Scientists Were Hunting for Dark Matter...and Then This Happened

  • Published on:  9/6/2019
  • These scientists discovered the longest half-life ever recorded.
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    In April 2019, the Xenon1T detector in Italy aimed to detect dark matter with liquid xenon. While they failed to succeed, the team did discover the longest half-life ever recorded, which is extraordinarily rare.

    The experiment consisted of an enormous tank filled mostly with xenon cooled to -96 degrees Celsius, and while the vat contained 3.2 metric tons of liquid xenon, the experiment had a targeted exposure rate of 1 metric ton per year, hence the 1T in the name.

    The scientists were trying to expose the xenon to dark matter, or most specifically Weekly Interacting Massive Particles (WIMPs), which are thought to be heavy, slow-moving particles. But the particles are just hypothetical.

    The experimental hope was that while watching a gigantic tank of xenon very closely, a WIMP would collide with an atom and transfer some of that energy to the atom’s nucleus. In turn, that would excite other xenon atoms, ultimately leading to the release of faint signals of ultraviolet light and trace amounts of electrical charge which could be detected by sensors at the top and bottom of the tank.

    And after collecting data from 2016 to December 2018, scientists didn’t detect any dark matter, not a single hint of a WIMP. Instead, they discovered something else pretty monumental: a record-setting half-life.

    Learn more about the Xenon1T detector, the experiment and the unexpected result in this episode of Elements.


    Read More:
    Dark matter detector reveals material with longest half-life ever – 18 sextillion years
    "According to this study, the half-life of xenon 124 is a barely-comprehensible 18 sextillion years, or an 18 followed by 21 zeroes. For comparison's sake, that's more than a trillion times longer than the age of the universe itself, which is a mere 13.8 billion years young."

    Dark Matter
    "Dark matter is stuff in space that has gravity, but it is unlike anything scientists have ever seen before. Together, dark matter and dark energy make up 95% of the universe. That only leaves a small 5% for all the matter and energy we know and understand."

    Dark Matter Search Results from a One Ton-Year Exposure of XENON1T
    "XENON1T utilizes a liquid xenon time projection chamber with a fiducial mass of (1.30±0.01) ton, resulting in a 1.0 ton yr exposure."


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