Get $20 off your contacts by clicking the link in the description or by entering the code real life floor at check out The limits of human vision is an interesting thing.

點擊描述中的鏈接或在結賬時輸入代碼real life floor即可獲得20美元的隱形眼鏡優惠人類視覺的極限是一件有趣的事情。

If you're fortunate enough to have 2020 eyesight, it means that you can clearly read a small Rove text from 20 ft away.

如果你有幸擁有2020年的視力，就意味著你可以在20英尺外清晰地閱讀一小段羅夫的文字。

But the best recorded vision in humans is 2010 eyesight, which means that these extremely lucky people can see things clearly at 20 ft away, as if they were only 10 ft away.

但人類有記錄的最佳視力是2010年的視力，這意味著這些極度幸運的人可以在20英尺外清晰地看到東西，就像他們只有10英尺遠一樣。

For the normal person, everybody sees the world a little bit differently than everybody else does.

對於正常人來說，每個人看到的世界都和別人有一點不同。

And I mean that literally not only in terms of clarity or blurriness, but also in terms of just how much can be viewed.

我的意思是，從字面上看，不僅是指清晰度或模糊度，而且是指能看多少。

If we took you right now and placed you in the middle of the ocean on a clear day with nothing to obstruct your view, you'd probably be able to see in every direction for around five kilometers.

如果我們現在帶著你，在一個晴朗的日子裡，把你放在海中央，沒有任何東西阻擋你的視線，你大概能看到五公里左右的各個方向。

But that can change depending on your height.

但這可以根據你的身高而改變。

The limit to your own personal visibility of the world is determined by two things the curvature of the earth's surface, and how high up your eyes are that are doing the viewing.

你個人對世界的能見度的限制是由兩件事決定的，地球表面的曲率，以及你的眼睛在多高的地方進行觀看。

That's because the higher up your eyes are the more of the earth's surface you can see before it curves away from you.

那是因為你的眼睛越高，在地球表面從你身上彎曲開來之前，你能看到的地球表面就越多。

The average American male is 5 ft 9.5 inches tall, which allows a visible range of about three miles in every direction from sea level.

美國男性的平均身高為5英尺9.5英寸，這使得從海平面開始，每個方向的可視範圍約為3英里。

The average American woman is 5 ft four inches tall, though, which puts a slight negative modifier on their viewing range, so it becomes about 2.8 miles.

不過美國女性平均身高為5英尺4英寸，這讓她們的觀看範圍有了輕微的負修飾，所以變成了2.8英里左右。

That's not a huge variation, but radical height differences can cause that at 7 ft one shack has a higher visible range of 3.3 miles and burn.

這不是一個巨大的變化，但激進的高度差異會導致，在7英尺的時候，一個棚屋的可見範圍較高，有3.3英里和燃燒。

Taylor had only 2 ft eight inches, had a visible range limited toe only two miles.

泰勒只有2英尺8英寸，可見的範圍只有2英里。

However, Robert Pershing Wadlow, the tallest human to have ever existed at 8 ft 11 inches tall, had a massive visual range of 3.7 miles, probably the furthest of any human who has ever lived.

然而，羅伯特-佩辛-瓦德洛，有史以來最高的人類，身高8英尺11英寸，擁有3.7英里的巨大視覺範圍，可能是有史以來人類中最遠的。

If all of these people were standing on a flatboat in the middle of the ocean, Robert would be able to see another boat emerging from the horizon 1.7 miles further out than Verne Taylor could possibly see it.

如果這些人都站在海洋中央的一艘扁舟上，羅伯特就能看到另一艘船從地平線上出現，比維恩-泰勒可能看到的還要遠1.7英里。

But of course you can actually see things further away than just a few miles.

不過當然，其實你可以看到更遠的東西，不只是幾里路。

You only need to get your eyes further up into the sky.

你只需要讓你的眼睛再往天上看。

One of the tallest observation decks anywhere in the world is inside the Burj Khalifa in Dubai.

