Astronomers found that galaxies were rotating too fast to withstand forces pulling them apart. Something had to account for the missing gravitational effects by a factor of 10. At first the search was focused on finding a cosmic bodies that could not be seen from Earth such as brown dwarf stars and neutron stars. but once the numbers were crunched and powerful telescopes searched into far reaches of the electromagnetic spectrum, these candidates were insufficient to account for the missing mass. Dubbed "dark matter", scientists reformed their hypotheses from the incredibly large to incredibly small. Vast numbers of subatomic particles that interact only very rarely with ordinary matter are thought to be whizzing around in interstellar space, accounting for the missing mass of the universe that holds it together. Scientist calculate that dark matters is 85% of the mass of the universe. That is a lot of matter scientists have been searching for during the last two decades without success.
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| Lux-Zepplin WIMP detector |
The Earth is constantly bombarded by cosmic energy making the search for such an elusive, and possibly non-existent particle extremely difficult--background radiation drowns out detection. Neutrinos are also small and electrically neutral, which make them able to penetrate meters of crust. So the searchers took their WIMP detectors deep underground. The Gran Sasso National Laboratory is in a tunnel 1.4km below a stone mountain, which makes it one of the least radioactive places on Earth. Researchers have further shielded their sensitive detectors in spheres of xenon gas surrounded by purified water to isolate their instruments.
Dark natter detectors are reaching the limits of available technology, yet no one has found a WIMP. The Gran Sasso detector known as XENONnT and the other, Lux-Zeplin, [photo credit: UK Guardian] constructed in an old South Dakota gold mine, are filled with several tonnes of xenon – much more than has been put in any previous device that should increase chances of a nucleus being struck by a wimp. Both will be run for a period of years to improve the possibility of detection. Such a collision would produce an infinitesimal spark of light energy that can be observed. If the two teams fail to find WIMPS. scientists will have one final chance to use current technology to find them by joining forces to create one final super detector. Making detectors even more sensitive would be self-defeating as they would be overwhelmed by trillions of neutrinos that penetrate the Earth every second.
It may be that dark matter is undetectable in this universe, or more troubling, modern physics' understanding of the cosmos is incorrect. Nevertheless, the search for the ghost particles continues because as one researcher explained, "It is quite simple. There would no Earth or humans if there had not been dark matter. Without these particles' considerable mass, galaxies would not have been able to form in the early universe." The search may be akin to looking for lost keys under a lamppost, or finding the Holy Grail. The search for WIMPS is perhaps a matter of faith.
For my thoughts are not your thoughts, neither are your ways my ways, saith the Lord. [Isaiah 55:8].