Dear Manager: I'm a student of NOmiddle school. I'm writing to you to tell you something about water pollution. There's a river near my village.
The water used to be very clean. People used to take water there. But this year, a paper mill opened there.
They poured waste water into the river, which made the river dirty. Because there was no drinking water, I Think you should bring some meat to stop the pollution.
Science and technology search for extraterrestrial life Sir Isaac Those telescopes that don't use reflection have a lens system, which Galileo first used to look at stars, but more than two centuries after Newton and Galileo, a man named Augustin Jean Fresnel's Frenchman invented a method to focus light, diffract a set of concentric rings, alternately transparent and opaque, tering and propagating light waves, so that they strengthen each other at a certain distance to form an image. These rings are called wave zone plates, and Laurent cochlin of the MIDI Pyrenees Observatory, who is a compatriot of Fresnel, thinks that the zone plates are hair Whether there is a way of life on other planets; to see oxygen in the atmosphere of another planet is a gift of biological activity, because the gas is very active and needs to be constantly updated, which almost certainly means that things like photosynthesis are going on, because there is no known abiotic process that can produce enough oxygen from ordinary substances, but here it is In an atmosphere, stars are so much brighter than the planets around them that their light will overwhelm the small amount of light reflected from the planet's suce, which is what the Fresnel telescope has, because the image of a telescope as big as a useful telescope will be a few kilometers away from the wave zone plate, so it has not been developed in the past But Dr. Kirklin is not worried because his Fresnel telescope will be in space, free from the interference of the earth's own atmosphere.
It will be able to separate images of alien planets, yze the light in their air, and examine the characteristic black lines in these spectra, which are caused by the absorption of some light by oxygen, a specific gas in the spectrum.
科学技术 寻找外星生命 寻找外星生命，艾萨克·牛顿爵士（Sir Isaac Newton）说，那些不使用反射的望远镜，它们有一套透镜系统，伽利略（Galileo）第一次采用这种方法来观察恒星，但在牛顿（Newton）和伽利略（Galileo）之后的两个多世纪后，一位名叫奥古斯丁·菲涅尔（AugustinJean Fresnel）的法国人发明了一种方法，可以用它来聚焦光线衍射一组同心环，交替透明和不透明，将散射和传播光波，使它们在一定距离之外相互加强，从而形成一个图像这些光环被称为波带板，菲涅耳的同胞，米迪比利牛斯天文台的劳伦特·科克林，认为波带板是发现其他行星上是否存在生命的方法；在另一个行星的大气中看到氧气是生物活动的一种赠品，因为这种气体非常活泼，需要不断更新，这几乎肯定意味着类似光合作用的事情在进行，因为没有一种已知的非生物过程能够从普通物质中产生足够数量的氧气，但是在这样一个大气中，恒星的亮度比环绕它们的行星要亮得多，以至于它们的光会压倒行星表面反射的少量光，而这正是菲涅耳望远镜所拥有的因为一个大到可以与一个有用的反射望远镜相媲美的望远镜所形成的图像将在离波带板几公里的地方，所以过去没有开发出这种技术，但科克林博士并不担心，因为他的菲涅耳望远镜将在太空中，不受地球自身大气层的干扰，它将能够分离外星行星的图像，对其空气中的光进行光谱分析，并检查这些光谱中的特征性黑线，这些黑线是由于部分光线被其中的特定气体氧吸收而引起的。
Scattered in the world's oceans are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small to be seen by the naked eye as they drift lazily along with the current, providing basic food for many of the larger animals. Plankton is described as the equivalent of grass growing in dry places.
However, plankton far exceeds the land grass estimated by one scientist. Although the world's grass produces about one billion tons of valuable carbohydrates every year, the amount of plankton in the ocean is more than twice that of the ocean. Despite its huge food potential, until recently, we planted grass on land The impact on plankton is very small, and now marine scientists are finally beginning to study this possibility, especially when marine resources become more important as a means to feed the growing world population, no one seriously believes that "plankton Burger" may soon become a possible agricultural supplement food source around the world, and plankton is in the Ocean There has been great interest among scientists.
One plankton that seems likely to harvest is a small shrimp like organism called krill, which grows to two to three inches long. Krill provides the main food for the great blue whale, the largest animal ever on earth. It's not surprising to realize that this kind of whale may reach maturity, and each shrimp eats more than a ton of krill a day.