The average distance between Sun and the Earth is getting bigger with the passage of time. What are the reasons for this situation? Should we worry?
According to POT, the distance between the Sun and the Earth is 150 million kilometers, but the orbit of the star is not perfectly circular, but slightly elliptical or oval. It can range, therefore, between 147.1 million and 152.1 million kilometers.
Currently, the star king would be moving away from our planet. There are two specific reasons, according to the scientists cited by Livescience, in a note written by Charles Q. Choi:
- The Sun is losing mass.
- The forces that cause the tides on Earth.
The reasons why the Sun is moving away from the Earth
Brian DiGiorgio, astronomer at the University of California, explains that since the Sun is constantly producing energy, it is also constantly losing mass.
Models of the evolution of stars over time predict that the sun will lose about 0.1% of its total mass before it begins to die.
“This is a lot of dough,” says DiGiorgio. “It has about the same amount of mass as Jupiter.”
The astronomer indicates that our planet is moving away from the star approximately 6 centimeters per year. “This is quite insignificant, especially compared to the normal variation in Earth’s orbital distance, which occurs due to its slightly elliptical orbit, around 3%”, emphasizes DiGiorgio.
In the case of tides on Earth, just as the gravitational attraction of the Moon produces tides on our planet, its gravity attracts the Sun.
Britt Scharringhausenof Beloit College in Wisconsin, points out that this is why the side of the Sun facing Earth is stretched, resulting in a “tidal bulge.”
However, tidal forces have a very weak effect on the orbit of our planet: the Earth moves away, for this reason, barely 0.0003 centimeters per year.
Should we worry?
The more our planet moves away from the star, the more the climate changes. In the words of DiGiorgio, “as the Earth moves away from the Sun, the light of the star becomes dimmer (…) This dimming corresponds to a 0.4% reduction in solar energy reaching our surface.”
However, the University of California astronomer clarifies: “This is relatively small, compared to the normal variations in the brightness of the sun that occur due to the elliptical orbit of the Earth.”
Therefore, there is not much to worry about. At least in the immediate time.
In the next 5 billion years, more changes will be noticed, since by this time, Despite the greater distance from our planet, the brightness of the Sun will increase, slowly increasing the temperatures of the Earth, which directly affects the oceans.
“Stellar evolution models predict that (the Sun) will increase its brightness by approximately 6% every billion years,” emphasizes the astronomer. “This will make the Earth uninhabitable for humans, long before the Sun swallows it.”