NASA and Cambridge Researchers Imagine What Will Happen When Our Sun Burns Out


When the Sun runs out of fuel, the entire solar system's going to feel it.

First, gravity will force the star to contract, raising the heat inside its core. Then it will expand into a bright red giant. Billions of years later, the dying Sun — which is commonly known as one of our solar system's biggest stars — will start spitting out its outer layers, destroying Earth and any other rocky planets in its path. In a finale of power, the perishing star will suck in and destroy any nearby asteroids. Finally, the debris will settle, forming a delicate ring around the departed star.

The news: Scientists have uncovered important clues as to what might happen when the Sun burns out. 

Using chemical samples from the stars' atmospheres, researchers at Cambridge University and NASA created a picture of what two star-systems may have looked like before their stars went out. The work appeared in the Monthly Notices of the Royal Astronomical Society.

By sampling the atmospheres of two dead stars in the Hyades Cluster, a grouping of hundreds of stars 150 light years away, the scientists pieced together a play-by-play scenario of the events that followed their stars' death. (From our Earthly perspective, the Hyades forms the V-shaped bull head in the Taurus constellation.) To their surprise, they found silicon — the rocky material that makes up the Earth and other terrestrial planets in our solar system — dotting the Hyades stars' surroundings.

Top photo: An artist's impression of a burned-out star as it accumulates rocky debris left behind by remaining planets. The star was observed by the Hubble Telescope in the Hyades Cluster. In the lower right, an asteroid can be seen falling toward a Saturn-like disk of dust that is encircling the dead star. Image Credit: NASA, ESA and G. Bacon (STScI)

Next photo: Hyades Cluster. Image credit: Wikimedia Commons

An artist's concept of a dead star surrounded by the bits and pieces of a disintegrating asteroid. Image credit: NASA/JPL-Caltech

The Hubble Space Telescope. Image credit: NASA

If Earth-like planets really did exist in these systems (as the silicon would seem to indicate), the dead stars provide important clues as to what might happen when our Sun burns out. But sit tight, that's not set to happen for another five billion years.

This is what they think happened: When stars begin to give out, the contraction and expansion they undergo causes their masses to fluctuate wildly. When one mass of one planet in a solar system changes, it throws off the precarious gravitational balance of surviving planets and the asteroids between them. When the asteroids swing towards the dead star, they are shattered by its pull, and their scattered remains may settle to Saturn-like rings that circle the inert star.

Here's why it matters: This was one of the first studies of its kind to look at the rocky material of planets outside our solar system. By piecing together the birth and death of stars in other solar systems, scientists hope to understand how our solar system formed — and what will happen when our Sun perishes. And the better we understand our solar system, the better we can understand how the Earth fits into it and our relationships with other planets and the Sun.