Earth: are we moving away from the sun? that’s life?

Even though the Sun appears to be a predictable object, with the Earth stable in its revolving motion, this is only an appearance. In fact, the average distance between the Earth and the Sun is not static from year to year. There are variations around an average that is changing over the long term. In which direction?

In reality the Sun is moving away from the Earth slowly. On average, according to NASA, the Earth is 150 million kilometers from the Sun. However, its orbit is not perfectly circular: it is slightly elliptical, or oval, so the distance can vary from 147.1 million to 152, 1 million km, according to NASA. This distance is increasing for two reasons: the loss of mass of the sun and the effects of the tides on the earth.

Nuclear fusion reactions that power the sun convert mass into energy, according to Einstein's famous equation E = mc ^ 2. Since the sun constantly produces energy, it also constantly loses mass . Over the remaining lifespan of the sun – estimated to be around 5 billion years, according to NASA (opens in a new tab) – star evolution models predict that the sun will lose about 0.1% of its total mass before. to start dying, Brian DiGiorgio, an astronomer at the University of California, Santa Cruz, told Live Science in an email.

While 0.1% may not seem like a lot, "that's a lot of mass," DiGiorgio said. "It's about the same amount of mass as Jupiter." Jupiter, in turn, is about 318 times the mass of Earth, according to the Exploratorium (opens in a new tab) in California.

The gravitational pull of an object is proportional to its mass. As the Sun is losing mass, its attraction to Earth is weakening, causing our planet to move away from our star by about 6 centimeters per year. A negligible but objective fact. Let's move on to consider the second factor.

Just as the gravitational pull of the Moon causes tides on Earth, Earth's gravity also pulls on the Sun. This stretches the side of the Sun towards the Earth, giving rise to a "tidal bulge," wrote Britt Scharringhausen. , associate professor of physics and astronomy at Beloit College in Wisconsin, for Cornell University's Ask an Astronomer page (opens in a new tab).

According to NASA, the Sun rotates on its axis about once every 27 days (opens a new tab). Since this rotation is faster than the approximately 365 days it takes for the Earth to complete one orbit around the Sun, the tidal bulge that the Earth generates on the Sun is in front of the Earth. The bulge's mass is associated with a gravitational pull that pushes the Earth forward in its orbit and away from the Sun, Scharringhausen noted, with a similar effect causing Earth's moon to slowly move away from our planet. However, the tidal effect is minimal, at only 0.0003 cm per year.

So all almost fine. there is a departure, but is it very slow and almost not noticeable? No there are problems the same, in our relationship with the sun: evolutionary models predict that the energy emitted by the sun increases by 6% every billion years, so that, progressively, over a very long time, the sun will still do literally boiling the oceans on Earth, making it uninhabitable.

That's life? the one so protected by ecologists? However it will disappear, CO2 or not CO2, unless we follow a completely different path from ecological austerity and energy containment. a technological and industrial push that accelerates evolution allows man, but life in general, to detach himself from the Earth and spread outside.

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The Earth article: are we moving away from the sun? that's life? comes from ScenariEconomici.it .

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This is a machine translation of a post published on Scenari Economici at the URL https://scenarieconomici.it/terra-ci-stiamo-allontanando-dal-sole-e-la-vita/ on Sun, 07 Aug 2022 12:00:50 +0000.