How do scientists determine that Kepler 452 is suitable for human migration?

By May 2028, humans have discovered 3,767 exoplanets. Among them, 77% were discovered through the transit phenomenon. Almost all these planets are in the Milky Way. The Kepler mission discovered about 18000 candidate stars of extraterrestrial planets by transit method, of which 262 may exist in the habitable zone of stars. It is believed that after a period of confirmation, the number of exoplanets will increase greatly.

Photo: Kepler telescope, whose main task is to discover and study exoplanets.

When the exoplanet passes through the joint between the earth and the star, it will block the light of some stars, resulting in the decrease of the apparent magnitude of the star by 0.438+0%. This method has high sensitivity, and smaller planets with the mass of 1/30 ~ 1/600 observed by other methods (radial velocity method, etc.) can be found. These planets are about the size of the earth.

The radius of the exoplanet (how much light is blocked) can be roughly estimated by the transit method. Combined with radial velocity method, the mass and orbital parameters of exoplanets can be estimated.

When the planet revolves around the star, it will cause the star to move regularly in a certain range. This motion will lead to the red shift or blue shift of the star spectrum. It's like when the train approaches, the sound of the whistle will become sharper (the wavelength of the sound will become shorter), and when it is far away from us, the sound of the whistle will become lower (the wavelength will become larger). This is the Kepler effect.

Kepler effect can even be used to detect the speed change of 1 m/s, so that the approximate mass of the planet can be calculated.

By analyzing the spectrum of the planet, we can also know the chemical elements in the atmosphere of the planet.

Kepler 452b is one of the planets that are very similar to the Earth discovered by Kepler telescope using transit phenomenon.

Kepler 452b orbits Kepler 452. As can be seen from this name, it is the first planet found in this star (numbered from B). Kepler 452 is a sun-like star, with a mass of 1.04 times that of the sun, a radius of1./kloc-0 times that of the sun, and an age of about 6 billion years, which is1.500 million years older than the sun. This makes its luminosity 1.2 times that of the sun (the older and heavier the star, the stronger its luminosity, and the luminosity of the sun will increase by about 1 0% every1100 million years).

Kepler 452b is about 65,438+0,400 light years away from the Earth. It will take 25.8 million years to get there at the speed of the fastest detector "New Vision".

Figure: Comparison between Kepler 452b (right) and the Earth (left).

According to observation, Kepler 452b is 60% larger in diameter than the earth, 5 times larger in volume and 2 times larger in surface gravity. The distance from the star is about 1.05 astronomical unit (the earth is 1 astronomical unit). One revolution takes 385 days. It is located in the habitable zone of the star. There may be liquid water, which means it may have life. Measured by the Earth similarity index, it is the sixth most Earth-like planet.

However, it is too far away from the earth, and when we have the technology to sail there, it may no longer be suitable for human habitation: Kepler 452 star is dying, and its luminosity will continue to increase, which will make the whole planet dry up and no longer suitable for human habitation. The same is true of the earth, and it will suffer the same fate in about 1 100 million years.

First of all, it is certain that this planet does exist, and many of its indicators are very close to the earth. (Cheerful) All this is due to kepler mission.

Scientists call the star system of this planet Kepler 452 system. Kepler 452b is the only observable planet in this planetary system. Its volume is relatively large, about 4~5 times that of the earth. The gravity above is about twice that of the earth. It is preliminarily concluded that it is an out-and-out rock mass similar to the earth structure. The stars around it, on the whole, are about the same size as the sun and may be bigger than the sun. The brightness will also be brighter. (about 15%~20%. It seems that we are rejoicing here. Maybe we just flew by in a spaceship. Sorry, I have to remind you that the distance between our sun and the stars of Kepler 452 system is about 1400 light years. That is to say, it takes 1400 years to take a light-speed spaceship. This time is enough for human civilization to continue to evolve 1/3. So let me see, it's good to have an eye addiction. )

We have found many planets like Kepler 452b. I remember a long time ago through the Hubble telescope, followed by the Kepler mission. So far, we think that there are probably less than 300 livable planets with "life".

So far, the standard of livable planet we are looking for is almost looking for the twin brother of the earth. The first thing is to have air, plenty of water and proper pressure and gravity. In this way, we searched a large circle of selected ones, which may all be substitutes for the earth! In other words, we are all looking for the so-called "livable planet" according to the living conditions of carbon-based life. But it is no wonder that we have never stepped out of the solar system, or even conducted a thorough investigation of the interior of the solar system. Other forms of life and their living environment are completely unknown to us. We can neither prove that human beings are the only life form in the universe nor prove that carbon-based life forms are the only life forms in the universe.

