We often say that the earth is like a huge universe spacecraft, carrying countless lives on it, and of course we humans ourselves are galloping in the universe.
but do you know? As the earth travels rapidly in the universe, the journey is very dangerous. There are many unknown risks that threaten the earth all the time, and of course there are life on it.
In the course of the birth of life on the earth, from about 500 million years ago to today, as far as we know, the earth has experienced at least 5 mass extinctions, each of which will cause at least 60% of the terrestrial life to be wiped out. Some of these extinction causes were caused by super volcanic eruptions, some were caused by the impact of asteroid , and some were caused by supernova eruptions. Among them, the most certain one occurred when the dinosaur was killed by the small planet 65 million years ago. Extinction event.
So what's next? Will the sixth mass extinction happen?
will definitely happen from the current point of view, but it is just a matter of time and method.
Because the universe is really dangerous, it wants to kill humans all the time. The extinction of human beings is not unforeseeable in science. The following five ways will easily lead to the mass extinction of life on earth again.
asteroid impact event
Asteroids in low-Earth orbits outside the Earth are the biggest threat to the Earth’s spacecraft. Most of them originated in the asteroid belt and were ejected into the inner solar system by Jupiter’s gravity;
began to near the Earth’s orbit Orbiting the sun, their orbital period is basically the same as that of the earth, and the orbits of some asteroids overlap with the orbit of the earth, which increases the risk of them hitting the earth.
So how big is their threat to the earth?
In our previous understanding, the space around the orbit of the earth orbiting the sun looks empty, very empty, and there is no danger.
In fact, this is our view angle is too small, if we stand outside the solar system , you would not think so.
The above picture is the map of known asteroids. If you look at it this way, you will find that there are too many time bombs hidden around the earth. And the earth around it is not as empty as we imagined.
The above picture more vividly shows the movement of asteroids during the 20-year period around earth orbit . There are currently more than 2,000 of these asteroids that pose a greater threat to the Earth. Here is a typical example of
, which is also an asteroid that has recently been thought to be likely to collide with the Earth in 2068: the star of destruction. The asteroid
was discovered in 2004. Its orbital period around the sun is 323.6 days, while that of the earth is 365.3 days. This period is quite close. If their orbital planes are close, the risk of collision will definitely be high. .
From the above picture (red is the ruin star, blue is the earth), it can be seen that before 2029, its orbital eccentricity is very small, but after the encounter with the earth in 2029, due to the gravity of the earth, the orbit will appear A relatively large change;
scientists calculated the orbit of this asteroid and estimated that the probability of it hitting the Earth in 2068 is 1 in 150,000.
However, its longest semi-major axis is only about 450 meters. If it really hits the earth, the energy released is equivalent to 50 times that of the Tunguska Big Bang, but an asteroid of this size will not destroy life on the earth;
must know that year The asteroid that hit the dinosaur was at least 10 kilometers in diameter. There are 1950DA asteroids, Benu asteroids, etc. near the earth's orbit besides the ruined planet, which are all threats to the earth.
Therefore, when the earth is carrying life through the universe, there are many dangers hidden around it. In the future, human beings will not be extinct with these asteroids, but no one knows, but it is certain that the asteroid will hit the earth.
If humans can survive asteroids, there are other dangers waiting for us in the universe.
gamma ray burst
The frequency ofgamma-ray bursts in the Milky Way is still relatively high, at least once every century, this is a very powerful energy eruption, the energy released instantly is equivalent to the energy released by the sun in a lifetime, and the brightness is very high. The reason for the
gamma-ray burst is very great, but the only thing we know for sure is that when two neutron stars merge, an energy jet will be produced. If it is aligned with the earth, strong electromagnetic radiation will instantly destroy the earth’s atmosphere. , and all electrical equipment.
The atmosphere, especially the ozone layer, is destroyed, and only extinction is waiting for mankind.
Fortunately, this kind of high-energy event can only pose a threat to the earth within 6000 light-years from the earth, and it must be aimed at the earth. The probability of
is greatly reduced.
Other celestial bodies broke into the solar system
The solar system shuttled in the Milky Way, but there are many wandering stars , stellar remains, planets and star-rated black holes in the Milky Way. These celestial bodies wander in the Milky Way without a fixed law of motion.
They will have a certain chance to approach the solar system or even cross the solar system.
For example, 70,000 years ago, a brown dwarf called the Scholz star passed through the Oort Cloud of the solar system. This was a failed star and the mass was not very large. Far, so there is no harm. If
is a large-mass star, or a small-mass planet, they will pass through the inner solar system, will disturb the orbit of the planets in the solar system due to the action of gravity, and even eject the planets out of the planetary system.
Although the probability of such an event is as low as one in a billion, if it does happen, the earth will freeze in a short period of time and humans will go extinct. Supernova
The picture above is a very famous Crab Nebula, which was produced by the explosion of a dead star in 1054 AD. At that time, humans witnessed the explosion of this star with their own eyes. The different elements in the
diagram show the presence of elements such as hydrogen, oxygen, and silicon. The energy released by the supernova explosion is also quite huge. If the earth was within 10 light years of this supernova at that time, then humans might be extinct. This supernova
is very rare, and its frequency is estimated to be once every 10 billion years.
If mankind can survive the above disasters, then the last disaster will definitely kill mankind.
Sun
The orange, purple, and green lines in the figure above represent the luminosity, radius, and temperature of the sun, respectively. It can be seen that from now to the future, its luminosity and radius will always increase, and the speed will become faster and faster.
According to estimates, in just 2 billion years, the energy output by the sun will increase to boil the sea water on the earth, and the whole earth will be out of control like Venus, and all life will be extinct.
Therefore, human time is actually limited, which is why human beings are now vigorously exploring outer space and considering interstellar migration, because any measures to protect the earth are only delaying the time for humans to leave the earth.
We don't want to see that before human beings have the ability to leave the earth, the earth has been destroyed by us to the point of being uninhabitable.
Therefore, we are in danger all the time when we live on the earth. These dangers warn us, protect the earth, and prepare to leave the earth.
