"I'm not afraid of your jokes, it's the first time I've heard the word Europa." Sun Zhongyong said with a smile.

"But is there really a chance that life will exist on the planet Europa? Didn't you mean it was a very cold puck? ”

These days, the Mars base is quite lively.

The news that Chen Mengchuan and others decided to prepare a spacecraft to go to Europa soon spread throughout the Mars base.

"Europa is indeed a planet with possible life, but the exact form of life will only be known if you arrive in Europa and go to the field to explore. The most likely is the presence of some extremophiles. Chen Mengchuan replied to Sun Zhongyong's words.

Europa is a special planet, and its habitat may be similar to the hydrothermal vents of the deep sea on Earth or Lake Vostok in Antarctica, and if there is life, its life form may be similar to that of some polarophiles on Earth.

Whereas, extremophiles are organisms that can grow and reproduce in extreme environments, usually single-celled organisms. The extreme environments here, which are defined as anthropocentric, are very ordinary to the creatures themselves. That is, strictly speaking, these "extreme environments" are places where some organisms can live, whether humans consider these places to be ordinary or extreme.

To give an example, humans can be classified as mesophilic aerobic organisms.

Ordinary people don't know much about this kind of creature, so it's normal for Sun Zhongyong not to understand. Even Chen Mengchuan himself doesn't know much about this kind of creatures and this kind of extreme environment.

"Polarophiles? Could such a creature really exist? Sun Zhongyong is obviously very unfamiliar with these.

Chen Mengchuan smiled, raised his hand and smiled at a tanned middle-aged man beside him, and said, "If you want to ask this question, you have to ask Dr. Li." ”

Dr. Li Xiaosong, who has short hair and inch head, wears glasses with fixed straps, and his not tall body looks very thin and shy.

"There are such life forms." Li Xiaosong spoke.

"Most of the life forms that exist on Earth can be classified under the discipline of aerobic biology. Humans, birds, fish, and most fungi are aerobic organisms, which use the chemical reaction of oxygen to break down sugars and fats, and obtain energy to support the existence of life forms. ”

"The opposite of aerobic organisms is anaerobic organisms, and we usually refer to organisms that do not require oxygen to grow, but there are not many of them. It can be roughly divided into three types, obligate anaerobic organisms, facultative anaerobic organisms, and aerobic resistant anaerobic organisms. ”

"The expertise in this area is still relatively deep." Li Xiaosong said this pause.

"Let's talk about it, Dr. Lee, we don't know much about these things." Chen Mengchuan smiled, he knew the reason why Li Xiaosong stopped, and a lot of professional knowledge was very unpopular, so it wasn't necessarily interesting.

Li Xiaosong hesitated slightly, considered the language for a while, and then said again: "Then I will briefly introduce it." ”

"As I mentioned earlier, there are generally three types of anaerobic organisms. One is obligate anaerobic organisms, which are more extreme, and many anaerobic organisms will die quickly if exposed to an environment with oxygen. Obligate anaerobic organisms mostly survive by fermentation or anaerobic respiration. Once in contact with oxygen from the air or surface, obligate anaerobic organisms become deficient in superoxide dismutase and catalase, which are lethal superoxides that can help remove obligate anaerobic organisms from their cells. A small number of them survive, but most of them die quickly. ”

"There are many obligate anaerobes in some fungi, such as actinomycetes, clostridia, macrobacterium, Fusobacterium, digestive streptococcus and so on."

"Facultative anaerobic organisms and aerobic anaerobic organisms are some organisms that can survive in both aerobic and anaerobic environments, the difference is that aerobic anaerobic organisms do not use oxygen as the final electron recipient, which is a relatively unpopular knowledge, and it will involve many professional knowledge points, I will not go into details."

Li Xiaosong's words were very popular, and Sun Zhongyong basically understood them.

"Dr. Li, from a professional point of view, do you think there will be these creatures on Europa?" Sun Zhongyong asked him directly.

"Life science is more rigorous, and there may be many forms of life that we don't know, so whether this Europa will exist in life or need actual observation and scientific research to be able to make an accurate judgment, my personal point of view, or more biased, after all, this will also be a guess that everyone is looking forward to."

Li Xiaosong's speech is very distinctive, the rhythm is stable and his words are quite humble, which sounds more comfortable.

"I hope there really is the kind of life on this Europa that you said."

"If there really is a large amount of liquid ocean under the ice, the chances of life are very high. Among the polarophiles, there is also a species called psychrophiles, which are able to maintain the ability to grow and reproduce in a cold environment. ”

"Unlike other organisms, psychrophilic organisms have many different metabolic methods, such as photosynthesis, chemoautotrophics, heterotrophs, and the formation of robust, diverse populations. Most psychrophilic organisms belong to bacteria or archaea, and they are also widely distributed in the lineage of microorganisms. Because the temperature of the planet Europa is far from the sun and affected by Jupiter's gravity, it can receive very little solar wind radiation, and such low temperature conditions are actually very suitable for the survival of many psychrophilic creatures. ”

Li Xiaosong's words made Sun Zhongyong's eyes light up slightly: "Haha, I now believe that there will be life on this Europa, maybe there is still a colorful underwater world under the ice." ”

"A lot of astrobiologists, they think that Europa is life, because if you look at the tardigrade species on Earth, many tardigrade species can survive in outer space. There are also many orthodox scientists who speculate that the Tardigrade species themselves are species that came to Earth from outer space. Li Xiaosong said slowly.

"And creatures that can survive in outer space?" Sun Zhongyong was a little unconvinced.

Li Xiaosong nodded: "Yes, such as the tardigrade, this tardigrade, is very small, but it is indeed an animal." And there are many varieties, there are nearly a thousand species known, because the individuals are too small, most of them are not more than 1 mm, so it is generally difficult to notice them, but in fact, they can be found everywhere, some freshwater sediment, moist soil and bryophytes can be found in the water film. ”

"I know water bears!" An immature voice suddenly interjected, it was Sun Zhongyong's daughter.

Sun Zhongyong looked down at his daughter: "You also know? ”

"Dad, you are really uneducated, of course I know, my mother knows, my sister knows, but you don't know. The small column under the sea has introduced water bears! "The girl's voice is very tsundere.

"It's really lonely, can this tardigrade really survive in outer space?" Sun Zhongyong muttered and looked at Li Xiaosong.

Li Xiaosong nodded in confirmation: "Water bears can truly survive in the outer space environment." ”