Astronomical encounters may have played a more serious role in the formation of the solar system, Earth's orbit, and the living environment than we have hitherto thought. the Astrophysical Journal LettersAccording to a recent study published in Millions of years ago He had an opinion on the orbits of the planets.
Space is mostly empty and there are vast distances, but the Milky Way is a populated and noisy galaxy, with stars moving in different orbits and at different speeds, which can come closer to us from time to time.
This is important because geographical data show that deviations in the Earth's orbit have caused atmospheric anomalies, and it would be important to know the Earth's orbit during such episodes.
– noted the author of the research, Nathan Cape, a scientific researcher at the Planetary Science Institute.
Another player in the fateful showdown may have been the Sun-like star, HD-7977, which passed close to the solar system 2.8 million years ago. The distance between it and the sun was 31,000 astronomical units, or 31,000 times the distance between the sun and Earth. According to less conservative estimates, the star could be much closer, by up to 4,000 AU.
The giant planets in the solar system, Jupiter and Saturn, exert a dangerous gravitational influence on Earth. According to Cape's calculations, HD-7977's impact was indirect and primarily affected our planet by interfering with the movement of giants. The resulting changes occurred over millions of years.
That won't be the case
Such encounters may not be rare. On average, the Sun approaches a star by 50,000 AU every million years, and a more intimate encounter occurs at a distance of about 10,000 AU every 10 million years.
Cape and his colleagues found that by projecting this trend back, similarities can be found between past encounters and changes in Earth's climate. An example of this could be the geohistorical event called the Paleocene-Eocene thermal maximum 55 million years ago, when thousands of gigatons of carbon were released into the atmosphere, and the average temperature rose by 8 degrees, and the temperature in Antarctica was 15 degrees, and the sea was 40 degrees off the coast of Africa. According to experts, this can be explained by a collision event that made the planet's orbit extreme and unpredictable.
Going back to the history of the solar system, of course, there is more and more uncertainty in the story. Currently, HD-7977 is the only planet that has clearly come close to the solar system. According to experts, it is in any case important to take the interstellar environment into account in models used to describe Earth's evolution.
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