Therefore, all space exploration activities can be regarded as broadening human horizons and making up for knowledge learning. ...

Let me draw a conclusion first. At present, scientists have not determined which planet in the universe is suitable for human migration, including this kepler-452b.

First of all, we can analyze from the name that this planet was discovered by the astronomical telescope Kepler, and then add a number-452b, indicating that this planet is one of many planets discovered.

Kepler telescope is an optical telescope put into space. According to the current scientific and technological strength of mankind, its observation accuracy is remarkable. It is said that it can make everyone easily see the brightness of a match on the moon.

But what we want to observe this time is a planet similar to Earth -452b, not a star, and the planet will not shine. Kepler is very good, but absolutely no cow can look directly at planets outside our solar system. We observe "kepler-452b" through the transit phenomenon.

Simply put, "transit phenomenon" means that the planet revolves around the star, and when it bypasses the front, it will block part of the light of the star. Theoretically, when we observe a star, it will be darker. Then we can calculate the orbital radius of the planet according to the period of light change and the size of the planet according to the intensity of light change.

At present, Kepler telescope can observe such subtle light changes! Unfortunately, this is all the information, other parameters and possibilities? Let's guess.

If we want to shoot directly, it is not impossible. In principle, it is only necessary to make one pixel in the telescope photo correspond to its resolution. I omitted the calculation process because it was too long. Let's just say that we need a telescope one million times larger than the current Kepler telescope. We can directly regard this planet as an image of 1 pixel.

In short, in order to display only one pixel, the Kepler telescope must be upgraded to the size of 1000 km.

Ok, I have said so much before, so don't ask me this question. Look at the shadow and think about heaven, okay? There is no such thing as a good thing.

Meet on a blind date, at least describe the appearance and physical characteristics. You can't even give a pixel photo, so it's a shadow. You ask me, is this chick beautiful?

So, no scientist will tell you that this can be moved. In terms of the degree of migration, it is not ranked, and Mars ranks first.

There is only one earth, so cherish it. Don't always think about running away, there is no way out at present.

I'm Mr. Cat. Thanks for reading.

From July 2065438 to July 2005, Kepler discovered a G-shaped main sequence star in the direction of Cygnus, which is 1400 light years away. Its brightness is 20% higher than that of the sun, and its mass is 4% higher than that of the 6 billion-year-old sun.

It is not uncommon to look at the surface data of this star alone, but astronomers unexpectedly found that this star has a planet in the livable zone, which is what we call Kepler 452b.

Although this planet was originally touted as a "super earth", according to the Earth similarity index, Kepler 452b is only the sixth exoplanet most similar to the Earth. At present, Kepler 438b is the first one, and another KOI-4878 438+0 with similarity of 0.98 has not been officially confirmed.

Kepler 452 itself is just a star, which is not suitable for human habitation. It is really possible to live on its planet Kepler 452b. Don't confuse these two celestial bodies. With the current technical level, it will take 25.8 million years to reach Kepler 452b, so Kepler 452b will only be a symbol for a long time.

Neither Hubble nor Kepler missions can see the details of planets and stars, and only passive methods such as spectral analysis can determine their mass and possible atmosphere, so Kepler 452b may not be suitable for human habitation. After all, its home planet Kepler 452 is 1.2 times brighter than the sun, which means that there may be vegetation on Kepler 452b.

The brightness of our sun will also increase with time. Hundreds of millions of years later, the earth's oceans will be evaporated by the sun, and the livable zone of the solar system will also move to the orbit of Mars or even Jupiter because of the increase in brightness.

It is irresponsible to declare that a planet is suitable for human habitation under the limitation of current observation methods. The observation that spans thousands of light years itself has low accuracy, and it only sees the state of the target thousands of years ago rather than the real-time state.

Compared with exoplanets thousands of light-years away, there are many new worlds in our solar system that can be transformed, from the moon and Mars close at hand to the moons of Jupiter and Saturn farther away. Most of these rocky planets in our solar system have water resources and atmosphere, which are ideal targets for human colonization and development in the future.

July 20 15, NASA confirmed that Kepler's mission discovered an earth-like planet near this star, namely Kepler 452b. This planet is located in the livable zone of the system, and it is the only confirmed planet in Kepler 452 system.

The orbit of this new planet is 385 days, and it may be a rock body, slightly larger than the earth, with a radius of 1.63 times that of the earth and a surface gravity of twice that of the earth. The G2 star in orbit is 1400 light-years away from the Earth.

