰也不清楚。它指的是推動宇宙加速膨脹的力，占宇宙的70%。問題來了：從有關(guān)宇宙起源的現(xiàn)有學(xué)說推測，暗能量應(yīng)該遠(yuǎn)遠(yuǎn)超過這個(gè)數(shù)量;但如果暗能量遠(yuǎn)多于當(dāng)前計(jì)算量，那么宇宙的膨脹速度會快到物質(zhì)無法形成恒星、行星、星系等——也就是說，我們將不復(fù)存在。

This is where the Multiverse comes in. It proposes that there are many universes outside our own (and there are a number of models for what this might look like), each with a different proportion of dark energy, and ours is one that just happened to have a smaller amount so that life could form.

于是，“平行宇宙”假說誕生了。它提出，在我們的宇宙之外，還存在許多個(gè)平行宇宙，每個(gè)宇宙具有不同的暗能量比例，而我們的宇宙恰好擁有較低比例的暗能量，因此能夠形成生命。這個(gè)解釋非常優(yōu)雅。

It's a very neat explanation - some scientists argue, a little too neat, involving circular reasoning, unbacked by any observational evidence, and untestable.

不過，一些科學(xué)家認(rèn)為，它有點(diǎn)太過優(yōu)雅了，而且涉及“循環(huán)論證”，既缺乏觀測證據(jù)、也無法進(jìn)行檢驗(yàn)。

But we can run tests on our own Universe - and that's exactly what the researchers have done.

不過，我們可以檢驗(yàn)我們的宇宙呀。

Led by physicist Jaime Salcido of Durham University in the UK, the team created enormous simulations of the Universe, tweaking the amount of dark energy using the Evolution and Assembly of GaLaxies and their Environments (EAGLE) project, one of the most realistic simulations of our Universe.And they found that increasing - or decreasing - the amount of dark energy in our Universe, even up to a few hundred times the amount we observed, would only have a modest impact on the formation of stars and planets.

這回，在英國杜倫大學(xué)的物理學(xué)家Jaime Salcido的帶領(lǐng)下，研究團(tuán)隊(duì)創(chuàng)建了龐大的宇宙模擬項(xiàng)目，并調(diào)整暗能量的數(shù)量。研究結(jié)果非常有趣。他們發(fā)現(xiàn)，增加或減少我們宇宙的暗能量數(shù)量(即便增加幾百倍)對恒星和行星的形成只有中等程度的影響。

"For many physicists, the unexplained but seemingly special amount of dark energy in our Universe is a frustrating puzzle," Salcido said."Our simulations show that even if there was much more dark energy or even very little in the Universe then it would only have a minimal effect on star and planet formation, raising the prospect that life could exist throughout the Multiverse."

許多物理學(xué)家認(rèn)為，我們宇宙的暗能量數(shù)量非常特殊，恰好能夠形成生命，這種巧合是個(gè)謎團(tuán)。但這項(xiàng)新研究表明，增加或減少暗能量對恒星和行星的形成沒有太大影響。也就是說，平行宇宙里也可能存在生命。

It also raises another issue: If we don't need the Multiverse to explain our existence, is it still a plausible theory?

不過，現(xiàn)在又有另一個(gè)問題了：如果我們不需要平行宇宙來解釋我們的存在，那么它還算是一個(gè)合理的假說嗎?

According to the researchers, they haven't ruled it out. Instead, they believe that the answer to the dark energy conundrum lays in something we haven't figured out yet.

研究人員表示，他們并不排除這種可能性。他們認(rèn)為，暗能量之謎的答案可能藏在人類尚未發(fā)現(xiàn)的物理學(xué)新定律里。