When the Sun goes out: scientists predicted a dark date in human history

Yulia LoseynkoLife
Astronomer Albert Seylstra explains how the Sun will become the equivalent of the planetary Cat's Eye Nebula

We are used to taking the Sun for granted, as a certain constant of life. However, astronomers have long warned that our sun is not eternal and that sooner or later it too will die.

Moreover, a team of astronomers from Poland, Great Britain and Brazil has predicted when and how it will go out. Article about it they published in a scientific journal Nature Astronomy, writes edition Science Alert. According to their predictions, the Sun will become a planetary nebula - a shell of ionized gas, in the center of which is a white dwarf, a small dead star, shining not because of the energy of constant thermonuclear reactions, but only through the gradually losing thermal energy. However, humanity will never see this again.

How will the Sun die?

Our luminary is now about 4.6 billion years old and is classified as a yellow dwarf. In about 5 billion years, it will begin to turn into a red giant. The star's core will shrink and its outer layers will expand. The surface of the Sun is predicted to reach the orbit of Mars, absorbing the Earth.

And in another 5 billion years, the red giant will begin to shrink into a white dwarf. "When a star dies, it ejects into space a mass of gas and dust known as its envelope. The envelope can make up to half the star. This opens up the star's core, which by this point runs out of fuel, and it eventually shuts down before finally dying," explained astrophysicist Albert Zeilstra of the University of Manchester in the United Kingdom, one of the authors of the paper.

In the state of a white dwarf, the Sun will be a short time by astronomical standards - about 10,000 years. During this period, planetary nebulae remain visible to the outside observer. Sometimes, the actual dead star is even brighter than when it was active. But then the core cools and the star fades away, and the matter from the star spreads out across the Universe, enriching it with carbon, oxygen, nitrogen, and other elements.

Why won't people see the death of the Sun?

The authors of the study confidently state - even at the moment when the Sun begins to turn into a red giant, there will be no life on Earth anymore. The point is that the brightness of our star grows by 10% in about a billion Earth years. Exactly one billion years will be enough for the oceans to evaporate and for the planet's surface to become too hot for water formation. So the Earth would become completely uninhabitable.

However, mankind still has some chance to find a new home in the depths of the universe during this time, and to invent a way to get there. But scientists have certain doubts about this. As wrote OBOZREVATEL, experts NASA put forward a theory that explains why we have not yet come into contact with extraterrestrial civilizations and predicts a rather tragic fate.

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