Every minute and every second, the ground beneath our feet is actually moving. It's just that we are too small, and the reference objects in space are too far away, so we mistakenly think that all the celestial bodies are orbiting us.
But no matter who runs it or not, for thousands of years, human beings have gradually summarized and formed a set of time systems according to the laws of the movement of the stars.
Even though astronomers now know that the Earth revolves around the Sun and the Sun revolves around the Milky Way, the system of calculating time and distance is still based on the Earth and the Sun.
In this way, a bizarre scene appeared. Because each celestial body moves faster or slower, the orbit of the celestial body around the star can also be large or small.
It is strange for a calculation system based on the earth to calculate the time of the movement of other celestial bodies. Even within the solar system, the eight planets travel at different times. And in the depths of the vastness of space, the difference in the operating time of other celestial bodies is even more eerie.
Let's take a look at the speed of the planets that orbit the stars.
The concept of orbital period
Before talking about these running planets, let's take a look at what the time system that calculates their orbit is. Our time, years, months, and days are all based on the rotation and revolution of the earth.
This is known as the Universal Time system, which falls under the category of calendar in astronomy. The time of the day is determined based on the time of the Earth's rotation, which is called the sidereal day in the field of astronomy.
We all know that a day is 24 hours, and the precise time of a sidereal day is 23 hours, 56 minutes and 4 seconds. The timekeeping basis of the month is determined by the time it takes for the moon to revolve around the earth.
When the Earth makes one revolution around the Sun, the average time it travels is known as the sidereal year. A sidereal year is 365 days, 6 hours, 9 minutes, and 9.5 seconds.
When a planet like the Earth orbits the Sun and returns to its starting point, the time it takes to travel is called the orbital period, which is also called the sidereal cycle or orbital period in astronomy.
Human exploration of outer space is gradually from the earth to the farthest, so the time and computing system are based on the earth's operation.
As a result, when there are planets in space with small or large orbits, their operating times are strange compared to the Earth.
A planet with an orbital period of more than 1 million years
The Earth orbits the Sun for 365 days, and astronomers have discovered many planets in the depths of the universe with orbital periods far beyond the years.
Before 2015, the longest orbital period was found to be 163,000 years, such an exaggerated orbital period was far beyond human imagination, but after 2016, astronomers found a longer time.
Since then, Australian astronomers have discovered planets with an orbital period of 1 million years. Yes, you heard it right, converted to the time system of the Earth year, the planet named 2MASS J2126-8140 would take 1 million years to circle the stars in its system.
Researchers have found that the planet, which has such a long orbital period, is composed entirely of gas. The main reason why the orbital period is so long is that it is so far away from the star.
It has been calculated that the planet is more than 1 trillion kilometers away from the star, which is 140 times farther than Pluto to the Sun.
In the eyes of astronomers, it is quite rare for a planet to be so far away from its parent star. The planet is about 100 light-years away from Earth, which was accidentally discovered by astronomers while surveying young stars closer to Earth.
The planet, as well as the orbiting stars, was formed in a very short time, about 10 million to 45 million years.
Moreover, the orbit of the planet is not stable, and its bond with the star is relatively weak. That is to say, if other celestial bodies enter its range of activity, it will change the orbit of the planet, and the gravitational pull will directly pull it out of the range of the star's control.
Do you think this is the planet with the longest orbital period, but there are even longer? A planet named COCONUTS-2b has an orbital period of more than 1.1 million years.
Because it is more than 6,000 AU away from its parent star, astronomers thought it was a wandering object without a parent star when they first discovered it.
But in reality, it has a mother star, and its mass is not much different from the latter, so the gravitational pull of each other is still there, which is why it is so far away that it can still circle the star.
Whether it's 1 million years or more than 1.1 million years, such a long time, if there are civilizations on the planets, their calendars and timekeeping systems must be different from ours.
However, from the perspective of the earth, a planet so far away from the star will definitely not feel light on its surface, so no matter how old the time is, the harsh environment is not suitable for life in the first place.
Going back to the revolution cycle, there are those with long running time and some with short running time, which are shorter than you can imagine.
The orbital period of the planet Π is only 3.14 days
In 2020, astronomers at the Massachusetts Institute of Technology discovered the planet with the shortest orbital period. The planet, named K2-315B, is similar in size to Earth, as its radius is only 0.95 times larger than Earth's.
