How exoplanets are discovered is the most important question of this decade. In this modern era, when scientists are exploring new worlds in space. One biggest question appears in our minds: how do they do such things or what technology do they use?
A few decades ago, we didn’t even know about the existence of any exoplanets beyond our solar system. But now scientists from NASA and other space agencies confirmed nearly 6000 exoplanets in space by using advanced technology and innovative detection methods.
In this article we’re going to discuss the technology used by scientists and how exoplanets are discovered.
How Are Exoplanets Discovered by Scientists?
First of all, we have to understand that exoplanets are very difficult to see directly. Like our earth has its star, the sun, these exoplanets also have their own host star, and they are hidden under the bright light of their star. Because of this bright light, scientists do not see them directly, so they have to rely on the indirect methods to detect them.
Here are some innovative methods of modern technology used by scientists to discover exoplanets beyond our solar system.
Transit Method:
The transit method is the most successful and widely used method by scientists today. This method works by observing the brightness of the star over a long time. When the planets pass in front of the star, it blocks some light and creates a black spot. By observing this many times, scientists can confirm it as a planet. Now scientists can even calculate its size, orbit, and the distance from its host star. Missions like the Kepler space telescope and TESS made this transit method very successful. These missions can monitor thousands of stars in space at once and detect even a small change in their brightness. The transit method helps scientists to discover thousands of exoplanets. The transit method is one of the best methods to discover exoplanets beyond our solar system.
Radial Velocity Method:
It is another modern technical technique used by scientists to discover exoplanets in space. This method describes how exoplanets are discovered. This method observes the star of the planet and how it is influenced by the gravity of its orbiting planet. When a planet revolves around the star, its gravitational force impacts the star a little bit. As a result, a star makes a very small forward and backward motion, which is called a wobble.
This motion is extremely tiny; it cannot be seen directly. But scientists can detect it by observing its brightness using the Doppler Effect. When the star moves towards earth, its light changes slightly into blue, and when it moves away from the earth, its light changes slightly into red. Very sensitive instruments called spectrographs are used by scientists to observe these tiny effects. Scientists observe these changes for a long time, and if brightness shifts repeat regularly, then it is confirmed that a planet is revolving around that star.
This method is widely used by NASA and other space agencies to detect exoplanets. This method is more effective for large planets. With the help of this method scientists can even calculate the orbital period and the shape of the orbit.
Direct Imaging:
This is another method of describing how exoplanets are discovered. It is one of the most difficult methods to detect any planets in space. In this method scientists capture real planet images instead of using any indirect signals. This method is most challenging because the star is much brighter than its planet. So when we capture an image, starlight hides the planet. But scientists use an instrument called a coronagraph to get rid of this problem. This instrument blocks the starlight, and then we can take the planet’s picture. This method gives us real images of exoplanets, and it is more useful for large planets. Advanced space telescopes like the James Webb Space Telescope are used in this method to detect planets beyond our solar system.
Gravitational Microlensing:
In this method, scientists observe the effect of gravity on light to detect exoplanets. This method depends on the general relativity theory. This theory states that any massive object in space like stars can bend light due to its gravity. This method is very effective for discovering new planets. This method can detect very distant planets and the planets that are orbiting far from their host stars. It can also detect Earth-sized planets beyond our solar system. NASA and other space agencies use this method to detect many exoplanets in space. It is another innovative method that describes how exoplanets are discovered.
Astrometry:
This method gives the exact position of a star in the sky. This method focuses on the positional movement of a star in the sky to detect exoplanets in space. When a planet is orbiting around a star, the gravitational force of the planet make star move. But star makes an extremely tiny motion called a wobble. As I told you before, in the radial velocity method, scientists observe a star coming towards earth or moving away from earth. But the astrometry method observes stars’ side-to-side motion (left-right motion). To detect any exoplanet, scientists observe star movement constantly for a long period. If a star’s movement shows a regular pattern, then it confirms that any planet is revolving around it. This method can detect the mass, shape, and size of the planet. It can also detect the exact direction of its motion. This method helps scientists to detect new worlds beyond our solar system, and it describes properly how exoplanets are discovered.
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Some Famous Exoplanets
Kepler-452b
Kepler-452b is one of the most Earth-like exoplanets ever found. It orbits the star named Kepler-452. The star Kepler-452 is about 1400 light-years away from the earth. This exoplanet was discovered in 2015 by using the Kepler Space Telescope. It takes about 385 days to complete one orbit around its star. Its star is a G2 type, which is very similar to the sun. Its radius is about 1.6 times the radius of the earth.
Kepler-452b was discovered by using the transit method. The Kepler Space Telescope made this discovery possible. It is able to detect thousands of space objects at a time.
Proxima Centauri b
Proxima Centauri b is an exoplanet that orbits the red dwarf star called Proxima Centauri. It was discovered in 2016. Proxima Centauri is the closest star to our sun at the distance of about 4.24 light years. This star is a part of the Alpha Centauri triple system. The planet’s minimum mass is about 1.27 times the Earth’s minimum mass. It takes about 11.2 earth days to complete its one orbit around its star.
The exoplanet Proxima Centauri b was discovered by using the radial velocity method. This method observes the wobble of the star caused by its orbiting planet’s gravity.
TRAPPIST-1e
TRAPPIST-1e is another earth-sized exoplanet. It orbits an ultra-cool red dwarf star named TRAPPIST-1. It is about 40 light years away from us. The TRAPPIST-1 star system consists of 7 planets, and TRAPPIST-1e is one of them. It was discovered in 2017 by NASA’s Spitzer Space Telescope. It takes about 6.1 earth days to complete one orbit around its star. Its mass is about 0.77 times the mass of the earth, and its radius is about 0.91 times the earth’s radius.
TRAPPIST-1e was discovered by using the transit method. The transit method is most widely used to detect exoplanets, and it also helps to calculate their size and orbit. Scientists have already discovered thousands of exoplanets by using the transit method.
HR 8799 planets
The HR 8799 planets are orbiting around a young star named HR 8799. This star is about 129 light years away from our sun. In the set of HR 8799 planets, planets b, c, and d were discovered in 2008, and later planet e was discovered in 2010. These planets are massive, and they orbit far from their star.
These exoplanets were discovered by using the direct imaging method. This method helps to describe how exoplanets are discovered.
OGLE-2005-BLG-390Lb
OGLE-2005-BLG-390Lb is a distant exoplanet. It is orbiting a distant red dwarf star. It was discovered in 2006. Its mass is about 5.5 times the earth’s mass. Its distance is about 21000 light years.
The gravitational microlensing method is used by scientists to discover this exoplanet. This advanced method is very useful for detecting extremely far planets, and it describes very well how exoplanets are discovered.
Conclusion
In this article I explain some modern innovative methods used by scientists today to detect exoplanets beyond our solar system. These methods explain properly how exoplanets are discovered. Scientists are continuously working on technology and improving their methods to find new worlds in deep space and to uncover the hidden mysteries of the cosmos. As technology evolves, scientists grow their thinking. They are trying to find any planet that contains life or has suitable conditions for life. Now in the modern era, the possibility of finding an Earth-like planet becomes more real than ever. I hope you can understand how exoplanets are discovered.