Jupiter's orbit change makes Earth more habitable? The interaction between celestial bodies is really amazing

In the latest study, researchers found that if Jupiter's orbit changes, Earth may become more habitable than it is now. Originally, researchers created a solar system model based on known solar system data and found that if Jupiter's position remains unchanged, but its orbit becomes more eccentric, Earth's orbit will also change accordingly, that is, some areas will sometimes be closer to the sun, and areas of Earth currently below freezing will become warmer and more habitable.

In fact, in the universe, driven by gravity, various interactions occur between celestial bodies all the time, sometimes repelling each other, sometimes attracting each other, and sometimes even "intimate contact". Let's take a look at some typical examples that are amazing or hilarious.

You and I look forward to Halley's Comet

In 1705, Edmund Halley, a professor at Oxford University, published "An Introduction to the Literature of Cometary Objects", which recorded the parabolic orbits of 24 comets observed from 1337 to 1698. He found that three comets appeared in 1531, 1607 and 1682, and their orbits looked exactly the same. Although the time when they passed the perihelion differed by nearly a year in the cycle, it could be explained as the gravitational perturbation of Jupiter or Saturn. So a thought quickly flashed through his mind: these three comets might be the three returns of the same comet!

But Halley did not come to this conclusion immediately, but searched for earlier records tirelessly. Sure enough, he found records of great comets in 1456, 1378, 1301, 1245... until 1066.

You know, in Halley's time, no one realized the common astronomical knowledge today - due to the gravitational force, comets will be "attracted" by the sun and move in a periodic orbit. Since Halley came up with that bold idea, he has been very interested in observing and studying comets. After a lot of observation, research and calculation, he boldly predicted: "The comet that appeared in 1682 will return again in late 1758 or early 1759."

Halley was nearly 50 years old when he made this prediction. He realized that he might not be able to witness the comet's return, so he said with a humorous and slightly regretful tone: "If the comet did return in 1758 according to my prediction, fair future generations would probably not refuse to admit that it was first discovered by an Englishman."

Sixteen years after his death, in 1758, the comet returned as expected, shocking the scientific community and the public, and instantly dispelling all doubts. As the first comet to be successfully predicted to return, it is now called Halley's Comet.

The last time Halley's Comet was observed "closely" by humans was from 1985 to 1986, and its orbital period is about 76.1 years. The next time you and I will be lucky enough to see Halley's Comet pass through perihelion will be in 2061.

Halley's Comet

Of course, with the vigorous development of aerospace technology, perhaps humans will not have to wait until that time to actively "visit" Halley's Comet by driving spacecraft and experience the wonders of celestial gravity.

The strange "three-body" movement

A few years ago, American astronomers discovered the magical "three-body" star system, which includes an ultra-high-density pulsar and two white dwarfs.

Astronomer Jason Boyle first discovered an unusual pulsar during a large-scale sky survey using the Green Bank Telescope in 2012. When he made precise measurements of the pulsar's rotation speed, he determined that it had a complex orbit. In this case, the only explanation was that there were two more white dwarfs, which meant that he had discovered a "three-body" system.

The famous science fiction novel "The Three-Body Problem" describes the complex structure of galaxies: when there is only one star in the galaxy, the planet will make regular orbital motion around the star under the influence of gravity; if one more star is added, a stable binary star system will be formed, which will also form a stable celestial orbit; but if there are three or more stars in the galaxy, the complex gravitational forces between them will produce a combined force, causing the star to be sometimes attracted and sometimes repelled, thus presenting a complex orbital motion, and the planet will be "at a loss" and face disaster.

With the current level of human astronomy and mathematics, the "three-body" problem cannot be strictly solved. Therefore, when studying complex celestial motion, it is necessary to use various approximate solutions according to the actual situation. Generally speaking, the "three-body" problem can be roughly studied by analytical method, qualitative method and numerical method, each of which has its own advantages and disadvantages. In order to solve the fundamental problem, the exploration of new integrals and the improvement of various methods have always been an important topic in the study of the "three-body" problem.

Of course, these studies rely on progress in basic science and are destined to be a long process. Let us try to solve the problem before the Three-Body fleet sets out to find a new home.

Watch out! Earth and Earth Collide

The 1998 science fiction film "Armageddon" tells the inspiring story of humanity's resistance to extraterrestrial threats. An unknown celestial body is approaching the Earth. Scientists have calculated that it weighs about 500 megatons and has a cross-sectional area equivalent to the size of New York City. It is "bound" by the sun's gravity and orbits the sun. However, according to its orbit, it will collide with the earth in about a year, with enough power to destroy humanity. In order to save themselves, humans launched a special spacecraft to try to land on the celestial body, use special drilling equipment to open a tunnel to the core, and then put in a nuclear device to detonate it, causing it to disintegrate into several small pieces, helping humans escape.

In fact, celestial body collisions are very common in the universe. According to the law of universal gravitation, the gravity of a celestial body with a larger mass will affect the trajectory of a celestial body with a smaller mass, making its orbit closer to itself, or even directly "capturing" it, thereby increasing its own satellites.

However, the joy of a large celestial body may turn into sorrow. Especially if the surface of the large celestial body is covered with a thick atmosphere, the small celestial body will encounter friction resistance every time it passes by, and will also lose kinetic energy, causing the orbital altitude to further decrease. Over time, the small celestial body is likely to collide with the large celestial body.

Having an atmosphere to protect it is a good thing after all. The moon lacks an atmosphere. In its long history of evolution, the lunar surface has long been riddled with holes by various "passers-by" in space. The Earth is lucky. Because it is covered with an atmosphere at an altitude of more than 1,000 kilometers, most of the "extraterrestrial visitors" that rush to the Earth will be burned up before landing. Even so, according to incomplete statistics, there are still as many as 190 large craters on Earth.

Many scholars believe that it was the chain reaction caused by the asteroid impact that led to the Cretaceous-Paleogene extinction event, which caused the dinosaurs that dominated the Earth for more than 150 million years to meet a tragic end. Some even suggest that the formation of the Earth and the Moon was the result of violent collisions, mergers, and splits of celestial bodies billions of years ago.

Fortunately, in reality, humans are working hard to resist the threat of asteroids. On April 24, China's Space Day, China announced that it would start to build a near-Earth asteroid defense system to contribute to the protection of the Earth and human safety.

On September 26, about 11 million kilometers from Earth, the American DART spacecraft, which is similar to a vending machine, will hit an asteroid with a diameter of 160 meters at a speed of 6 kilometers per second in an attempt to change its orbit. This upcoming "violent" action will also be the first "field" test of a planetary defense mission in human history.

Schematic diagram of the US DART spacecraft impacting an asteroid

In short, the interactions between celestial bodies are complex and subtle. On the one hand, they have accumulated valuable data for scientists to study celestial mechanics and astronomical phenomena, and promoted the progress of basic technology. On the other hand, they will also make us cherish the blue planet we live on even more. (Author: Yan Jiawei)