Although similar in size to Earth, it has a short orbital period, taking only about 3.14 days per orbit of its parent star.
This means that its orbit is small and it is very close to its parent star. According to astronomers, the stars it orbits are only one-fifth the mass of the Sun and are low-mass cold stars.
But even so, due to the close proximity to the star, the temperature on the planet's surface is still very high. It has been estimated that the surface temperature can reach 177°C. So by the standards of the earth, this is also a planet that will not have life.
In fact, what is even more peculiar is that its orbital period is similar to pi, so it was later called the planet Π. As for whether this value is a coincidence, or whether there is some intrinsic relationship, it remains to be further studied by the scientific community in the future.
The orbital period within the solar system
Let's look back at the solar system, where in addition to planets like Earth, a large number of asteroids are also orbiting the sun.
In 2019, astronomers discovered an asteroid with the shortest orbital period, with only 151 days per orbit of the sun.
The asteroid was named 2019 LF6 after its appearance, and it belongs to one of the Adina asteroids in the solar system. All asteroids orbiting the Earth are classified as part of the Adina Asteroid Series.
So far, astronomers have discovered 20 Adina asteroids. From an observational point of view, all Adina asteroids have a very short window of observation on Earth, and they can only be found within half an hour before sunrise or after sunset.
Because they are so difficult to observe, astronomers believe that there should be a large number of similar asteroids scattered within the Earth's orbit.
Prior to the discovery of LF6 in 2019, the asteroid with the shortest orbital period in the solar system was 2019 AQ3, which orbited the Sun for 165 days.
Through these new discoveries, we can see that there are not only planets such as the Earth orbiting in the solar system, but also a large number of asteroids orbiting the sun.
There are so many of these asteroids, and so far about 100 have been found closest to Earth. In addition, between Jupiter and Mars, there is a relatively large asteroid belt, with 2,000 asteroids that have been discovered.
Compared to planets such as Earth, asteroids have fixed orbits, but they are affected by the gravitational pull of other large bodies. Due to the different speeds of each asteroid, the orbits are not parallel but three-dimensional, so some asteroids will collide with them due to gravitational attraction when they approach the range of a planet.
The meteors we see at night are asteroids that are pulled by the Earth's gravity. It's just that most of them are very small, and they don't have them after rubbing against the atmosphere during the fall.
However, if a large planet deviates from its orbit and enters the Earth's range, the consequences of a collision are difficult to predict. Because of this, astronomers monitor asteroids closely, just to prevent any "stunned" from coming uninvited.
When we look at a close-up photo of the Moon, there are craters and craters everywhere, which are actually formed after being hit by various asteroids in history.
As a result, some people can't help but wonder again: Do all the stars in the universe orbit around planets or asteroids? Isn't there a star where the planet doesn't exist?
About sixty percent of stars have planets
Astronomers have considered this question for a long time, and at one time thought that there were not many models with planets like the solar system. But this is not the case.
In 2008, astronomers discovered that the pattern of planets orbiting stars is common in the universe.
According to previous rough estimates, 60% of the stars currently known have planets that accompany them. The exact value is not clear, but it seems to astronomers that the percentage is high.
This means that there are more than 100 billion star systems like the Sun in the Milky Way alone. With such a huge system, there are countless planets in it. Theoretically, there is a high probability that there will be life on extraterrestrial planets or even advanced civilizations.
epilogue
From the perspective of human beings, the earth revolves around the sun, and the time of year does not change, which is a truth that cannot be subverted. And when you come to the vast deep space of the universe, other planets orbit their own stars, and they all have their own time to follow.
Essentially, they all operate in the same mode, but because of the difference in time and speed, there will be a lot of differences. Assuming that extraterrestrial civilizations are common, everyone lives on their home planets, following each other's laws.
And this unbreakable law seems to have become a shackle that hinders mutual communication. It not only forms a barrier in distance and space, but also sows a barrier in the heart of life. After all, no matter which planet life looks at the universe from afar, its location seems to be the center.
Resources:
"The farthest planet from the star is discovered: the orbital period is 1 million earth years", China News Network, January 28, 2016
"Earth-sized "π planet" orbital period of about 3.14 days" Science and Technology Daily, September 23, 2020
"The Fastest Asteroid Around the Sun: Only 151 Days in a Year" Xinhuanet, July 17, 2019