On November 2018, scientists published a paper that suggested Earth was directly in the path of a hurricane comprised of mysterious cosmic forces that can change the way we understand the universe.
No, that’s not the plot of the next Marvel movie, this is real life. Researchers from the American Physical Society released an extensive study predicting that the solar system would soon be, if not already, engulfed by a “dark matter storm”. This might all seem scary, if most people didn’t know what dark matter is.
What is Dark Matter?
Short answer? Scientists aren’t entirely sure.
Long answer? Well…
To explain dark matter, we need to look at the bigger picture, more particularly, the biggest picture of them all: the universe. The universe isn’t just vast; there’s also so many things about it that we don’t understand. There are things and events in the universe that just seem to defy the laws of physics that we’ve theorized.
One specific instance are galaxies. A galaxy is a collection of stars and planets and interstellar gas spanning hundreds of thousands of light years. All these stars and planets and interstellar matter are bound together by gravity, and everything in the galaxy spins around a galactic core, the rotational center of galaxies.
Simple enough, but here’s where it gets a little weird: on Earth, things on the edge of a spinning object move relatively slower than things near the center. It makes sense, then, that galaxies would behave in the same manner.
Unfortunately, it doesn’t. Upon observation, scientists found that stars and other interstellar objects near the edge of the Milk Way galaxy actually spin faster than scientists expected. This sparked intense study as to why this is, and what scientists found, or rather not found, baffled them.
It wasn’t just the fact that stars on the edge of a spinning galaxy were moving faster than expected, it was the fact that they were orbiting that center in the first place. Of course, the most logical explanation to that would be gravity. However, remember that the universe is vast, and we mean melt-your-brain vast: there’s no way that there’s an object in the center of the galaxy big enough to generate that kind of gravity.
But gravity is the glue that holds the cosmos together, so it has to be that. Even if you take into account the individual gravitational pulls of every planet, gas cloud, black hole, and other star dust, it’s simply not enough to generate enough gravity to keep the galaxy from flinging itself apart.
And so, to make up the difference, scientists theorized the existence of a theoretical particle: dark matter. An ominous and frankly unimaginative name, dark matter is basically all the unaccounted-for matter in the universe, the invisible thing that’s creating all this cosmic glue. The name comes from the fact that dark matter is, well, dark: we can’t see it, nor observe it directly, but it’s there. We think. Maybe.
Detecting something you can’t see or perceive on any sensory level requires some creative thinking: rather than measuring something invisible, you measure its effect on things you can see. Recent studies by scientists from all over the world have yielded some insight into the existence of dark matter by measuring everything they think it has had an effect on, from unexplained distortions of light and the gas filaments that connect scattered groups of galaxies, and even the temperature fluctuations in the cosmic microwave background (also known as CMB, the lingering after-effect of the Big Bang).
Despite the lack of evidence, scientists do have a few theories as to what dark matter really is:
- Massive Compact Halo Objects – also known as MACHO (clever!), these are interstellar objects that are large enough to bend gravity, and subsequently bend light, around them, rendering them invisible. While this might seem like the most logical explanation, it’s also the one that is less likely: there just simply wouldn’t be enough MACHO’s in the universe to explain galactic rotation or the temperature fluctuations in the CMB.
- Weakly Interacting Massive Particles – also known as WIMPS (get it?! Because the other one was MACHO! Scientists are funny), these are theoretical objects the size of atoms or subatomic particles that don’t bend or absorb light the way we think they should. Currently, this is the most accepted school of thought amongst physicists. There’s just one problem: it doesn’t make sense.
WIMPS are the theory of choice because there is precedent for them: neutrinos. Neutrinos are particles so light (they have almost-zero mass) that they are rarely, if at all, able to make an impact or even interact with anything else in the universe.
Ironically, the WIMPS theory is given weight by neutrinos, a near-massless particle that is abundant in the universe and has been both proven to exist and observed by scientists. However, the problem begins with the fact that, if WIMPS were to exist, they would have to have much more mass than a neutrino to have any kind of gravitational pull, but they would have to be smaller than neutrinos for us to have trouble detecting them. It’s quite the conundrum.
So again, we go back to the short answer to this question: scientists aren’t quite sure what dark matter is. They have some theories, they have some guesses, but until we’re able to acquire hard evidence via new technology or a new way of calculating gravitational anomalies and light distortions, it remains unexplained. It might as well be magic.
So What’s This Dark Matter “Storm” Everyone’s Talking About?
A “dark matter storm” is the name given by scientists to a possible “cloud” of dark matter present in stellar streams. Stellar streams, on the other hand, are a gathering of related stars that were once part of a different dwarf galaxy or globular cluster but are now torn apart and stretched out by gravity.
Every galaxy has these stellar streams, and our Milky Way galaxy is no exception. One such stream that scientists observed is the S1 Stream. Scientists believe that the S1 stream was creating in a massive cosmic event wherein our galaxy collided with another, smaller galaxy.
Because the S1 stream flows directly through the path of our solar system’s sun, scientists are predicting that the dark matter they carry will also pass through, and because dark matter is so diffused, it could also engulf the Earth.
In fact, some scientists believe that the dark matter storm is passing though us AS WE SPEAK!
Should We Be Worried?
Given what little we know of dark matter, it can be a little alarming when scientists announce that a “dark matter storm” is headed our way. But because we know so little about it, and considering that the amount of dark matter in the S1 stellar stream is relatively small, scientists believe it will have no discernible effect on the planet, or on the solar system in general.
However, scientists are excited because this is one of the rare instances where we are crossing paths with an abundant amount of particles that may or may not exist. At the moment, physicists around the world are currently plotting out ways to verify, calculate, detect, and study a particle that they’re not 100% sure exists.
So, we can all relax, for now. Until we figure out what dark matter is (or if it even exists), it’s safe to say that we’ll live to see the next round of superhero films in the movie house.