Back in 1933, Caltech astronomer and astrophysicist Fritz Zwicky was observing the Coma cluster, a large group of galaxies located some 321 million light years away in the Coma Berenices constellation.
He noticed the speed of the galaxies rotating within the cluster was much faster than the quantity of its mass he had calculated.
According to Isaac Newton’s theory of gravity, Zwicky thought this difference should have caused the galaxies to spin-off from the cluster.
So, he then figured that for all his observational information to add up with Newton’s theory, along with matter that could be seen, the cluster also had to contain a good amount of some kind of material that couldn’t be seen.
He called this invisible substance “dark matter.”
In the years since Fritz Zwicky’s finding, researchers have been trying feverishly to make an actual detection of dark matter.
Most are quite sure of its existence because of the gravitation influence it has on various cosmic objects, such as what Zwicky found with the Coma cluster in 1933.
The way light bends as it makes it way through space is another clue scientists say also points to dark matter.
NASA says this mystery material makes up roughly 27 percent of the known or observable universe. Dark energy, the force said to be responsible for the expansion of the universe, is thought to make up nearly 68 percent while normal matter, the things we can see and touch, makes up the remaining 5 percent.
Now, some 83 years after Zwicky’s discovery, a group of scientists say that despite searching for twenty months, with what is said to be the world’s most sensitive dark matter detector, they still have not been able to directly detect even a trace of the mysterious stuff .
Scientists with the Large Underground Xenon (LUX) dark matter experiment, presented findings of their experiment’s final run at the Identification of Dark Matter 2016 conference (IDM 2016), held this past week in Sheffield, England.
The dark matter experiment was conducted at the Sanford Underground Research Facility, located beneath a little more than 1.6 km of earth and rock in the Black Hills of South Dakota.
The scientific consortium found that the sensitivity of their detector, a 370 kg liquid xenon time-projection chamber, was four times greater than they expected. They contend that if any dark matter particles had actually interacted with their device – it would have pointed them out.
To search for dark matter the scientists say their experiment was set-up to look for WIMPS, otherwise known as Weakly Interacting Massive Particles, which is where they think they’ll be able to find dark matter.
They theorize every second, billions of these WIMP particles are actually passing through our bodies, everything that surrounds us and through the Earth itself.
According to the scientists, we don’t notice this continual bombardment because the interaction of these WIMP particles with ordinary matter is quite weak.
Over its last 20 month run – October 2014 through May 2016 – the researchers say their experiment gathered and then analyzed nearly 500 terabytes or 500,000 gigabytes worth of data.
While they were unable to actually detect any dark matter, the LUX scientists say their experiment did eliminate a good number of possible models where the WIMP particles might be found.
The LUX team says their research and findings will also help future investigators in their hunt for dark matter.
The LUX-ZEPLIN (LZ) experiment, which is set to replace LUX at the Sanford Underground Research Facility will continue the search some time in 2020.