科學(xué)60秒: 披上"黑色外套"的地外植物
來(lái)源:滬江聽寫酷
2011-08-06 10:00
Most plants capture sunlight. And the results are usually green. Because in photosynthesis, plant chlorophyll uses [--1--] of blue and our sun’s abundant red, and reflects green. But what if—as many [--2--] suggest—there’s an Earth-like planet with multiple suns? Researchers at England’s University of Saint Andrews say that photosynthetic life on such a planet might end up as a [--3--] black or gray. Or even with a high SPF.
A quarter of all stars like our sun actually exist in multi-star systems. Plants on a planet with two sunlike stars could need protection against too much radiation—they might evolve their own [--4--] sunscreens.
Or a planet with two stars may have one sun-like star, along with a red dwarf star that’s also common in multi-star systems. Any photosynthetic life would be adapted to take advantage of the available light waves.
Plants that relied at times mostly on the dim red dwarf might need light from all across the visible [--5--]. They wouldn’t reflect any wavelengths, so they'd appear black. These ideas were presented at the current Royal Astronomical Society meeting. So for healthy eating on some other planets, try the leafy dark salad.
【視聽版科學(xué)小組榮譽(yù)出品】
A quarter of all stars like our sun actually exist in multi-star systems. Plants on a planet with two sunlike stars could need protection against too much radiation—they might evolve their own [--4--] sunscreens.
Or a planet with two stars may have one sun-like star, along with a red dwarf star that’s also common in multi-star systems. Any photosynthetic life would be adapted to take advantage of the available light waves.
Plants that relied at times mostly on the dim red dwarf might need light from all across the visible [--5--]. They wouldn’t reflect any wavelengths, so they'd appear black. These ideas were presented at the current Royal Astronomical Society meeting. So for healthy eating on some other planets, try the leafy dark salad.
【視聽版科學(xué)小組榮譽(yù)出品】
wavelengths
sci-fi scenarios
drab
UV-blocking
spectrum
披上"黑色外套"的地外植物
大多數(shù)植物在陽(yáng)光的照射下, 吸收藍(lán)光和紅光波長(zhǎng),通過(guò)葉綠素進(jìn)行光合作用, 并使葉子呈現(xiàn)綠色. 但是如果--就像科幻小說(shuō)里寫的那樣--一個(gè)類地行星周邊圍繞著幾個(gè)太陽(yáng), 又會(huì)是怎樣一番光景呢? 英國(guó)圣安德魯大學(xué)的研究人員表示,在這樣的行星上, 植物的光合作用結(jié)果只會(huì)是呈單調(diào)的黑色或者灰色, 甚至是更深的顏色. [注1]
在聚星系[注2]中, 有四分之一的恒星與我們的太陽(yáng)類似. 而有兩顆太陽(yáng)照射的行星上的植物則需要進(jìn)化自身的紫外線阻擋層來(lái)保護(hù)自己抵擋過(guò)多的紫外線.
有的行星有兩顆恒星, 但只有一顆類似太陽(yáng), 和聚星系中常見(jiàn)的紅矮星在一起. 依賴光合作用的生物則利用可用光波來(lái)適應(yīng)環(huán)境.
這種情況下的植物有時(shí)候會(huì)依賴昏暗的紅矮星發(fā)出的大部分可見(jiàn)光波. 由于它們不會(huì)反射波長(zhǎng), 因此呈現(xiàn)黑色. 此項(xiàng)推測(cè)發(fā)表在當(dāng)下的皇家天文協(xié)會(huì)的會(huì)議上. 如果有機(jī)會(huì)嘗試地外行星上的植物, 不妨試試黑色沙拉吧~
注1: 英國(guó)輻射防護(hù)委員會(huì)的一份研究報(bào)告指出,防曬作用最差的是淺黃色的棉織品,其防曬系數(shù)僅為 7 ,米色棉織品的防曬系數(shù)為 9 ,并且防曬系數(shù)隨著顏色的加深而增大。
注2: 銀河系中的星系多為單星系或雙星系,具有三顆以上恒星的星系被稱為聚星系,不太多見(jiàn)。