Could we survive prolonged space travel? - Lisa Nip

譯者: Helen Chang 審譯者: S Sung

Prolonged space travel takes a severe toll on the human body.

長時間在太空旅行 會嚴重損害人體健康。

Microgravity impairs muscle and bone growth,

微重力削弱肌肉和骨骼的生長，

and high doses of radiation cause irreversible mutations.

高劑量的輻射造成不可逆轉的突變。

As we seriously consider the human species becoming space-faring,

當我們認真考慮人類 旅遊或居住於太空時，

a big question stands.

一大問題凸顯了出來。

Even if we break free from Earth's orbit

即使我們能掙脫了地球的軌道，

and embark on long-duration journeys among the stars,

並長時間穿梭旅行於星星之間，

can we adapt to the extreme environments of space?

我們能夠適應極端的太空環境嗎？

This won't be the first time that humans have adapted to harsh environments

這不是第一次人類 適應了惡劣的環境，

and evolved superhuman capabilities.

並演變出超人的能力。

Not fantastical powers like laser vision or invisibility,

不是指雷射視力或隱形等 荒誕不經的超能力，

but physiological adaptations for survival in tough conditions.

而是在艱難的條件下 生理適應並且生存的能力。

For example, on the Himalayan mountains

例如，在喜馬拉雅山脈

where the highest elevation is nine kilometers above sea level,

那裡最高的海拔是海平面上九公里，

an unacclimated lowland human will experience symptoms of hypoxia,

未適應的低地人會經歷缺氧的症狀，

commonly known as mountain sickness.

俗稱「高山症」。

At these altitudes, the body usually produces extra red blood cells,

在這樣的高度，通常身體會 產生額外的紅血球，

thickening the blood and impeding its flow.

使血液濃稠而阻礙其流動。

But Himalayans who have lived on these mountains for thousands of years

但已在喜馬拉雅山 安居數千年的居民，

permanently evolved mechanisms to circumvent this process

他們永久進化的機制並無這過程，

and maintain normal blood flow.

而是保持正常的血流量。

Cases like that prove that humans can develop permanent lifesaving traits.

類似這樣的例子證明，人類能夠 發展出永久性的救生特質。

But natural adaptation for entire human populations

但是，全人類族群的自然適應

could take tens of thousands of years.

可能需數萬年之久。

Recent scientific advances may help us accelerate human adaptation

近期的科學進步或能幫助我們 加速人體的適應期

to single generations.

縮短至一代。

To thrive as a species during space travel,

為使人類物種在太空旅行期間興旺，

we could potentially develop methods

我們或能開發新方法

to quickly program protective abilities into ourselves.

快速設定自我保護的能力。

A beta version of these methods is gene therapy,

「基因治療」測試版的方法，

which we can currently use to correct genetic diseases.

目前已被用於矯正遺傳性疾病。

Gene editing technology, which is improving rapidly,

基因編輯的技術迅速改善，

allows scientists to directly change the human genome

使科學家能夠直接置換人類的基因，

to stop undesirable processes or make helpful substances.

阻斷不良的過程或製出有益的物質。

An example of an unwanted process

一個不良過程的例子

is what happens when our bodies are exposed to ionizing radiation.

發生在我們的身體 暴露於電離輻射之下時。

Without an atmospheric barrier and a magnetic field like Earth's,

沒有像地球一樣的 大氣層和磁場的屏障，

most planets and moons are bombarded with these dangerous subatomic particles.

大多數行星和衛星 被危險的亞原子粒子所衝擊。

They can pass through nearly anything

那些粒子能夠穿透幾乎所有的東西，

and would cause potentially cancerous DNA damage to space explorers.

會損傷太空探險者的DNA， 並可能致癌。

But what if we could turn the tables on radiation?

但若我們將輻射轉敗為勝呢？

Human skin produces a pigment called melanin

人的皮膚產生 稱為「黑色素」的色素，

that protects us from the filtered radiation on Earth.

保護我們不受害於地球上那些 已被過濾的輻射。

Melanin exists in many forms across species,

跨物種存在許多形式的黑色素，

and some melanin-expressing fungi

有些真菌的黑色素

use the pigment to convert radiation into chemical energy.

以色素來轉換輻射成為化學能。

Instead of trying to shield the human body,

不是試圖屏蔽人體

or rapidly repair damage,

或是迅速修復損傷，

we could potentially engineer humans

而是策劃使人類

to adopt and express these fungal, melanin-based energy-harvesting systems.

採用和表現這些真菌 以黑色素為基礎的能量收集系統。

They'd then convert radiation into useful energy while protecting our DNA.

把輻射轉化成有用的能源， 同時保護我們的DNA。

This sounds pretty sci-fi,

這聽起來很科幻，

but may actually be achievable with current technology.

但以目前的技術而言， 或許實際上是可行的。

But technology isn't the only obstacle.

然而，技術並不是唯一的障礙。

There are ongoing debates on the consequences

目前對於激進改變遺傳結構的

and ethics of such radical alterations to our genetic fabric.

道德和後果的辯論正在進行中。

Besides radiation,

除了輻射，

variation in gravitational strength is another challenge for space travelers.

重力強度的變化 是太空旅行者另一挑戰。

Until we develop artificial gravity in a space ship or on another planet,

在我們成功地開發太空船 或其他星球的人造重力前，

we should assume that astronauts will spend time living in microgravity.

我們應該假定太空人 會生活在微重力的情況下。

On Earth, human bone and muscle custodial cells

在地球上，人類骨骼 和肌肉的保管細胞

respond to the stress of gravity's incessant tugging

對抗重力的曳引，

by renewing old cells in processes known as remodeling and regeneration.

「重塑」和「再生」老舊的細胞。

But in a microgravity environment like Mars,

但在像火星這樣的微重力環境下，

human bone and muscle cells won't get these cues,

骨骼和肌肉的細胞得不到這些提示，

resulting in osteoporosis and muscle atrophy.

因而造成「骨質疏鬆」 和「肌肉萎縮」。

So, how could we provide an artificial signal for cells

我們如何提供人工信號給細胞

to counteract bone and muscle loss?

以抵制骨骼和肌肉的損失呢？

Again, this is speculative,

臆測的說，

but biochemically engineered microbes inside our bodies

我們體內生化工程改造過的微生物

could churn out bone and muscle remodeling signaling factors.

能產出重塑骨骼和肌肉的信號因子。

Or humans could be genetically engineered

或者經由遺傳工程，人體可於

to produce more of these signals in the absence of gravity.

無重力情況下產生這些信號。

Radiation exposure and microgravity are only two of the many challenges

輻射暴露和微重力，

we will encounter in the hostile conditions of space.

只是許多我們面對不友善的太空環境 會遇到的挑戰中的兩個。

But if we're ethically prepared to use them,

但若我們合乎正道地使用

gene editing and microbial engineering are two flexible tools

基因編輯和微生物工程 這兩個靈活的工具，

that could be adapted to many scenarios.

它們可適用於許多的情況。

In the near future, we may decide to further develop

不久的將來，我們可能會進一步發展

and tune these genetic tools for the harsh realities of space living.

並調整這些遺傳工具， 以應付嚴酷現實的太空生活。