Experts estimate that there are anywhere between one and ten trillion planets in the universe. To date, we have confirmed the existence of 5,069 exoplanets. Now, scientists have come up with a new method that could help us find even more.
The Universe is a pretty big place. In fact, it is so large that we have yet to come up with a telescope that can see back in time to the point where it all began. Depending on which expert you ask, there are between 100 and 200 billion galaxies in the Universe. We estimate there are one to ten trillion orbiting planets in the Universe, based on approximately 400 billion stars in the Milky Way. Since the first exoplanet was found, we have come a long way in exploring the galaxy. 1988 was the year when the first exoplanet was suspected of having been detected by science. After a relatively short time, several terrestrial-mass planets orbiting the pulsar PSR B1257+12 were discovered in 1992, which confirmed the detection. Recent years have seen the discovery of thousands of exoplanets.
Confirmed worlds
As of writing, and based on NASA numbers, there are 5,069 confirmed alien worlds, with 8,833 awaiting confirmation. In most cases, these worlds are discovered using the transit method, where an optical telescope measures the brightness of a star over time. There may have been a planet that has passed in front of the star, blocking some of its light if the star dips very slightly in brightness. In spite of its power, the transit method has some limitations. A planet cannot be detected unless it passes between us and its star. An optical telescope is also required for the transit method. Radio telescopes, however, could help astronomers detect exoplanets as well.
Difficult observation
At radio wavelengths, observing exoplanets is difficult. Planets emit relatively little radio light, while stars emit more. A stellar flare, for instance, can also cause the radio light from stars to vary quite a bit. Some large gas planets, however, are radio-bright, such as Jupiter. This is due to the planet’s strong magnetic field, not to the planet itself. The magnetic field reacts with charged particles in the stellar wind, generating radio light as a result. Radio signals from several brown dwarfs have been detected with radio telescopes, and Jupiter is so bright in radio light that it can be detected with a homemade radio telescope. Astronomers have reported no clear radio signals from Jupiter-like planets orbiting other stars.
Magnetohydrodynamics
This study examined the possible characteristics of such a signal. An expert team used magnetohydrodynamics (MHD), a theory that explains the interaction between magnetic fields and ionic gases, to construct a model of the Jupiter-sized world of HD 189733. Simulations were performed to determine the planet’s radio signal based on the interaction between the star’s stellar wind and its magnetic field. As a result of this study, the team found that the planet would produce a clear light curve. Depending on the movement of the planet, that radio signal varies. The radio provides extremely accurate measurements of motion, which is great.
Specific characteristics
Additionally, they found that radio observations were capable of detecting planets transiting in front of their stars. The radio signal shows specific characteristics when a planet’s magnetosphere passes in front of a star. The magnetosphere could be measured to understand its strength and size better. The only problem is that most of these signals would be very faint, requiring a new generation of radio telescopes to be built to detect them. However, detecting these planetary radio signals would allow us to measure the orbits of the planets in the system and would help us learn more about their composition and interiors.
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