Dark Matter

(Nasa, 2023)

History:

At the beginning of the 1990s, the belief about the universe's fate was relatively straightforward. It was thought that the universe, driven by gravity's pull, would eventually slow down its expansion. Perhaps it had just enough energy density to halt its expansion and breakdown or maybe it would expand forever but at a slower rate. The certainty was that gravity would act as the cosmic conductor, forcing the universe’s expansion to slow down. However, in 1998, the Hubble Space Telescope (HST) (Nasa, 2023) unveiled observations that would change this cosmic narrative. By observing distant supernova, it was shown that the expansion of the universe was not slowing down, it was accelerating. This strange phenomenon was caused by a type of energy that was later called dark energy.

Is dark matter important?

By analyzing many cosmological observations, scientists have put together a model describing what does the universe contain: approximately 68% dark energy, 27% dark matter, and a mere 5% normal matter (Nasa, 2023). So yes, it is a pretty big deal.

What is dark matter?

It's Dark (bet you didn’t guess that one): Dark matter neither emits or reflects light, making it invisible. It does not manifest as stars or planets. (Nasa, 2023)

Not Baryonic Matter (the matter that we know): It's not composed of baryonic matter. We can rule out dark matter as dark clouds of these ordinary particles, as they would absorb radiation passing through them, leaving a detectable mark.

It is not antimatter, nor does it contain any.

What is being done to uncover the universe’s greatest mystery?

WIMPs (not in the literal sense) and Axions: One leading hypothesis suggests that dark matter consists of Weakly Interacting Massive Particles (WIMPs) or ultralight particles called axions. These hypothetical particles interact weakly with ordinary matter, making them almost undetectable targets for future experiments. (Nasa, 2023)

Underground Laboratories: Researchers have constructed underground laboratories to shield sensitive detectors from cosmic rays. These facilities aim to capture rare interactions between dark matter particles and nuclei, shedding light on this enigmatic substance. (Nasa, 2023)

Colliders and Telescopes:

Particle accelerators and observatories continue to search for indirect evidence of dark matter particles through high-energy collisions and astrophysical observations. (Nasa, 2023)

As the search for dark matter continues, the cosmic mystery keeps the scientific community guessing and trying to figure out what it is. While we’ve underlined what dark matter isn't, the road to unveil its true nature is long. It leaves one to wonder how much uncharted territory in this field is left to be discovered.

Bibliography

Nasa. (2023, October 16). Dark Energy, Dark Matter. Nasa.