Where does nitrogen come from on earth? A new study from Rice University in the United States shows that the original source of nitrogen is "close at hand". According to the network of physicists on the 21st,The isotopic characteristics of nitrogen in the iron meteorites indicate that the earth may collect nitrogen not only from the outer solar system outside the orbit of Jupiter, but also from the protoplanetary dust tray of the inner solar system.
Nitrogen is a volatile element, like carbon, hydrogen and oxygen, which makes life possible on earth. Knowing its origin is not only helpful to study the formation of rocky planets in the inner solar system, but also provides clues for the study of the dynamics of protoplanetary disks, and is of great significance to the study of the potential habitability of exoplanets.
Because the seeds of today's rocky planets (also known as protoplanets) grew in the inner disk through the accumulation of local dust, it was thought that they did not seem to contain nitrogen or other volatiles, which had to be obtained from the outer solar system. But the latest evidence clearly shows that only part of the nitrogen on earth comes from the outer solar system outside Jupiter.
In recent years, scientists have analyzed the non-volatile elements in meteorites and proved that the dust inside and outside the solar system has completely different isotopic compositions.
The researchers found that within about 300000 years after the formation of the solar system, the dust on the inner protoplanet has obvious nitrogen isotope characteristics. All the iron meteorites from the inner wall contain a low concentration of N 15, while the iron meteorites from the outer wall are rich in n 15. This shows that in the first few million years, the astrolabe was divided into two reservoirs, the outer layer was rich in nitrogen isotope 15, and the inner layer was rich in nitrogen isotope 14. From the beginning, these volatile elements existed in the dust pan, probably in the form of refractory organic compounds. This finding is contrary to current understanding.
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For life to appear on the planet, it needs compounds or volatile elements including carbon, nitrogen, sulfur, etc. Like other rocky planets, the earth does not contain volatiles. Previous theories suggested that nitrogen on earth came from the collision of distant ancient planets. These wonderful collisions release the essential elements of life. This time, the latest research of scientific researchers suggests that the source of nitrogen on earth may not be so far away, and the rocky planet itself may also carry volatile elements. People have been trying to figure out why the earth is what it is today. New ideas, new means and more sophisticated technology are all making us revise our previous cognition again and again.