Will the Sun become a black hole? No, it's too small for that! The Sun would need to be about 20 times more massive to end its life as a black hole.
No. Stars like the Sun just aren't massive enough to become black holes. Instead, in several billion years, the Sun will cast off its outer layers, and its core will form a white dwarf - a dense ball of carbon and oxygen that no longer produces nuclear energy, but that shines because it is very hot.
Instead, the Sun will become a dense stellar remnant called a white dwarf. But if, hypothetically, the Sun suddenly became a black hole with the same mass as it has today, this would not affect the orbits of the planets, because its gravitational influence on the solar system would be the same.
So, the Sun won't become a black dwarf for trillions of years — and, in fact, no black dwarfs exist yet, simply because the universe has not been around long enough to allow even the earliest stars to reach this stage.
However, the 2018 study used computer modeling to determine that, like 90 percent of other stars, our Sun is most likely to shrink down from a red giant to become a white dwarf and then end as a planetary nebula. "When a star dies it ejects a mass of gas and dust – known as its envelope – into space.
Within a few days, however, the temperatures would begin to drop, and any humans left on the planet's surface would die soon after. Within two months, the ocean's surface would freeze over, but it would take another thousand years for our seas to freeze solid.
Four billion years from now, the increase in Earth's surface temperature will cause a runaway greenhouse effect, creating conditions more extreme than present-day Venus and heating Earth's surface enough to melt it. By that point, all life on Earth will be extinct.
Eventually, the entire contents of the universe will be crushed together into an impossibly tiny space – a singularity, like a reverse Big Bang. Different scientists give different estimates of when this contraction phase might begin. It could be billions of years away yet.
In approximately five billion years, our own sun will transition to the red giant phase. When it expands, its outer layers will consume Mercury and Venus and also reach Earth.
The Sun as a red giant will then... go supernova? Actually, no—it doesn't have enough mass to explode. Instead, it will lose its outer layers and condense into a white dwarf star about the same size as our planet is now.
No supernova, no black hole
Our sun isn't massive enough to trigger a stellar explosion, called a supernova, when it dies, and it will never become a black hole either. In order to create a supernova, a star needs about 10 times the mass of our sun.
Located just under 1,600 light-years away, the discovery suggests there might be a sizable population of dormant black holes in binary systems. The black hole Gaia BH1, seen in this artist's concept near its Sun-like companion star, is the closest black hole to Earth discovered so far.
So what will happen to the Sun? In some 6 billion years it will end up as a white dwarf — a small, dense remnant of a star that glows from leftover heat. The process will start about 5 billion years from now when the Sun begins to run out of fuel.
Analyzing the data provided by the Gaia Spacecraft, scientists have concluded that the Sun will reach a maximum temperature at approximately 8 billion years of age, then it will cool down and increase in size, becoming a red giant star. At the age of 1011 billion years, the Sun will reach the end of its life.
In our solar system, the closest planets to the sun, Mercury and Venus, are expected to get swallowed by the growing sun entirely. Earth, while it may survive, will be so scorched that it will become completely uninhabitable.
Mercury will be swallowed by the Sun during its first red giant phase. Venus may survive the first phase, but will be consumed during the second giant phase. In all but the direst scenarios, Mars will survive the Sun's final stages of evolution.
In their paper, the authors consider a hypothetical example with w = −1.5, H0 = 70 km/s/Mpc, and Ωm = 0.3, in which case the Big Rip would happen approximately 22 billion years from the present. In this scenario, galaxies would first be separated from each other about 200 million years before the Big Rip.
As the universe keeps ballooning, stars, including our own sun (after first becoming a red giant and incinerating the Earth), and even black holes will eventually radiate away all their energy, and the universe will go dark, forever.
Observations suggest that the expansion of the universe will continue forever. The prevailing theory is that the universe will cool as it expands, eventually becoming too cold to sustain life. For this reason, this future scenario once popularly called "Heat Death" is now known as the "Big Chill" or "Big Freeze".
By 2050 , the world's population will exceed at least 9 billion and by 2050 the population of India will exceed that of China. By 2050, about 75% of the world population will be living in cities. Then there will be buildings touching the sky and cities will be settled from the ground up.
The upshot: Earth has at least 1.5 billion years left to support life, the researchers report this month in Geophysical Research Letters.
Humans have certainly had a profound effect on their environment, but our current claim to dominance is based on criteria that we have chosen ourselves. Ants outnumber us, trees outlive us, fungi outweigh us. Bacteria win on all of these counts at once.
The gravitational pull of the moon moderates Earth's wobble, keeping the climate stable. That's a boon for life. Without it, we could have enormous climate mood swings over billions of years, with different areas getting extraordinarily hot and then plunging into long ice ages.
It is the pull of the Moon's gravity on the Earth that holds our planet in place. Without the Moon stabilising our tilt, it is possible that the Earth's tilt could vary wildly. It would move from no tilt (which means no seasons) to a large tilt (which means extreme weather and even ice ages).