世界上最高的觀景臺之一就在迪拜的哈利法塔內。

At 555 m up from all the way up here, your line of sight extends out to 84 kilometers.

從這裡一直往上爬555米，你的視線可以延伸到84公里。

In addition to whatever you could see based on your personal height, this is so high up that it becomes possible to see the coast of Iran all the way across the Persian Gulf under optimal conditions.

除了根據個人身高可以看到的任何東西，這裡的高度，變得可以在最佳條件下看到伊朗的海岸，一直到波斯灣。

It's also so high up that it causes some other weird situations up on the higher levels.

也正是因為太高了，所以在更高的層次上造成了其他一些奇怪的情況。

It becomes possible to see the sun setting several minutes after it's already set on the surface once again because of the earth's curvature, and your viewing perception from so high up allows you to see further around that curvature.

由於地球的曲率，在太陽已經落下地表幾分鐘後，再一次看到太陽落下就成為可能，你從這麼高的地方觀看感知，可以看到更遠的曲率周圍。

This has led some local Islamic clerics in Dubai to rule that those living above the 80th floor in the building should wait two additional minutes before breaking their Ramadan fast.

這使得迪拜當地的一些伊斯蘭教神職人員規定，住在80層以上的人在破除齋戒前要多等兩分鐘。

And those living above the 150th floor should wait three additional minutes to give the sun Mawr timeto actually set for them.

而住在150層以上的人，應該多等3分鐘，讓太陽真正落下的時間對他們來說。

In fact, being near the Burj Khalifa actually allows you to witness the sunset twice in the same day.

事實上，在哈利法塔附近，其實可以在同一天內見證兩次日落。

I don't know what that means for Ramadan, so let me know in the comments.

我不知道這對齋月意味著什麼，所以在評論中讓我知道。

But essentially you could watch the sunset happened on the surface and then take the elevator up to the observation deck, which is fast enough that you could get all the way up to the top and witnessed the sunset happen all over again.

但基本上你可以在地表上看日落髮生，然後乘電梯上到觀景臺，電梯速度很快，你可以一直上到頂層，目睹日落髮生的一切。

Similarly, to buildings being high upon mountains or hills can also increase how far away you can actually see something on the earth's surface.

同樣，建築物高高在上，也可以增加你在地球表面實際看到的東西的距離。

In theory, standing atop the summit of Mount Everest should give the largest field of view anywhere in the world out up to 340 kilometers in every direction.

理論上講，站在珠穆朗瑪峰的頂峰，應該是世界上任何地方最大的視野，從各個方向看，最遠可達340公里。

If Mount Everest was in the middle of Germany, that would give you the ability to see over roughly the entire country.

如果珠穆朗瑪峰在德國的中部，那你就可以看到整個國家的大概情況。

But Everest is kind of surrounded by other mountains, which spoils the view.

但是珠峰周圍都是其他的山，這就破壞了景色。

The longest line of sight that anybody can achieve on Earth is by standing atop the summit of Don Cova in Kyrgyzstan and gazing a ludicrous 538 kilometers away to the Hindu Tog Mountain Pass in China.

站在吉爾吉斯斯坦的東科瓦峰頂，凝視538公里外的中國興都託格山口，是地球上任何人都能達到的最長視線。

This is only possible to see under the right weather circumstances, but nowhere else on the planet.

這隻有在合適的天氣環境下才有可能看到，但在地球上其他地方是看不到的。

Is it possible to see something else with your naked eyes that's over 500 kilometers away for reference.

是否可以用肉眼看到500多公里外的其他東西作為參考。

That would be like standing in New York City and being able to see Toronto or standing in Los Angeles and being able to see Sacramento, or for a European comparison standing in London and being able to see either Edinburgh or cologne in Germany.

這就好比站在紐約市，能夠看到多倫多，或者站在洛杉磯，能夠看到薩克拉門託，或者在歐洲比較，站在倫敦，能夠看到德國的愛丁堡或者科隆。

But so far we've only been talking about how far away you can see something on earth surface.

