The sun's movement across the sky is so predictable that it's impossible to believe its relationship to the Earth is changing all the time, but that's a fact. In reality, the average distance between the Earth and the Sun is not constant, as it changes from year to year. So we know that the Earth is slowly moving away from the Sun. In this sense, is it necessary to worry? What are the impacts of this? Check out all this information in the content below!
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Earth's slow moving away from the Sun
The truth is that, over time, the Sun is slowly moving away from Earth. However, its orbit is somewhat oval rather than perfectly round. Therefore, according to NASA (National Aeronautics and Space Administration), the distance between the stars can vary from approximately 147.1 million to 152.1 million kilometers.
Still, on average, the distance between the Sun and Earth is increasing very slowly over time. This distance that has been occurring has two significant causes:
- The first is that the sun is losing its mass;
- The second cause concerns the same forces that cause tides on Earth.
The sun is losing mass
Just as the Sun is always generating energy, mass is also being lost. Some models, which dictate how stars change over time, predict that during the course of the planet's lifetime, Sun, estimated to be 5 billion years old, it will lose about 0.1% of its total mass before it starts to to die.
While 0.1% may not seem like a lot, according to scientists, it is a significant amount when referring to the big star. To give you an idea, this amount would be approximately equal to the mass of Jupiter (which is about 318 times the mass of Earth). The strength of an object's gravitational attraction is proportional to the amount of mass it has. As the Sun loses mass, its attraction for Earth weakens, causing our planet to move away from the star by about 6cm each year. But we don't need to worry about anything right now.
The forces that cause the tides on the planet
Similar to the way the moon's gravitational pull causes seas to form on Earth, the planet's gravity also pulls on the sun. The result is a "tidal bulge," according to Britt Scharringhausen, professor of physics and astronomy at Beloit College. However, these tidal forces have a very weak impact on the entire Earth's orbit. Because of them, the Earth moves away from the Sun by only about 0.0001 inches (0.0003 cm) each year.
