Space & Astronomy

Scientists reveal the Sun's ultimate fate

By T.K. Randall
May 8, 2018

Image: Coronal Mass Ejection
Credit: NASA Goddard Space Flight Center / CC BY 2.0 (adapted) At 4.6 billion years old, our Sun is vital to the survival of all life on Earth and always has been.

Originally formed from the gravitational collapse of matter within a large molecular cloud, our star is 109 times larger (in terms of diameter) and 330,000 times more massive than the Earth.

In around 5 billion years from now, it will expand to over 250 times its current size, swallowing up Mercury, Venus and the Earth as it becomes what is known as a red giant.

Exactly what will happen next however has long remained a topic of debate among scientists, but now an international team of astronomers believe that they may have finally found the answer.In most cases, as a main-sequence star dies, it will collapse from a red giant in to a white dwarf, producing a glowing ring of gas and dust known as a planetary nebula.

Using a new model that can predict the life-cycle of stars, scientists have now been able to confirm that this is likely to happen in the case of the Sun as well.

"When a star dies it ejects a mass of gas and dust - known as its envelope - into space," said Professor Albert Zijlstra from the University of Manchester.

"This reveals the star's core, which by this point in the star's life is running out of fuel, eventually turning off and before finally dying. It is only then the hot core makes the ejected envelope shine brightly for around 10,000 years - a brief period in astronomy."

"This is what makes the planetary nebula visible. Some are so bright that they can be seen from extremely large distances measuring tens of millions of light years, where the star itself would have been much too faint to see."

Source: Sky News

Tags: Sun, Red Giant, Nebula