The number of extrasolar planets Confirmed reached 6000 altitude, from small rocky planets to the gaseous giants passing through the worlds more similar to the earth. Nasa announced the finish line, which monitors the number of exoplanets – that is planets outside our solar system, in orbit around other stars – through the Exoplanet Science Institute. In addition to the confirmed planets, always according to the American space agency, there are more than 8,000 exoplanet candidates Waiting to be officially recognized. But what does this result really means? How were these planets discovered? And what does the future of research on exoplanets reserve for us?
How the exoplanets are discovered
Most of the extrasolar planets are detected indirectly. The main methods are that of transit and that of radial speeds. The transit method is conceptually simple: observing how the passage of a planet in front of its star (transit) compared to our line of view regularly decreases the brightness of the star itself.
The radial speed method instead uses particular spectroscopic techniques to observe the movement of a star along our line of view, caused by the gravitational disturbances exercised by a sufficiently massive planet and close to the star.
Then there is the method ofimaging directin which the planet is directly observed as a very powerful telescopes image, such as the James Webb Space Telescope. There are very few planets discovered in this way.
The difficulty in discovering new extrasolar planets lies in the fact that the planets are incredibly weak compared to the stars around which they orbit. For this, even if today we can confirm the existence of over 6000 extrasolar worlds, we know that the real number of existing planets is much higher.
The variety of extrasolar planets confirmed by NASA
The rapid growth of extrasolar planets allows us among other things to better understand how the populations of planets are distributed in the Milky Way. For example, it seems that The rocky planets are much more common compared to what we observe in the sun system.
The scientists also discovered a wide range of planets completely different from those of our galactic isolated. There are large planets like Jupiter but who orbit around their most closest to how much mercury does with the sun. There are then the so -called Lava worldsrocky planets so hot that their crust is completely melted. Still others orbit around two stars, or do not orbit at all, wandering the cosmos like wandering planets. There are planets with a density similar to that of polystyrene, and even those with clouds made of gems.
Know this variety helps us to understand how planets are formed And what are the conditions in which they can develop. Helps us understand how common the planets similar to the earth areand where we should look for them.
The search for new worlds and future missions
In fact, what excites us most is the possibility of discovering worlds similar to the earth potentially habitable. For this reason, the exoplanets that are found in the habitable of their star, that is, that region in which temperatures are such as to allow the presence of liquid water on the surface of the planets themselves. These worlds, provided they are rocky and not too different from the earth in terms of mass and size, are considered potentially habitablethat is, in principle of degree to offer the right conditions to host life as we know it.
The progress in this field are rapid and exciting. The James Webb spatial telescope, for example, is able to analyze the chemical composition of the exoplanetary atmospheres, allowing in particular to identify so -called bioferme (Biosignatures in English), that is, chemicals that represent clues to a possible presence of life.
For the search for new exoplanets, NASA has the Nancy Roman spatial telescope in the pipeline, equipped with an innovative coronographer Able to block the light of a star to directly identify the planets that orbit them around. The American space agency also scheduled a future tool called Habitable Worlds Observatory designed specifically to discover planets similar to the earth and potentially able to host life.
