Ancient Sun-Like Star Provides Insight on Earth's Death 5 Billion Years From Now
An international team of scientists is trying to take a peak on what will happen to Earth five billion years from now by looking at a 10-billion-year old star with the help of one of the most powerful radio telescopes in the world.
Their findings, described in a paper published in the journal Astronomy and Astrophysics, showed that the star L2 Puppis was very similar to our sun about five billion years ago. This suggests that whatever occurred to L2 Puppis will most likely happen to our sun.
"We discovered that L2 Puppis is about 10 billion years old," said Ward Homan, a researcher at KU Leuven Institute of Astronomy and one of the researchers, in a press release. "Five billion years ago, the star was an almost perfect twin of our Sun as it is today, with the same mass. One third of this mass was lost during the evolution of the star. The same will happen with our Sun in the very distant future."
Using the ALMA radio telescopes, the researchers observed the L2 Puppis located about 208 light-years away from Earth. The 66 individual radio antennas forming the 16-kilometer wide virtual telescopes make it possible for the researchers to look into the L2 Puppis and an orbiting planet 300 million kilometers from the star.
The researchers claim that our sun will experience the same evolution that occurred to L2 Puppis. About five billion years from now, our sun will grow into a red giant star. This red giant will be hundred times larger than its current size. The growing sun will most likely engulf and destroy Mercury and Venus.
As the sun continues to expand, it will experience intense mass loss through a very strong stellar wind. The evolution of the sun will take about seven billion years, before it regress to tiny white dwarf about the size of Earth. Despite being smaller, the researchers noted that the sun will much heavier. One teaspoon of white dwarf materials weighs about five tons.
The next thing to do is to look closer and study the planet orbiting L2 Puppis. The researchers claim that the orbiting planet will be the key in finding out if the rocky core of Earth could survive the red giant phase of the sun.