What If Dark Energy Was Usable?
The laws of physics are strange, and there are lots of things we don’t yet know about
how our universe works. Most mysterious of all is the fact that completely unknown forces
are governing our reality. Forces so unexplained that we don’t even know what they are, let
alone what they might be capable of.
This is Unveiled, and today we’re answering the extraordinary question: what if dark energy
was usable?
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The matter and energy that we can see and interact with makes up only about 5% of what’s
out there. Yes, that includes every star, every planet, every interstellar cloud, and
every black hole in the observable universe. The other 95% isn’t just empty space, either.
Or rather, it seems to be empty space, but there’s something bizarre within that space
that our instruments can’t detect: dark energy and dark matter.
Dark matter makes up 27% of the universe’s mass-energy, much more than ordinary matter,
while dark energy makes up a whopping 68%. We know that dark matter exists due to its
gravitational effects. Without it, galaxies wouldn’t be spinning so fast, or even able
to form and hold together at all. Dark energy is similarly elusive, and has never been detected,
but it’s the best way we know of to explain the accelerating expansion of the universe.
Dark energy is thought to be distributed uniformly throughout space, permeating the universe.
Dark energy is a relatively new idea. While it has a precursor in Einstein’s “cosmological
constant”, proposed in 1917, the term “dark energy” was first coined by cosmologist
Michael Turner in 1998. That year, scientists realized that the universe wasn’t expanding
at the rate they’d predicted. We’ve known that the universe is expanding ever since
astronomer Edwin Hubble discovered that the more distant a galaxy, the faster it’s moving
away from us. Before the 1990s, however, it was generally assumed that expansion was slowing
down – after all, it was thought to be residual from the Big Bang, which happened around 13.8
billion years ago. However, attempts to measure the deceleration using supernovae discovered
the exact opposite - that expansion was speeding up!
Scientists realized that something must be counteracting gravity and fuelling this expansion,
dubbing that something “dark energy”. Dark energy could be a lot of things, though.
Some think that it is indeed a cosmological constant, an intrinsic property of space.
Others postulate that it’s a fifth fundamental force of the universe, or “quintessence”.
Or it could be a sort of fluid that’s one and the same as dark matter and naturally
fills empty space. All we know for sure is that it’s responsible for the universe’s
expansion. The rate of expansion is what tells us that it makes up 68% of everything. Depending
on the amount of dark energy in the universe, it could keep expanding forever. The more
space there is, the more dark energy, and the more expansion, resulting in a “Big
Rip” that tears ordinary matter apart.
There’s still a long time however before that happens. This means that we do have enough
time as a species to develop a technology that can detect and interact with dark energy
– if such a thing is possible. Whatever dark energy is, it must be very powerful to
accelerate the universe’s expansion, so if there’s a way to harness it, it could
be a game-changer.
If we figured out how to use it, it would easily be the greatest discovery in history.
Dark energy could become humanity’s main power source. It’s so abundant that it might
as well be infinite and exists literally everywhere where there’s space. We could potentially
set up large machines used to extract it and mine space itself for fuel. It would make
deep space travel and colonization much easier, too, since ships could forego carrying fuel
and just suck up energy from the space around them. Not having to carry fuel would make
ships lighter, faster, and capable of travelling vast distances without stopping. It would
also make colonies much more independent and enable us to build them anywhere, even just
floating around outside star systems and between galaxies.
There are a few problems with this idea, though. Some people think it’s unethical to mine
space for resources. Already, people argue that mining other planets and moons might
be morally wrong or unsustainable, and similar thinking could be applied to dark energy extraction.
It would also depend heavily on whether our universe is expected to end in a Big Rip or
the opposite, a Big Crunch, which partially depends on just how much dark energy there
is in the universe. On one hand, if it’s going to end in a Big Crunch, then mining
dark energy could potentially hasten the end of the universe. On the other hand, if we’re
heading towards a Big Rip, mining dark energy for all we’re worth could actually prolong
the life of the universe!
If we could use or manipulate dark energy on a vast scale, we might be able to slow
down expansion enough to delay or prevent the Big Rip from happening. Of course, it
could well be impossible for humans to extract anywhere near enough dark energy to do this,
but we can hope. Space’s expansion will also bring about a different problem when
it comes to interstellar travel; in 100 billion years it will have expanded so much that we
won’t even be able to see other galaxies from the Milky Way, let alone travel to them.
But by siphoning up dark energy, an advanced civilization might be able to slow this down,
or even reverse it - although again, this may end up hastening the Big Crunch if we
go too far in the other direction.
Though humans might not manage it, if an advanced civilization somewhere was able to develop
the tech to harness dark energy, they wouldn’t just get an unlimited and eternal power source;
they’d also have the power to save or end the universe at the tip of their fingers – if
they have fingers. And that’s what would happen if dark energy was usable.
What do you think? Is there anything we missed? Let us know in the comments, check out these
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