Is Dark Matter Real? Here’s What We Know About It

August 15, 2019 • Shannon Flynn

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The
universe — stars, planets, galaxies, the sun, etc. — is made up of protons,
neutrons and electrons, all bundled together into atoms called baryonic matter.
Less than 5% of the mass of the
universe
is
baryonic matter. The rest is dark energy and dark matter.

A New Discovery

Stars
are held into orbit by gravity, flying along circular paths. According to Isaac
Newton, the force propelling a star in a circular path should equal the force
of gravity on the star. Otherwise, the star would fly off into space or drop to
the center of the galaxy.

In
1932, Jan Oort, a Dutch astronomer, was the first to discover
something amiss
with the orbital speed of stars. He claimed they moved too quickly
compared to the mass of the Milky Way. Later, using Newton’s equation, Vera
Rubin and Kent Ford discovered Oort was right — stars at the edges of galaxies
were traveling faster than predicted.

It’s
commonly accepted among the scientific community that gravity will slow the
expansion of the universe over time. There were two theories — the universe
would either expand forever or eventually stop its expansion and recollapse. In
1998, however, the Hubble Space Telescope’s observations of distant supernovae proved the
expansion of the universe
has been accelerating, not slowing down.

Such
discrepancies require explanation. Several theories have been developed over
time, including an issue with Einstein’s theory of gravity and a strange
energy-fluid that supposedly fills space. The solution to the problem, still
not understood, is dark matter.

What is Dark Matter?

Scientists
don’t know a lot about dark matter, because it’s never been observed or proven.
It’s estimated roughly 25% of the universe is composed of dark matter. Yet it
doesn’t interact with baryonic matter and is entirely invisible to light and
electromagnetic radiation. While still a hypothesis, experts believe it must
exist due to its gravitational effects on galaxies.

Dark
matter has no electromagnetic charge, as far as we know. It doesn’t even need
to consist of atoms, as it can be any material that
interacts with gravity
in the same way matter does, though it’s made up of something else
entirely. Experts believe dark matter is likely made of exotic particles like
axions or WIMPS (Weakly Interacting Massive Particles).

Dark
matter impacts the stars in our galaxy, as well as the motion of galaxies in
clusters. The most convincing sign of dark matter is our own existence. Experts
say that because dark matter carries five times the mass of ordinary matter, it
is critical to the evolution of the universe, including the emergence of stars,
planets and life.

Is Dark Matter Real?

Dark
matter exists — we just don’t know a lot about it. So far, no one understands
how dark matter appeared or how it affects the universe. Scientists believe
that once researched further, we’ll be able to discover the underlying
fundamentals.

Some
believe that to understand dark matter, we have to modify our theories of
gravity substantially. The idea states there are multiple forms of gravity,
including large-scale gravity that governs galaxies different from our own.

Many
scientific groups are working to generate dark matter particles in the lab for
further study. Others are attempting to design
next-generation equipment
able to detect the mysterious matter.

The
race is on across the scientific community to learn more about this natural
phenomenon — including how it works and what it means for our universe. While
still a hypothesis, the existence of dark matter is well-documented and
accepted. The next step, already in the works, is to discover how we can use
specialized equipment to observe this type of matter.



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