Various methods used to search for extraterrestrial planets (exoplanets)

- Discovery-Dr. Vihari shadow

- There are mainly three methods used to find planets outside the solar system. 'Wobble effect', 'transit method' and 'microlensing method'

There are eight planets in the universe. There is no life on any of these planets except Earth. If there was life anywhere else in this universe it could only be on the planet. There is no possibility of life on any celestial body or star other than the planet. So across the solar system in search of life elsewhere in the universe, we, first, have to look for a planet. A few years ago today, no planets were discovered beyond the Tsar. However, astronomers hoped that there would be more than one planet beyond the solar system. About 200 years ago today, the Italian philosopher and astronomer Giordano Bruo argued that "there are an infinite number of stars in this universe and an infinite number of planets revolving around them."

But the clergy considered him a hypocrite and crucified him. The famous astronomer Carl Sagan was almost of the same opinion. But other scientists were not ready to believe this. According to Carl Sagan, not a single planet has been discovered outside the solar system. What about billions of planets? But a year before his death, a team of scientists found evidence that there was a planet beyond the solar system, as science knows it supports Kal Sagan. There is a star called '91 Peggy 'about 50 light years (200,000,000,000,000,000,000) away from the Earth. This star seemed to have a gravitational pull. This pull should be due to the planet orbiting it. This planet should be equal to the mass of Jupiter in the solar system. It should be a ball of burning air. The closest planet to our Sun, Mercury, must have been orbiting eight times closer to its own Sun. All these findings were obtained by the scientists through their own research.

The question here is whether the star, which is 20 million kilometers away, looks like a small bright spot even in a telescope. This makes his planet many times smaller. If it cannot even be seen, then how can its existence be known? How can this be found? In short, how will the planets at such a distance be judged?

One after another, extraterrestrial planets (exoplanets) are being discovered outside the solar system. With the discovery of exoplanets, interest in the search for extraterrestrial life has grown. The least known planet is Draugar (also known as PSR B1257 + 12A or PSR B1257 + 12B), which is about twice the mass of the Moon. The largest planet, according to NASA archives, is HR2562B, which has a mass of 50 times that of Jupiter. Most of the planets discovered so far are within the Milky Way. There is evidence that extraterrestrial planets (exoplanets) also exist in galaxies outside the Milky Way.

Astronomers have discovered extremely hot planets, cold planets, planets orbiting yellow stars, planets orbiting red light stars, planets orbiting brown dwarf stars, and two orbiting planets simultaneously. Astronomers have discovered more than 4,000 exoplanets in the last few years.

3 to 4 methods have been adopted to find planets outside the solar system. There are three main methods used. One is called 'Wobble Effect'. The second method is called 'transit method' and the third method which is being used is called 'microlensing method'. It is interesting to know what are the methods for finding a planet and how to find a planet through it.

The wobble effect is due to the reciprocal pulling applied by gravity. What is this wobble effect? That is the question. The reason why a planet revolves around a star is because of the gravitational pull of the star on the planet. The reason the earth revolves around the sun is because of the gravitational pull of the sun on the earth. Just as a star pulls a planet, so a planet pulls a star. But the mass of the planet is less than the mass of the star so that the star is slightly stretched. In most cases it is not noticeable but if the planet orbiting the star is large then the star feels the pull of the planet. That is why the star is 'wobbly', it is called wobble. If you can't see the stars from all these distances, then why do you know?

When the planet revolves around the star and comes in front of us, the star falls towards us. The result is an increase in the frequency of light coming from a star, i.e. the oscillations of light per second, according to a physical phenomenon called the Doppler phenomenon. This increase is called 'blue shift'. When the planet orbits and follows the star, the star moves away from us. The result is a decrease in the frequency of light emanating from it according to the 'Doppler phenomenon'. This is called 'red shift'. If we get the spectrum of light coming from the star at different times, we will see 'blue shift' and 'red shift', we will know whether the star is wobbly or not. Of course the planet cannot be seen but the existence of the planet can be known by knowing the star's wobble. The second method is called the transit method. It is called transition method in Gujarati. We should also know what the transit method is. There are eight planets in the solar system. Among them Mercury and Venus revolve around the Sun between the Earth's orbit and the Sun. Mercury is small and very close to the sun. Venus is also small and far from Earth. When one of these planets passes right between the Sun and the Earth, a small black dot appears to pass over the sun's radiant saucer. This phenomenon is called transit. This is how Mercury and Venus transition.

The transition of Mercury or Venus passing in front of a large radiant saucer of the Sun seems to be moving a black sesame drop. But if a planet passes in front of a sun outside the solar system, i.e. a star itself is like a bright dot, then it transitions, but it cannot be seen directly, of course it can be known indirectly. The observer should note the intensity of the light coming from the star. And find out whether it fluctuates at regular intervals. Telescopes with CCD cameras can record such fluctuations. But even the largest telescopes used in this method cannot detect Earth-sized planets.

Earth-sized planets are likely to have life the size of Earth. The gravitational micro-lensing method is used to find such planets. Astronomers have discovered the smallest and almost Earth-like planet outside the Solar System. It is orbiting a red dwarf 3,000 light years away. It is close to the center of the 'galaxy' by our star faith 4,000 light years away. We know that the galaxy is our star world, the galaxy. Our sun is one of the billions of stars in it. The Earth-like planets that have been discovered so far are orbiting dying neutron stars but the above planet orbits a normal star. It was discovered by French astronomers. This discovery is known to have been caused by a microlensing event. OGLE - 2005-BLG-390Lb The planet is a cold, rocky world. Its surface temperature is below 40 degrees Celsius. There is no possibility of life there as it is extremely cold.

Microlensing is an astronomical effect. It is Albert Einstein's method of relativity. Accordingly, whenever light from a distant star passes by a large massive star, the light bends and amplifies due to gravity. We know that light passing through a lens also bends and forms a reflection. Hence the name microlensing here. Here the light from the star passes through the star in the middle of its path and it continues to bend and magnify for days and weeks. If the star has a planet orbiting it, in addition the light does not bend and magnify for a few hours due to the gravity of that planet. So it gives extra shine. This glow bears witness to the existence of an Earth-like planet.

Scientists at the University of Canterbury have recently discovered a rare new super-Earth planet near the center of the Milky Way galaxy, also known as the Galactic Bulge. It is comparable to Earth in terms of size and orbit. According to Dr. Antonio Herrera Martin, who led the research, the planet was discovered using a technique called microlensing.

Microlensing is the only known method that can detect planets thousands of light years from Earth. Our galaxy extends that far. There are 150 million stars in the center of the Milky Way. These stars are detected by the Optical Gravitational Lens Experiment (OGLE) method, which contains 3% red dwarf stars. It has small stars. Their mass is between 10% and 30% of our Sun. So objects move around it slowly. It takes a long time for them to collide and connect and grow. They can't get too big. So it is more likely to be like Earth. Somewhere out of all these red dwarfs there will be a planet that has the potential to evolve and evolve like Earth. Thus microlensing is the only method that can examine the planets in the galaxy.

In addition, it is virtually impossible to find any host orbiting without stars, roughly Earth-sized, using 'free-floating planets' (FFPs), using traditional exoplanet detection techniques - seemingly detectable by the effect of microlensing.