Earth has been in danger? In order to protect human civilization from being destroyed, it has repeatedly contended with the universe
Have you ever thought about such a question, how many threats are facing the earth in the universe? Many people think that the biggest threat to the earth may be comets and meteorites. In fact, this is not the case. The probability of such a thing happening is very low. In fact, the greatest threat to the planet may come from our own homeland.
Mars
Asteroids don't usually orbit close to Earth, and most are confined to the zone between Mars and Jupiter, but Jupiter's massive mass disrupts the asteroid's orbital motion, occasionally pushing one of them toward the sun, and threat to the security of the earth. The threat to Earth may also come from comets, which threaten Earth not from Jupiter but from passing stars.
Jupiter
The Milky Way is not static. As the stars in the Milky Way orbit around the center of the Milky Way, the Milky Way itself will rotate slowly. It takes about 200 million years for the sun and its planetary entourage to revolve around the center of the Milky Way. In the process they encounter many dangers. Nearby stars may skip the nebula, displacing some stars toward the solar system. When a comet rushes into the inner solar system, the sun will evaporate some volatile or unstable material, and the solar wind will blow it into a long streamer, which is the famous comet tail.
Comets are mostly composed of carbon dioxide and organic molecules
In extremely rare cases, comets will collide with the earth during their stay in the inner solar system. On the surface, the comets have caused damage to the earth, but in fact the culprit is those passing stars. Fortunately, due to the enormous distances between the stars, such encounters are rare. Other celestial bodies may also cross the orbit of the solar system on the way around the center of the Milky Way, such as wandering planets, neutron stars, brown dwarfs, and black holes.
endless universe
All of these objects could strike Earth without warning and out of sight and wreak havoc on the solar system. Some astronomers think the sun may belong to a binary star system like many other stars in the Milky Way. And this half-star, which we call the Nemesis Sun, periodically disturbs the distant cometary cloud and sends some comets crashing into Earth, creating comet storms with devastating effects. Geologists have found that this large-scale ecological destruction shows a certain periodicity, which occurs about once every 30 million years.
binary system
In the depths of the universe, astronomers have observed galaxy systems in the apparent collision process. How likely is it that the Milky Way will collide with another galaxy? The presence of some fast-moving stars suggests that the Milky Way may have collided with and destroyed a smaller nearby galaxy. However, the collision of two galaxies does not necessarily bring disaster to the stars in their galaxies, because the stars in the galaxies are very rare, and they may come close to each other, but they will not directly collide. In contrast, the current ecological degradation, climate change, and small changes in the sun's heat output have made the earth extremely fragile, all of which are caused by humans. Although these changes are not enough to threaten humans, they will make our life extremely comfortable. disappear completely.