• Choose a category
• All
• Classic-Fiction

* * *

Just as the ship’s iron will eventually rust and be carried away by the desert winds, so we think the last matter in the Universe will eventually be carried off into the void.

* * *

One of the ships to end her days here was the Eduard Bohlen, a 91-metre (300-foot), 2,272-tonne steamship that ran aground here on the 5 September 1909 on a journey from Germany to West Africa. A century’s shifting sands have carried her hundreds of metres inland and the Atlantic winds have attacked her carcass, leaving her rusting and skeletal. When we arrive she is guarded by a phalanx of jackals who are less wary of us than I expected. She forms an abstract backdrop to our story; the symbolism is immediate, brutal even, and for me surprisingly powerful. These wrecks, complex structures dismantled by the passage of time, are like our last stars.

The Skeleton Coast: one of the most inhospitable places on Earth, where humans have perished for centuries, and where only jackals and the strongest life forms remain.

In the far future of the cosmos, the last remaining beacons of light will no more be permitted to evade the second law of thermodynamics than the Eduard Bohlen. Even the white dwarfs must fade as the laws of physics methodically dismantle the Universe. Slowly, as the glowing embers of the last stars lose their warmth to space, they will cease to emit visible light. After trillions of years, the final beacons burning in the cosmic sky will turn cold and dark – their remnants are known as black dwarfs.

Black dwarfs are dark, dense, decaying balls of degenerate matter. Nothing more than the ashes of stars, they take so long to form that after almost 14 billion years, the Universe is currently too young to contain any at all. Yet despite never seeing one, our understanding of fundamental physics allows us to make concrete predictions about how they will end their days. Just as the iron that makes up the ships of the Skeleton Coast will eventually be carried away by the desert winds, so it is thought that the matter inside black dwarfs, the last matter in the Universe, will eventually evaporate away and be carried off into the void as radiation, leaving nothing behind. The processes by which matter might, given enough time, decay, are not understood. Physicists need a more advanced theory of the forces of nature, known as a Grand Unified Theory, to speak with certainty about the behaviour of protons, neutrons and electrons over trillion-year timescales. There are reasons to expect that such a theory may exist, and that a mechanism for even the most stable sub-atomic particles to decay into radiation might be present in nature. For this reason, experiments to measure the lifetime of protons are ongoing in laboratories around the world, but as yet nobody has observed proton decay, and we are therefore now in the realm of speculation. But here is one possible, and given our understanding of physics today, probable, story of how our universe will end.

NASA

This composite X-ray image from the Chandra X-ray Observatory shows gas blowing away from a central supermassive black hole in the active galaxy NGC 1068.

NASA

* * *

Once the last remnants of the last stars have decayed away to nothing…the story of our universe will finally come to an end.

* * *

In trillions of years, our universe will be littered with black dwarfs. From the ashes of stars, dark, dense and decaying balls of degenerate matter will form.

With the black dwarfs gone, there will not be a single atom of matter left in the Universe. All that will remain of our once-rich cosmos will be particles of light and black holes. After an unimaginable expanse of time, it is thought that even the black holes will evaporate away, and the Universe will consist of a sea of light; photons all tending to the same temperature as the expansion of the Universe cools them towards absolute zero. When I say unimaginable period of time, I really