This planet and its star are the same as the earth and the sun, but its star is about 20% bigger and brighter than the sun, and its age is over 65.438+0.5 billion years. Although kepler-452b452b is the closest analogue to our Earth-solar system discovered by Kepler, its evolution may continue. It is the same as the future outcome of our planet, because the sun's fuel runs out, expands and evolves into a red giant.

Conclusion: So we should not pin our hopes on this planet, because its star is over 65.438+0.5 billion years old and is not allowed to be the same age as the sun. If so, when the sun becomes a red giant, our earth will not exist, and Kepler 452 will not exist!

How do scientists determine that Kepler 452b is livable?

As of May last year, more than 3,767 exoplanets have been discovered, of which 262 may be located in the habitable zone of stars. Of course, as TESS enters the state, there will be more and more exoplanets and planets in the livable zone in the future! But we only care about one problem. Are all these planets in the livable zone livable? So far away, is there any way to prove that these planets are livable?

The planets discovered by Kepler telescope are compared with the size of the earth. Blue is the size of the earth, green is the super earth, orange is Neptune, and red is the giant gas planet!

1. How did Kepler discover planets?

Except for celestial bodies in the solar system, exoplanets can't be found directly, even the nearest proxima centauri can't be found. We can only find planets by direct transit or indirect Doppler frequency shift!

1, transit method is very simple, when the planet passes between the star and the earth, it will block the star, then there will be a trough on the CCD of the telescope, and the luminous flux will decrease in the future, which is an important basis for detecting the Ling Xing of the planet! But there is a problem, because the conditions in Ling Xing are very bad. Ling Xing can only be observed when the earth is on the ecliptic plane of another galaxy, and only once a week! Therefore, whether it is Kepler or TESS telescope, the only thing to do is to keep taking pictures and taking pictures. ...

The discovery of stars with light changes by TESS telescope is only a preliminary screening. If we want to confirm it, we need to observe it repeatedly until Ling Xing is confirmed. This is a tedious job. Fortunately, Kepler and Tess will not complain!

2. Doppler method is based on the change of wavelength when the planet approaches and leaves the star. This method can detect whether there are planets in the stars that are not on the ecliptic plane of the earth! But the efficiency of this method is worse than transit method, because the planet is too small and the wavelength changes very little, and it takes a long time to observe a certain area to get effective information!

It should be reminded that up to now, 77% of exoplanets have been discovered by transit method!

Second, how to measure whether the planet is livable?

In fact, it must be explained that whether the planet is located in the livable zone can be calculated, and the formula is as follows:

Livable zone (astronomical unit) L=√ Target celestial luminosity/solar luminosity

As long as we know the luminosity of another star, we can calculate the approximate range of its livable zone, but whether the planet in the livable zone is livable is another matter!

So what parameters does Kepler 452b have to support that it is a livable planet?

1, Kepler 452 is a star with G spectrum, similar to the sun, and its mass is about 1.037 times that of the sun!

2. Orbital radius of Kepler 452b: 1.046 astronomical unit.

Period of revolution: 385 days.

4. Planet diameter: 65438+ 0.59 times of the earth.

These parameters are simply replicas of the earth's revolution around the sun, but the size is somewhat different from that of the earth!

All the above parameters can be calculated by Lingxing method with high accuracy! Does this mean that Kepler 452b is a livable planet? Of course, before we come to this conclusion, there have been arguments such as super earth! And this exoplanet 1400 light-years away has a very high voice! It is indeed the most earth-like planet discovered in recent years!

But there may still be results. Everyone knows that both Mars and the Earth are located in the livable zone of the solar system, but the conditions of Mars and the Earth are also known. Mars obviously does not have the ability to survive, at least its natural conditions are not suitable for survival. Compared with Mars, the livable earth is definitely a paradise! If Kepler 452b is as civilized as us, then they can also observe the Ling Xing of the Earth and Mars and calculate that both planets are located in the livable zone, but they can't know that the Earth is more livable!

3. Is there any way to verify that there is liquid water on Kepler 452b?

Now we can know the following data from the obtained parameters:

Therefore, it can only be judged that Kepler 452b is only a possible condition for liquid water, but there is not necessarily water! In other words, all the conditions assumed now, such as super earth or second earth, are compliments from NASA, and the real conditions are really only known by the old genius!

There is a sun, which is close to the earth and our sun. This is the most important judgment. There is Kepler, a planet with the same life as the earth, and the others are unknown for the time being.

Because you can't go, you can't argue.

Have scientists ever said that a mirage is livable?

Guess, everything about the universe is speculation!