Scientists so want to find extraterrestrial life or discover new planets, that in connection with these goals, many ways have been invented to find exoplanets, which I will talk about in this article.
Initially, it may seem that all that is needed to discover a new celestial body is an excellent powerful telescope and good perseverance along with patience, but this is not entirely true, because it is quite difficult to find alien and distant worlds. The biggest hindrance is long distances. Another obstacle is the size of the planets, because they are much smaller than stars, even giant planets. And planets that are too close to their home star are difficult to distinguish, because the bright light of these stars prevents them from being seen. At the same time, if the planet is located far enough from the star, then, again, it will be difficult to notice it due to the fact that it reflects light too weakly - such a dim brilliance can only be seen with difficulty in a very powerful telescope. So this method is not the easiest one - only 7% of exoplanets were discovered with it.
In another way, it is also called the Doppler method. Stars are gravitationally bound to their planets. If some massive planet revolves around the star, then the star will not be in a state of absolute rest in one place, but will oscillate. For example, this one can be compared to when an adult takes a child's hands and begins to spin with him. A child is a planet, and a star is an adult. The child is spinning, but the adult will not stand at one point, but will slightly move away in the direction of the child's movement. With this illustrative example, you can imagine an astrometric method, which consists in accurately measuring the position of a star in the sky and determining how this position changes over time. If a planet revolves around a star, then its gravitational effect on the star will cause the star itself to move in a small circular or elliptical orbit. This is how the planet in the constellation Pegasus was discovered - Bellerophon, a gas giant on which it rains from red-hot drops of iron.
Astrometric method well complements the radial velocity method, which is associated with the motion of a star and oscillation around the common center of mass of the planet - in this case, there is a shift in the spectrum of the star. When a star moves away from us, the wavelength of light increases, and the lines of the spectrum are shifted to the red region (red waves are long). As a star approaches us, the spectrum shifts to the blue, shortwave region. The oscillations of the star themselves are quite difficult to notice, especially if the planet is small, but the spectral lines will immediately give it out. And since the spectrum changes, it means that something affects the star. What could it be? Planet! The Doppler method is good only for detecting large planets or for clarifying information about new finds obtained earlier, since small planets will not cause the star to wobble too much.
Perhaps one of the easiest: when a planet passes through the bright disk of a star, you will see it as a small black dot. But this method is successful when the orbit of the planet relative to us is located at such an angle that its passage along the stellar disk will be clearly visible from the Earth. The luminosity of the star during the transit of the planet will become less - by calculating the change in luminosity, one can determine the size and even the physical properties of the planet. Using this method, the Kepler space telescope discovered about 2,300 new planets!
Near neutron stars, we are unlikely to find something alive, but the planet cannot always boil with life, and we know this very well. Neutron stars are superdense rapidly rotating objects with a temperature of 93 million K! In the process of their rapid rotation, they emit intense radiation in the form of rays that are destructive to all living things. When such a beam of light falls on the Earth (no, this is not fatal, because neutron stars are very far away), an observer from Earth can notice a pulsation of energy (therefore, neutron stars are called pulsars). If there is a planet next to such a star, then by its gravity it will cause fluctuations in its light. All a person who wants to discover a new planet needs is to measure the variability of the pulse, which will make it possible to determine the mass of the planet and its orbital characteristics.