The Last Thing to Ever Happen in the Universe

The Last Thing to Ever Happen in the Universe

The Peaceful Decline of the Cosmos

The universe today is a vibrant, thriving place, full of exciting phenomena and activity. But as the eons pass, the night will eventually turn dark, and everything that once was will peacefully sleep forever. What, then, is the very last thing that will ever occur in our universe?

To find the answer, we must travel to the unimaginably distant future and witness the final stages of the cosmos. It’s a journey that will take us through the gradual decline of the stars, the slow death of black holes, and the bizarre physics of black dwarfs – the last remnants of once-mighty celestial bodies.

The Slow Decline of the Stars

Our universe began with a messy birth, a swirling cloud of hot hydrogen and helium gas. From this primordial soup, the first generation of stars emerged – massive, violent behemoths that forged new elements and then exploded, seeding the cosmos with the building blocks of future generations.

Over time, countless stars were born and died, cycling matter around and refining the available gas. But not all of this material was returned to the universe. With each new cycle, more and more of the gas was locked away in the form of:

• Red dwarfs – small, long-lived stars that burn their fuel slowly and don’t give their gas back when they die, turning into white dwarfs instead.
• Neutron stars and black holes – the incredibly dense remnants of massive stars.

As a result, the overall amount of available gas for new star formation has been steadily declining. Today, over 90% of the stars that will ever exist have already been born.

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The End of the Stars

Over the next few hundred billion years, the universe will continue to be a vibrant and exciting place, with ample opportunities for galactic exploration and discovery. But step by step, the stars will begin to die out.

First, the large stars and stars like our own Sun will reach the end of their lives. Eventually, almost all the stars in the cosmos will be red dwarfs, slowly fading away. In a few trillion years, the cosmic gas will finally run out, and the universe will enter a new phase.

The Bizarre Physics of Black Dwarfs

At this point, the vast majority of the mass in every galaxy will be locked up in one of three forms:

• White dwarfs – the dense, dim corpses of old stars, about the size of Earth but with the mass of half the Sun.
• Neutron stars – even denser objects, with the mass of the Sun compressed into a sphere just 20 kilometers across.
• Black holes – the most extreme objects in the universe, where gravity is so strong that not even light can escape.

Only about 10% of the mass will remain in the form of gas giants and failed stars known as brown dwarfs.

But even the white dwarfs won’t last forever. Slowly, over the course of at least 10 trillion years – more than 700 times the current age of the universe – they will lose their heat and turn into black dwarfs: spheres of matter as cold as the vacuum of space itself, invisible against the dark backdrop of the cosmos.

The Weird Physics of Black Dwarfs

So, what keeps these black dwarfs from collapsing into black holes? It turns out that the answer lies in the bizarre physics that governs matter at such extreme densities.

Inside a black dwarf, the pressure is so immense that the normal rules of matter no longer apply. Electrons can’t combine with nuclei to form atoms – instead, the nuclei are locked into a rigid lattice, with the electrons forming a plasma in between.

This degenerate matter behaves in strange ways. Imagine it like a crowded subway train – the “passengers” (the electrons) are forced to sit and stand close together, which they hate. So they push outward, using their quantum mechanical properties to counteract the crushing force of gravity and hold the star up.

But this delicate balance can’t last forever. Over unimaginably long timescales, the nuclei in the black dwarf will slowly begin to fuse together through a process called quantum tunneling, creating heavier and heavier elements.

The Last Thing to Ever Happen

Eventually, this process will lead to the formation of radioactive nickel-56. When this nickel decays, it releases positrons – the antimatter counterparts of electrons. These positrons then annihilate with regular electrons, destroying the very particles that were holding the black dwarf together.

For the most massive black dwarfs, this is catastrophic. Bit by bit, the star turns into a sphere of iron, losing more and more of the electrons that were keeping it from collapsing. And then, after at least 10^1000 years – a number so absurdly large that it’s almost impossible to comprehend – the black dwarf can no longer support its own weight.

The last thing to ever happen in the universe is this: the black dwarf undergoes an uncontrolled collapse, imploding and then exploding in a final, brilliant supernova. For a brief moment, the empty universe is filled with light once more, before the darkness returns, permanent and absolute.

And then, it’s over. The universe may now be truly dead, with no more interesting events to come. But don’t be too bummed out – this final act is so far in the future that “forever” hardly does it justice. For now, there are still plenty of fascinating things to discover and explore in our vibrant, living cosmos.

Conclusion

The universe we live in today is a vibrant, thriving place, full of wonder and possibility. But as the eons pass, the night will eventually turn dark, and everything that once was will peacefully sleep forever.

What, then, is the very last thing that will ever occur in our universe? It’s a question that takes us on a journey through the gradual decline of the stars, the slow death of black holes, and the bizarre physics of black dwarfs – the last remnants of once-mighty celestial bodies.

Ultimately, the answer lies in the unimaginably distant future, when a single black dwarf, after at least 10^1000 years, will finally collapse in a brilliant supernova – the last interesting event the universe will ever see.

But don’t be too disheartened. This final act is so far away that “forever” hardly does it justice. For now, there are still countless fascinating things to discover and explore in our vibrant, living cosmos. And with the help of resources like KiwiCo and the Kurzgesagt YouTube channel, you can start your own journey of scientific exploration and discovery today.