How long will the Earth exist and when will humans become extinct?

Arabia Weather - Today, the sun is a primary source of gravity and energy. But one day, it will cause the Earth to disappear. As the central star in the solar system ages, its life cycle will eventually consume our blue marble.

So, how long does the Earth have until it is swallowed by the Sun?

Expected time of death : Several billion years from now, but life on Earth will end much sooner than that.

Experts told Live Science that the Earth will become uninhabitable for most living organisms in about 1.3 billion years due to the natural evolution of the Sun. Humans will likely drive themselves (and countless other species) to extinction within the next few centuries if the current pace of climate change caused by human activity, or as a result of nuclear war, is not mitigated.

The death of the sun

Our planet's final curtain is tied to the evolution of the Sun. "Earth will likely have 4.5 billion years before the Sun becomes a large red giant star and then engulfs Earth," Ravi Kopparapu, a planetary scientist at NASA's Goddard Space Flight Center, told Live Science. A red giant star forms in the final stages of stellar evolution, when a star runs out of hydrogen to fuel its nuclear fusion and therefore begins to die, according to the European Space Agency.

Once fusion stops, gravity takes over. The helium core will begin to compress under gravity, which will raise the temperature. This increase in temperature will cause the sun's outer plasma layer to expand significantly. "The Sun will swell at least to the size of Earth's orbit," Kopparapu said.

What is the fate of the Earth?

But the Earth probably won't last those 4.5 billion years, and it certainly won't be the Earth as we know it.

Experts said: "You do not have to wait until the outer layers of the Sun reach the Earth." The planet will experience intense heat long before the Sun finishes turning into a red giant star. As the Sun's temperature rises due to its dying process, "the oceans will evaporate, the atmosphere will eventually disappear, and then the tidal forces caused by the Sun's gravity will tear apart the Earth."

Approximately 1.3 billion years from now, “humans will no longer be able to survive physiologically, in nature, on Earth” due to persistent hot and humid conditions. In about 2 billion years, the oceans may evaporate when the sun's brightness is about 20% brighter than it is now, Kopparapu said. Some life forms may survive up to this point - such as "extremophiles" that live near hydrothermal vents on the ocean floor - but not humans, Kopparapu said.

“Humans — and all complex life forms — are in desperate need of this,” Rodolfo Garcia, a doctoral student in astronomy and astrobiology at the University of Washington, told Live Science. For humans, for example, a fever of just 6 degrees Fahrenheit (3.3 degrees Celsius) is life-threatening, he added.

Kopparapu said dangerous humid temperatures — a combination of temperature, humidity, wind speed, sun angle and cloud cover — at which humans can no longer cool down by sweating are very imminent, just a few degrees away.

The threshold for a humid environment for humans was first predicted to be 95°F (35°C). However, recent research suggests that humid environment temperatures of up to 86°F (30°C) can be fatal.

Some places on Earth have already reached humid temperatures exceeding 90°F (32°C) on multiple occasions, and climate models predict that 95°F (35°C) will be a regular occurrence in regions like the Middle East by the end of the century. At this temperature, animals that sweat would cook in the heat, Kopparapu said. In essence, our greenhouse gases are poised to threaten life and society on Earth long before the sun dies.

“If we are talking about human life, the next 100 years are going to be interesting,” Kopparapu said.

Source: livescience