Have you ever wondered how many planets there are in the universe? It is difficult to determine the exact number of exoplanets (those orbiting stars other than the Sun), but astronomers estimate that there are billions of worlds in the universe, far from our neighbors on this planet. Solar System🇧🇷
Until a few decades ago, the solar system’s planets were the only ones known, and it wasn’t until the early 1990s that a team of astronomers discovered the first exoplanet. In 1992, Aleksander Volszkan and Del Friel were studying pulsate PSR B1257+12 which, from time to time, stops emitting its light pulses.
As they study the object, they conclude that the pulsar has two planets that orbit it every 67 and 98 days, respectively. This was the first time that the existence of planets around a star other than our own was confirmed. Today, there are more than 5,000 confirmed exoplanets Just in our galaxy, the number of new planets discovered is constantly increasing.
After all, how many planets are there in the universe?
As we have explained, astronomers have not determined an exact number of exoplanets in the universe, and some studies indicate that there are between 100 and 200 billion planets in the universe alone. Milky Waybut this number should not be seen as an estimate of the total number of such worlds, but the minimum possible number of such worlds.
If we factor in calculations that take into account exoplanets such as those in the solar system, we would come to a total of ten trillion planets in the Milky Way – and this is without considering the “orphan” planets, that is, those in space without orbiting stars. By including them, the number can reach 10 planets.
So far, we’re talking about trillions of possible planets in the Milky Way alone. As we already know there are at least 200 billion more galaxies In the universe, then, we can estimate that there are 10²⁵ exoplanets orbiting stars — or, if you prefer, 100,000,000,000,000,000,000,000 worlds in the visible universe.
How do scientists find planets outside the solar system?
Most exoplanets are found through the so-called “transit method”, which telescopes like Transiting Exoplanet Survey Satellite (TESS) Watching stars for small dips in brightness due to the passage of planets in front of them. Using the star’s light curve, scientists can determine the inclination of the orbiting planet and its size. In 1999, researchers observed the first planet to use this method.
Others found byradial velocity method🇧🇷 This technique is also known as the “wiggle method”, and it works with the gravitational system that is made up of the planet and its star. If it has a lot of mass relative to the star, then spinning around it can cause a small wobble in the center of mass around it.
This tiny fluctuation can be identified by shifts in the frequency of the star’s light: if the star were moving toward the observer, its light spectrum would shift slightly bluer. If it is moving away, the skew will be towards the red. Thus, by identifying periodic changes in the star’s light spectrum, astronomers may suspect a large planet orbiting the star.
