How does NASA find exoplanets? The explanation is here

Credit: NASA/JPL-Caltech/R. Hurt (IPAC)
Credit: NASA/JPL-Caltech/R. Hurt (IPAC)

How does NASA find exoplanets? This is a very big question that you will definitely want to answer. You've probably thought that exoplanets can be seen through telescopes on Earth, but that's not the case, it's almost impossible to see an exoplanet with a telescope on Earth, even if the exoplanet is very large. So far, NASA has discovered 4,903 confirmed exoplanets. There may be trillions of such exoplanets in our galaxy, but they are extremely hard to find. 

It is not so easy to find an exoplanet even if you use the Hubble telescope. First of all, the exoplanets do not shine like the stars they orbit. They shine billions of times fainter than the stars they orbit. Their brightness is so faint because the planets do not produce light, and the only light that reaches them is from the star they are orbiting. The only planets that have a little brightness are the newly formed planets, the ones that have just been born. Those have a small shine, but not very long-lasting. 

Another problem with finding exoplanets is that they are a huge distance from us. Some exoplanets are impossible for Hubble to see. The Hubble Telescope can see up to a magnitude of 28-29 and a maximum could be a magnitude of 30. We see the sun so well in the sky because it has a magnitude of -26.74. Think about how far Hubble can see, at 28-29. And yet some exoplanets are so far away that they cannot be seen at all. Because it is best to look at the magnitude of a star, most exoplanets are found after the stars they orbit have been found.

The problem is that there are situations when exoplanets are lost in the brightness of parent stars. When this happens, only the star can be seen without seeing any exoplanets. But when there are situations like this, astronomers research and try to observe the place where the star was found as well as possible, so that in the end they can find evidence of the existence of exoplanets. 

The size of the exoplanets and their masses (most of them) are much smaller than that of the orbiting star. However, even though the size of the exoplanets is much smaller and far away, astronomers have had extremely rare cases when they could see an exoplanet from Earth with telescopes. How? First of all, the exoplanets seen on Earth were young gas giants. That is, they were newborn planets (they had a certain brightness) and huge dimensions, so astronomers could see them with high-performance telescopes on Earth.

But the methods for finding the above exoplanets are rarely used by NASA. NASA scientists have another, more complicated way to find exoplanets. NASA researchers have suggested that a widely used method of finding exoplanets is the indirect method: "Measuring the dimming of a star that happens to have a planet pass in front of it, or monitoring the spectrum of a star for the tell-tale signs of a planet pulling on its star and causing its light to subtly Doppler shift." With this method, NASA's Kepler space telescope finds thousands of planets. But the telescope can also find exoplanets by other methods such as gravitational lenses, the "ballooning method" and direct imaging.

Article by: Andacs Robert Eugen, on 23 January 2022, at 01:38 am Los Angeles time

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