但到目前為止，我們只是在討論你能在多遠的地方看到地球表面的東西。

Your eyes can see things that are much, much further away when you turn them upwards towards space.

當你的眼睛向上朝向空間時，你的眼睛可以看到更多更遠的東西。

Most of the stars in the night sky that you can see are located within a few 1000 light years away from you, a light year, meaning the the distance that light travels within one year, the furthest single object that your naked eye can see while on earth is V 76 to cast in the Cassiopeia Constellation at 16,308 light years away.

你能看到的夜空中的大多數星星都位於離你幾千光年之內，一光年，指的是光在一年內的傳播距離，你在地球上時，肉眼能看到的最遠的單個天體是距離你16308光年的仙后座V 76要投。

But much further away than that is the Andromeda Galaxy, a collection of objects which represents the furthest possible limit of your own naked eye sight into the cosmos.

但比這更遠的地方是仙女座星系，它是一個天體的集合，代表了自己肉眼看向宇宙的最遠極限。

Andromeda is faintly visible without the need for a telescope at a massive distance of approximately 2.5 million light years away.

在距離約250萬光年的巨大距離上，不需要望遠鏡就能隱約看到仙女座。

For most of human history, this served as the furthest limit for our vision and perception of the universe until the advancement of telescopes.

在人類歷史的大部分時間裡，這是我們對宇宙的視野和感知的最遠極限，直到望遠鏡的進步。

Now we can see things that our ancestors never could have, like the Galaxy GNC 11 at 32 billion light years away from us.

現在，我們可以看到我們的祖先永遠無法看到的東西，比如距離我們320億光年的銀河系GNC 11。

Somewhat confusingly, you may remember from previous videos that I've made that the universe itself is only about 13.8 billion years old.

有點困惑的是，你可能還記得我之前做的視頻，宇宙本身的年齡只有138億年左右。

The reason that GNC 11 is 32 billion light years away is that it probably doesn't exist anymore.

GNC 11之所以在320億光年之外，是因為它可能已經不存在了。

It's so far away from us that we're witnessing what it looked like 13.4 billion years ago because that's how long it's taken the light to reach us for us to observe it here on Earth.

它離我們如此之遠，以至於我們目睹了它在134億年前的樣子，因為那是光線到達我們這裡的時間，我們才能在地球上觀察到它。

But this galaxy probably isn't at the edge of the universe.

但這個星系可能並不在宇宙的邊緣。

It's just impossible for us right now to see anything that's probably beyond it.

只是我們現在不可能看到任何可能超越它的東西。

The universe is expanding quicker than the speed of light can move to catch up with it, which means that the light of objects more distant than GNC 11 will never reach us here on Earth, which means that will never be able to see what lies beyond.

宇宙的膨脹速度超過了光速的移動速度，無法追上它，這意味著比GNC 11更遙遠的物體的光永遠無法到達我們地球這裡，也就是說，永遠無法看到外面的東西。

This problem will become worse and worse as time goes on, though, as the universe continues to expand eventually, sometime between four and six billion years from now, the only objects in the night sky that will remain visible on Earth, if it still exists by then, will be our own small local cluster of Galaxies.

不過隨著時間的推移，這個問題會越來越嚴重，隨著宇宙的不斷膨脹，最終，在40億年到60億年後的某一天，夜空中唯一還能在地球上看到的天體，如果到時候還存在的話，那就只有我們自己的局部小星系團了。

The universe as we know it today that's filled with trillions of Galaxies, will be totally invisible and unknowable to civilisations of the future, which means that they may mistakenly think that the universe is much smaller than it actually is.

我們今天所知道的充滿萬億星系的宇宙，對於未來的文明來說，將是完全看不見、摸不著的，這意味著他們可能會誤以為宇宙比實際小得多。

But we may think that ourselves.

