by From a very young age, we are taught to understand that the planets of our solar system change as they orbit a central star, the sun. But does the sun itself move within the solar system?
Well, in general the sun is far from static in the universe. We know, for example, that our star orbits the heart of the Milky Way at dizzying speeds of up to 450,000 miles per hour (720,000 kilometers per hour) and drags the entire solar system along with it.
During the day, the sun also appears to be moving away from our vantage point. It crosses across the sky above Earth, giving us beautiful sunrises and sunsets. This movement, however, is a result of the rotation of the Earth; it is not a result of the actual motion of the sun.
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In addition, during an Earth year, known as 365.3 days, the sun’s position in the sky also changes from our perspective. Still, according to Royal Greenwich Museumthat is not the result of the sun actually moving, but the result of the Earth’s tilt, or that our planet has a flattened “elliptical orbit” so it is sometimes closer to the sun with during the year than at other times.
The length of its year is determined by the time it takes for a planet to complete one full orbit of the sun, and the shortest year is that of the planet closest to the sun, Mercury. A Mercury year equals 88 Earth days. The longest planetary orbit in our cosmic neighborhood is that of Neptune, which has a year lasting 60,182 Earth days (164.8 Earth years).
But returning to our main question, the short answer is that the sun does indeed change position within the solar system, albeit very slightly. That limited oscillatory motion or “swallowing” results from the gravitational influences of the planets orbiting the sun.
Patrick Antolin is a solar scientist at Northumbria University who specializes in phenomena we observe in the solar atmosphere, and in particular, in the solar corona, which is the most extended layer of the sun’s atmosphere.
“Movement is always relative to the frame of reference. The solar system orbits around the center of the Milky Way — our galaxy — but even within the frame of the solar system, the sun is not exactly static due to the gravitational interaction with the other. bodies in the system,” Antolin told Space.com.
The solar scientist said that the gravitational interaction between two bodies is a two-way street. As body one pulls on body two, body one is also pulling on itself, even if the size difference between the two bodies is very large, as is the case with the sun and the planets of the solar system.
“Due to the large mass difference between the sun and any other body in the solar system, the sun is the main gravitational attractor and has no major influence on the gravity of any of the other planets,” he added.
The net result of all this is that the planets of the solar system do not technically orbit their star. Instead, the sun and all planets orbit a point of common gravity called “bar center,” which determines the location of the bodies in question.
Because the sun is much more massive than the planets, these barycenters are located deep within the sun; if a planet’s mass is small, the barycent center it orbits falls closer to the sun’s core. And the closer these supposed centers are to the center of the sun, the less the sun will be slipping because of their orbit.
“With a good approximation, the small gravitational pull from any other planet can be neglected,” said Antolin. “However, our instruments and our theory are precise and advanced enough that we can detect the small deviations from these additional gravitational pulls exerted by the other bodies on the sun, and especially those produced by Jupiter, which is more massive than all other suns. system planets together.”
The sun is about 1,000 times more massive than Jupiter, which is the fifth planet in the solar system, so the gas giant’s effect on the sun is no more than a 40-mile-per-second “wobble” times over. 12-Earth year orbit of the planet around its star, according to Lick Observatory.
Stellar wobbles caused by orbiting planets can be detected by the change in wavelength of light they produce, similar to the Doppler shift. This means that the Doppler effect can be used to detect planets orbiting stars outside the solar system, known as extrasolar planets or “exoplanets.” As a star moves, the wavelength of its light is stretched and it becomes redder as its motion is directed away from Earth, known as “redshift.” As a star moves towards Earth, the wavelength of its light is compressed, giving it a rather blue color, known as a predictable “blueshift”.
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This effect can not only be used to detect stellar wobble and thus detect the presence of exoplanets, but it can also be used to measure some of the properties of bodies in distant planetary systems.
“If one can detect the wobble as well as the speeds of the bodies, then one can infer the masses and the distances between each other,” Antolin said. “This can be applied to any star system where we can detect the wobble and measure the speeds of the rotating bodies.
“Of course, there is additional complexity when there are more than two massive bodies involved, but numerical models can often help determine the most likely number of planets involved in the wobble.”
