Earth’s Ultimate Fate

February 14, 2000

It happens all around us in the universe. Stars, many like our own sun, are shrinking, exploding and eventually dying. Everything dependent on these stars suffers a related fate. It's the laws of physics and natural evolution of our universe.

The American Association on the Advancement of Science says Earth will ultimately either "dry up, burn up or freeze" based on continuing scientific research on the Earth's ultimate fate. This is because the Earth's sun is becoming brighter and hotter, on its way to becoming a white dwarf ... billions of years from now. But even before then, the Earth's temperature will rise to the point where the planet will begin to lose its water.

In an interview with MSNBC, Pennsylvania State University Professor of Geosciences, James F. Kasting, said that astronomers have long known that the sun would meet this fate -- and Earth along with it, and that it could happen in five billion years. However, a more pessimistic scientific model indicates the oceans could evaporate in about 1.2 billion years.

Dr. Kasting explains that the warmer temperatures will cause vital carbon dioxide gases -- essential for plant life -- to be absorbed by the oceans. Plant life will eventually die off as will all life dependent on plants for survival.

In yet another scenario, according the MSNBC report, the sun may expand into a giant ball of burning hydrogen as it exhausts its fuel, incinerating the inner planets of Mercury, Venus, Earth and Mars. Before that, in about 3.5 billion years, the sun will be hot enough to burn up all life forms on Earth, with the exception of some bacteria. And yet, according to University of Michigan Physics Professor Fred Adams, Earth could be jettisoned out of its orbit into deep space due to the disruption of the sun's gravity and the gravity of a passing star. In this case, the Earth would freeze as it spins through space without its sun.

This is a simple description of the natural evolution of our planet and solar system, like all others in the universe. While this fate will eventually meet all stars and planets, new solar systems are being born that will go through the same cycles. And a billion years can allow for some remarkable and fascinating developments that will ensure the perpetuation of Earth's lifeforms within our vast universe. As NASA's Hubble Telescope has confirmed, the expansion of the universe, which has been known since the 1920s, is likely to continue forever.

To learn more about the life and death of stars, visit NASA's Universe 101.