Dark energy is a hypothetical force that scientists rely on to explain why the Universe expands at an accelerating rate. Discover how a new theory challenges dark matter’s existence based on magnetism.
I was fascinated by magnets as a child. We had a pair of those standard red and white horseshoe magnets in the toy box when I was growing up. The magnets’ polarity was intriguing, mainly how opposite poles attract and like poles repel each other.
It was also fun to explore what was magnetic and what wasn’t. It didn’t take long to work out that only metals are magnetic, but it was harder to grasp why a nickel was magnetic while a dime wasn’t.
Later on, I learned a few magic tricks that involved hidden magnets. I managed to fool my family and friends, at least to the point where they couldn’t explain how my illusions worked.
ELECTRONS AND PROTONS ATTRACTED WITH OPPOSING CHARGES
In high school, I learned a few things about atoms and molecules. In particular, I found out that protons and electrons attracted each other with opposing charges. That’s what we’ll be talking about in this post.
In the late 90s, scientists including Saul Perlmutter and Martin Reese discovered that not only was the Universe expanding, but its expansion was also accelerating. This was difficult to explain, but it implied that some sort of energy was at work.
For the Universe to grow at an accelerating rate, some sort of extra energy has to be enhancing the force of the original Big Bang. The power also has to be repulsive to counteract the force of gravity.
DUBBED THIS UNSEEN, UNDETECTED FORCE “DARK ENERGY”
Scientists couldn’t explain this power, and in that way, it was similar to dark matter. So, they dubbed this unseen, undetected force “dark energy.” That’s been the conventional wisdom for over two decades now.
A new study from the University of Copenhagen challenges that standard model. This is an audacious claim because current science tells us that dark energy makes up 70% of our Universe.
Dark matter seems to make up 25% of the Universe. The conventional matter that we perceive in daily life accounts for only 5% of the known Universe.
SEVENTY PERCENT OF THE UNIVERSE DOESN’T EVEN EXIST
If this new theory is accurate, 70% of the Universe scientists rely on to explain its expansion doesn’t even exist. Instead, according to the researchers, properties of dark matter are causing the acceleration we observe.
Steen Harle Hansen is an associate professor at the Niels Bohr Institute’s DARK Cosmology Centre. He explained the implications of the study this way.
“If what we discovered is accurate, it would upend our belief that what we thought made up 70 percent of the Universe does not actually exist. We have removed dark energy from the equation and added in a few more properties for dark matter. This appears to have the same effect upon the Universe’s expansion as dark energy.”
“SAME EFFECT UPON THE UNIVERSE’S EXPANSION AS DARK ENERGY”
The team arrived at their novel conclusion using computer modelling. Investigators used the cosmology applications MUSIC and RAMSES to simulate various initial conditions and calculate the results based on a range of assumptions.
“We developed a model that worked from the assumption that dark matter particles have a type of magnetic force and investigated what effect this force would have on the universe,” Professor Hansen explained. “It turns out that it would have exactly the same effect on the speed of the universe’s expansion as we know from dark energy.”
There’s a principle in logic called Ockham’s Razor. It comes from the 14th-century philosopher William of Ockham.
PRINCIPLE IN LOGIC CALLED OCKHAM’S RAZOR
Scientists and philosophers remember Ockham for one influential idea. He explained that when we have two explanations for a phenomenon, the more straightforward explanation that covers all the facts is more likely to be true.
This new view of why the Universe’s expansion accelerates eliminates the “need” for dark energy. So, in that sense, it’s a much simpler idea than the standard model.
On the other hand, it also adds properties to dark matter without observing what dark matter is. The theory relies on the widely held assumption that dark matter consists of particles just as ordinary matter does.
“WHAT IF DARK MATTER HAD SOME QUALITY ANALOGOUS TO MAGNETISM?”
As Professor Hansen put it, “We don’t know much about dark matter other than that it is a heavy and slow particle. But then we wondered—what if dark matter had some quality that was analogous to magnetism in it?”
At this point, nobody has ever seen a particle of dark matter. Scientists have surmised that dark matter particles mustn’t interact much with light or other particles, and they must have mass.
They’ve come up with a hypothesis called Weakly Interactive Massive Particles (WIMPS). The trouble is that, despite their best efforts, nobody has ever seen or even detected anything remotely resembling a WIMP.
DOES AWAY WITH HYPOTHETICAL FORM OF ENERGY
So, from an empirical point of view, it’s hard to say which idea best meets the test of Ockham’s Razor. The new theory does away with a hypothetical form of energy. Still, in exchange, it attributes speculative properties to a hypothetical particle.
“We know that as normal particles move around, they create magnetism,” explained Professor Hansen. “And, magnets attract or repel other magnets—so what if that’s what’s going on in the Universe? That this constant expansion of dark matter is occurring thanks to some sort of magnetic force?”
This explanation is undoubtedly valid logically. However, until someone finds a way to detect or observe dark matter, the story of our place in the Universe still has missing pieces.
EXPLANATION IS CERTAINLY VALID LOGICALLY
Every culture has a story of how the Universe began, how it works, our role within it, and how it will end. Until we can explain why our Universe is expanding at an accelerating rate, our modern culture will continue to lack a coherent cosmology.
Professor Hansen wrapped up by saying, “As far as our current knowledge, our ideas about dark matter with a type of magnetic force and the idea about dark energy are equally wild. Only more detailed observations will determine which of these models is the more realistic. So, it will be incredibly exciting to retest our result.”
We always have more to learn if we dare to know.
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