Unexpectedly, on the day of the college entrance examination, "aliens" stole the spotlight. On a planet more than 300 million kilometers away from the earth, scientists found that there was a "source of life" - more than 20 kinds of amino acids were detected in samples collected on the planet. As we all know, protein is the material basis of all life on earth, and amino acids, as its basic unit, are naturally regarded as the origin of life.
As a result, this "evidence" in space detonated the whole network in an instant. The number of microblog readers has reached 420million, and the number of relevant questions has exceeded 3million.
Netizens have opened their minds, fast forward to the alien invasion of the earth, "interstellar love", "Ott nebula" and so on.
However, many people remain skeptical. One is that the sample size is too small and cannot be reproduced.
Another hot topic is the term "the source of life" of amino acids.
Is it possible that alien organisms are not necessarily composed of amino acids?
The sample is from an asteroid about 1km in diameter
This time, the sample was collected back to earth by an asteroid probe called "falcon 2".
Launched by the Japan Aerospace Exploration Agency (JAXA), it is the successor probe of the Hayabusa.
(the "predecessor" falcon is the world's first detector that brings back material from a small planet.)
Falcon 2 was launched in december2014 and met the 1999ju3 asteroid (Longgong, a near earth object with a diameter of about 1km) in June 2018.
Then it arrived at the star, started measuring and sampling, and finally left Longgong in november2019.
Source: Nikkei Asia
A year later, in December 2020, Falcon 2 successfully arrived on earth.
JAXA personnel obtained the sand and other materials it brought back from longgongxing in the desert of Australia.
There are two samples in total, totaling 5.4G, which is equivalent to 50 times of the expected sample mass (only 0.1g is expected).
One of the samples is the first underground material of an asteroid.
At that time, the project director also publicly stated:
The capsule containing the samples is in perfect condition.
Therefore, from 2021, JAXA and Japanese research institutions (including the University of Tokyo and Hiroshima University) started a comprehensive investigation and Research on this sample.
In these two days, a Japanese Education Ministry official said:
- "source of life" *:20 amino acids have been detected in the collected samples.
This discovery is the first proof that there are organic compounds outside the earth.
Samples collected by asteroid probe, source: Japan Aerospace Exploration Agency
Why can we say for the first time
Because one of the samples is the underground material of asteroids, it is basically not affected by sunlight, cosmic rays, and weathering.
Moreover, it was brought back directly and was not exposed to the outside air. It can be ruled out that the amino acid came from the earth.
(the previous samples were more or less disturbed by external air and other factors due to various conditions.)
Previous relevant studies
The emergence of extraterrestrial organic matter is the key to understand the existence of other life in the universe and the origin of life.
Among them, as the material basis of life on earth, protein is the key research object of scientists.
As early as half a century ago, scientists had an idea about its basic unit, amino acid.
In 1953, Miller and Yuri, two scientists from the University of Chicago, successfully converted inorganic substances into amino acids through simulation experiments. Today, it is still a classic experiment in textbooks. Later, 11 scientists repeated the experiment and directly obtained 22 kinds of amino acids.
In addition to producing amino acids, scientists have also completed experiments on the synthesis of peptides from molecular clouds.
According to the universe and earth science blogger @ Cambrian visitor , through vacuum simulation, scientists successfully synthesized various forms of polyglycine from carbon monoxide and ammonia molecules at minus 263 degrees Celsius, with chains of 10 or 11 subunits.
In addition to the idea of simulation synthesis, another big idea is detection of extraterrestrial substances .
In 1990, amino acids were detected in the acfer 086 meteorite in Algeria.
In 2017, scientists found ten new amino acids in the Murchison meteorite * that fell in 1969, and supplementary experiments showed that these amino acids could directly generate aldehydes and ammonia on the meteorite.
In 2020, scientists from Harvard and the two companies plex and brookko discovered proteins in meteorites for the first time.
They re detected the acfer 086 meteorite. Through mass spectrometry analysis, it was found that its glycine signal was stronger than that detected before, and it contained additional oxygen and lithium atoms.
Through model simulation, glycine formed a polymer similar to protein, which they named hemolithin**.
In addition to amino acids and peptides, scientists also start with organic molecules and RNA.
In 2021, astronomers studied that there may be a large number of extraterrestrial life in the Milky way. According to the science and technology daily, the protoplanetary disk drawn by them shows that it is full of 18 kinds of organic molecules, many of which are related to the origin of life on earth, such as nitrile.
Source: m.weiss/ Harvard and Smithsonian Center for Astrophysics
In March this year, scientists discovered the largest molecule ever discovered on the planet, with nine atoms.
As for the RNA direction, according to the information shared by @ Cambrian visitors, a recent experiment just showed that the genetic material RNA can be spontaneously formed on the basalt lava glass.
Basalt lava glass, a kind of material, exists on the surface of Mars as well as all over the earth.
The painting style in the comment area is bright
Finally, back to the study itself. This news about the existence of extraterrestrial sources of life has caused netizens to burst into flames, and even the painting style has gradually become outrageous.
There is a Altman wind : so Altman really exists. One day, we can reach the country of light!
There is the wind of lonely looking for objects : the scope of looking for objects has expanded. Maybe you can have an interstellar love! (manual dog head)
And the childhood "fantasy" of netizens has come true: I say there are aliens!
But there are also some serious comments.
Some people think this is expected. After all, the earth is a part of space.
Zhihu netizen @mhang said that the discovery of amino acids outside the earth is just a matter of time. However, it is difficult for amino acids to form complex protein structures and even organisms.
Some netizens believe that this is not good news.
Zhihu @ GuDi said that if life is really found outside the earth, it would be very bad for humans.
Of course, there is an optimistic attitude, @ Kop an old man thinks:
If the research conclusion of Falcon 2 is finally confirmed, it will have a disruptive impact on the previous research on the origin of life in the scientific community.
On the origin of life, scientists need to find another way.
In addition, in view of the previous academic impression of Japan, some netizens think it is better to let the bullet fly for a while~
Well, what do you think of the "discovery of the source of life outside the earth"?