但我們自己可能會這麼想。

A few billion years ago, it was probably possible to see even more Galaxies than we can currently see today, since the universe hadn't expanded quite a much.

幾十億年前，由於宇宙還沒有擴張不少，所以可能看到的銀河系甚至比我們現在能看到的還要多。

There's no telling what lies beyond the limit of what we can see in the universe and will probably never know.

我們不知道在我們能看到的宇宙極限之外還有什麼，可能永遠也不會知道。

It's a serious and unsolvable problem that will per permanently affect humanity's collective vision.

這是一個嚴重的、無法解決的問題，將永久影響人類的集體視野。

But back on Earth, your own personal vision problems can actually be solved and solved easily.

但回到地球上，自己的個人視力問題其實是可以解決的，而且很容易解決。

My normal eyesight is naturally 2080 which means that without any correction, I see things that are only 20 ft away, as if they were actually 80 ft away for a normal person's eyesight.

我的正常視力自然是2080，也就是說，在沒有任何矯正的情況下，我看到的東西只有20英尺遠，就像正常人的視力其實是80英尺遠一樣。

And so I've been wearing contact since I was 12 years old in order to see clearly if you wear contact lenses, too.

所以我從12歲開始就戴上了隱形，為的是看清楚你是否也戴了隱形眼鏡。

But you find yourself dreading your annual appointment to renew your prescription, just like I always have.

但是，你發現自己害怕每年的約會，更新你的處方，就像我總是這樣。

You should know that simple contacts can really help you out.

你應該知道，簡單的聯繫方式真的可以幫助你。

Simple contacts lets you renew your expired contact lens prescription and reorder your brand of lenses online.

簡單美瞳讓您更新過期隱形眼鏡處方，並在線重新訂購您的品牌鏡片。

Within minutes, they bring the doctor's office to wherever you currently are.

幾分鐘內，他們就能把醫生的辦公室帶到你目前所在的地方。

You could take the simple contacts vision test online in five minutes.

你可以在網上進行簡單的隱形眼鏡視力測試，5分鐘就可以完成。

A real doctor will review it and if your vision hasn't changed, renews your prescription to.

真正的醫生會進行復查，如果你的視力沒有變化，就把你的處方更新到。

And if you have an unexpired prescription, you just upload a photo of it or your doctor's info and then order your lenses within minutes.

而如果你有未過期的處方，你只需上傳一張照片或醫生的資訊，然後在幾分鐘內就可以訂購鏡片。

Simple Contacts offers every brand of lenses with extremely reasonable prices.

Simple Contacts以極其合理的價格提供每個品牌的鏡片。

The prescription is only $20 compared to an annual appointment, which can be up to $200 without insurance.

相對於一年一次的預約，沒有保險的情況下，處方只需20元，而一年的預約則高達200元。

They have some of the best prices on contacts, and the shipping is free.

他們有一些最優惠的價格在接觸，和航運是免費的。

But best of all, you can get $20 off your first order right now by clicking the link in the description at simple contacts dot com slash real life floor or by entering the code real life floor at check out.

但最重要的是，你現在可以通過點擊描述中的鏈接在簡單的聯繫人點com斜線現實生活地板或在結賬時輸入代碼現實生活地板獲得20美元的折扣。

It's important to mention, though, that this isn't a replacement for your periodic full eye health exam.

但需要提到的是，這並不能代替你定期的全眼健康檢查。

You still need those, but this is the most convenient way that I've seen to renew a prescription and reorder your contacts.

你仍然需要這些，但這是我見過的最方便的方式來更新處方和重新訂購你的隱形眼鏡。

If your vision hasn't changed so once again, help support real life floor by checking out simple contacts and get $20 off by following the link in the description or by using the code real life floor at check out.

如果你的視力還沒有改變，所以再次幫助支持現實生活地板，檢查簡單的隱形眼鏡，並獲得20美元的優惠，通過以下描述中的鏈接或使用代碼現實生活地板在結賬。