From an early age, we are taught to understand that the planets in our solar system change positions as they orbit a central star, the Sun. But does the Sun itself move within the solar system?
In general, the sun is far from static in the universe. For example, we know that our star is orbiting the heart of the Milky Way at an astonishing speed of up to 450,000 miles per hour (720,000 kilometers per hour), dragging the entire solar system with it.
The sun certainly appears to be moving throughout the day from our vantage point as well. It passes through the sky above Earth, giving us beautiful sunrises and sunsets. However, this motion is a result of the Earth’s rotation; It is not the result of the actual movement of the sun.
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Additionally, throughout a familiar Earth year of 365.3 days, the sun’s position in the sky changes from our perspective as well. still see Royal Museums GreenwichThis is not due to the sun actually moving, but because of the tilt of the Earth, or the fact that our planet has a flattened or “elliptical orbit” and is therefore sometimes closer to the sun during a year than at other times.
The time it takes for a planet to complete a complete orbit of the Sun determines the length of the year; The shortest year is that of Mercury, the planet closest to the sun. Mercury’s year is equal to 88 Earth days. The longest planetary orbit in our cosmic neighborhood belongs to Neptune, one year of which lasts 60,182 Earth days (164.8 Earth years).
But back to our original question, the short answer is that the Sun does indeed shift position within the solar system, even if only by a small amount. This limited oscillatory motion, or “wobble,” is due to the gravitational effects of the planets orbiting the Sun.
Patrick Antolin is a solar scientist at Northumbria University who specializes in the phenomena we observe in the sun’s atmosphere, and in particular the solar corona, the largest layer of the sun’s atmosphere.
“Motion is always relative to the reference frame. The solar system rotates around the center of the Milky Way (our galaxy), but even within the solar system frame the sun is not completely static due to its gravitational interaction with other solar systems. “The bodies in the system,” Antolin told Space.com. a.
The gravitational interaction between two objects is a two-way street, the solar scientist said. While the first object attracts the second, the first object is pulled back upon itself, even if the size difference between the two objects is very large, as is the case with the sun and the planets in the solar system.
“Because the mass difference between the sun and any object in the solar system is large, the sun is the main gravitational attractor and is not affected much by the gravity of other planets,” he continued.
The net result of all this is that the planets in the solar system do not technically orbit their stars. Instead, the Sun and each planet revolve around a point of mutual attraction called “”.center of gravityits position is determined by the masses of the objects in question.
Because the sun is much larger than the planets, these centers of gravity are located deep within the sun; If a planet has a small mass, its center of gravity is closer to the heart of the sun. And the closer these centers of gravity are to the center of the sun, the less the sun will wobble as it orbits it.
“With a good approximation, the small gravitational force from any other planet can be neglected,” Antolin said. “However, our instruments and theory are sensitive and advanced enough to be able to detect small deviations from these additional gravitational pulls exerted on the Sun by other bodies, and in particular those produced by Jupiter, which is larger than all other solar stars in the system planets combined.”
The Sun is about 1000 times larger than Jupiter, the fifth planet in the solar system, so the gas giant’s impact on the Sun is no more than a “wobble” of 640 km per hour. The planet’s orbit around its star for 12 Earth years Licking Observatory.
Stellar wobbles caused by orbiting planets can be detected by the change in wavelength of the 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, called extrasolar planets or “exoplanets.” As a star wobbles, the wavelength of its light is stretched and becomes redder as its motion is directed away from Earth; this is called “redshift”. As a star moves toward Earth, the wavelength of its light is compressed and its color becomes relatively bluer; This is called “blue shift”.
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This effect can not only be used to detect a stellar wobble and thus detect the presence of an exoplanet, but also to measure some properties of objects in distant planetary systems.
“If the wobble of objects as well as their speed can be determined, then one can have an idea about the masses and the distances between each other,” Antolin said. “This can be applied to any star system where we can detect wobble and measure the velocities of rotating objects.
“Of course, additional complexity arises when more than two massive bodies are involved, but numerical models can often help find the most likely number of planets involved in the wobble.”