A gold mine in South Dakota once produced millions of ounces of precious metal.
asserted
mine → produce → metal
Today, the same site is being used to study some of the biggest mysteries in the universe.
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site → use → universe
The Homestake Gold Mine in Lead, South Dakota, operated for 125 years before it closed in 2001.
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it → operate → 2001
According to Sanford lab, during its lifetime, the mine produced about 41 million ounces of gold and 9 million ounces of silver, making it the largest and deepest gold mine in North America at the time.
uncertain
it → accord → time
The mine later took on a completely different when in 2006, businessman T Denny Sanford pledged $70 million to help revive plans for an underground research laboratory.
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Sanford → take → laboratory
Barrick Gold Corporation, which owned the Homestake property, donated land, while South Dakota committed more than $40 million to the project.
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Dakota → own → project
The efforts led to the creation of the Deep Underground Science and Engineering Laboratory, now known as the Sanford Underground Research Facility (SURF), in 2007.
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efforts → lead → 2007
Today, SURF is the deepest underground laboratory in the United States, reaching 4,850 feet below the surface.
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SURF → reach → surface
Scientists from dozens of countries work there to study questions about the universe and Earth.
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Scientists → work → universe
How mine became lab
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mine → become → ?
The idea of using the mine for science was not new at that time.
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idea → use → time
Research had already begun there decades before mining even ended.
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mining → begin → ?
In the mid-1960s, physicist Raymond Davis Jr built the Brookhaven Solar Neutrino Experiment deep inside the Homestake Mine.
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Jr → build → Mine
His experiment used a 100,000-gallon tank filled with perchloroethylene, a chlorine-containing dry-cleaning fluid, to detect neutrinos coming from the Sun.
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experiment → use → Sun
He later recieved the Nobel Prize in Physics in 2022 for detecting cosmic neutrinos.
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He → recieve → neutrinos
Neutrinos are extremely difficult to detect because they interact very weakly with matter.
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they → detect → matter
The experiment therefore needed protection from unwanted signals that could interfere with the measurements.
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that → need → measurements
The mine's great depth provided an environment suited to this type of research.
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depth → provide → research
Davis continued his work for nearly three decades in an underground area that later became known as the Davis Cavern.
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that → continue → Cavern
Scientists then began pushing for the site to be converted into a permanent underground research laboratory.
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site → begin → laboratory
Search for dark matter
Once the site was developed as a modern research facility, scientists began installing major physics experiments deep underground.
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scientists → search → experiments
It was installed on the 4,850-foot level and was designed to search for dark matter.
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It → instal → matter
Dark matter is a mysterious form of matter that scientists believe exists, but it has not been directly detected.
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it → believe → matter
It does not interact with light in the way ordinary matter does, making it difficult to study.
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it → interact → way
In October 2013, after an initial 80-day run, LUX was found to be the most sensitive dark matter detector in the world.
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LUX → find → world
Further analysis confirmed its sensitivity in 2016, the same year the experiment was decommissioned.
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experiment → confirm → 2016
LUX was later followed by a second-generation experiment, LUX-ZEPLIN, or LZ.
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LUX → follow → experiment
It began operating in 2021 and was announced as the world's most sensitive dark matter detector when its first results were released on July 7, 2022.
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results → begin → July
The underground setting remains central to these experiments.
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setting → remain → experiments
SURF's deep location allows scientists to conduct highly sensitive searches in an environment protected by thousands of feet of rock.
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scientists → allow → rock
Looking for rare radioactive decay
Another major experiment at SURF has been searching for something even more elusive.
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experiment → look → something
The Majorana Demonstrator operating from 2015 to 2021, was used to search for neutrinoless double-beta decay, a rare type of radioactive decay that has never been observed.
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that → operate → decay
Finding this decay could help explain why matter exists in our Universe.
uncertain
matter → find → Universe
The experiment's final results, published in early 2023, showed that the techniques used by the collaboration could be applied to a much larger experiment.
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techniques → publish → experiment
The collaboration is now working with another germanium experiment to develop the Large Enriched Ge Experiment for Neutrinoless ββ Decay, or LEGEND.
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collaboration → work → Decay
The same year Davis received the Nobel Prize, the Homestake Mine closed.
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Mine → receive → Prize
Research beyond physics
The extreme conditions underground have also opened the door to research outside particle physics.
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conditions → open → physics
Scientists have studied microbial lifeforms living in the underground environment.
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Scientists → study → environment
Some of this research has been linked to questions about medicines, biofuels and carbon sequestration.
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Some → link → medicines
SURF says research carried out there has also helped inform the search for life on Mars.
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research → say → Mars
…and 5 more, not listed.
The Aporia
