Scientists see 'rarest event ever recorded' in search for dark matter
The team caught a glimpse of a process that takes 18,000,000,000,000,000,000,000 years.
- In Italy, a team of scientists is using a highly sophisticated detector to hunt for dark matter.
- The team observed an ultra-rare particle interaction that reveals the half-life of a xenon-124 atom to be 18 sextillion years.
- The half-life of a process is how long it takes for half of the radioactive nuclei present in a sample to decay.
Scientists have observed an extremely rare particle physics event using a detector that's hunting for dark matter, the mysterious material that physicists have yet to observe.
In a paper published in the journal Nature, researchers with the XENON Collaboration said they'd observed the radioactive decay of a substance called xenon-124, an isotope of the element xenon — a colorless and odorless noble gas found in tiny amounts in the atmosphere. The event — a "two-neutrino double electron capture" — has eluded scientists for decades.
It happens when "two protons in a nucleus are simultaneously converted into neutrons by the absorption of two electrons from one of the atomic shells and the emission of two electron neutrinos." After this occurs, the event shoots out a predictable cascade of X-rays and Auger electrons that scientists look for using an ultra-sensitive detector, buried about 5,000 feet beneath Italy's Gran Sasso mountain where it's shielded from cosmic rays.
"We have shown that we can observe the rarest events ever recorded," Ethan Brown, a professor of physics at Rensselaer Polytechnic Institute and co-author of the study, told Newsweek. "The key finding is that an isotope formerly thought to be completely stable has now been shown to decay on an unimaginably long timescale."
How long is that timescale? The team estimated that xenon-124's half-life is about 18 sextillion years — or 18,000,000,000,000,000,000,000 years — which is than one trillion times the age of our universe, according to the team. It's the slowest process ever measured directly, the team wrote in a statement.
"It's an amazing to have witnessed this process, and it says that our detector can measure the rarest thing ever recorded," Brown told The Independent.
"We designed the XENON1T experiment to look for dark matter, a new kind of matter that makes up 85 percent of the mass of the universe, but interacts so rarely that it's never been observed," Brown said. "This experiment is so sensitive to very rare events that we can make all kinds of other rare physics measurements. One of those is this decay of xenon-124. Although our primary goal was always the discovery of dark matter, we knew there was a good chance we could see this rare decay, so we set out to do so."
To get that good chance, the team had to expose their detector to a huge amount of xenon atoms by stocking it with 3.2 tons worth of liquid xenon.
"XENON1T is a giant vat of liquid xenon surrounded by light sensors," Brown said. "When dark matter collides in the xenon, or when a radioactive decay occurs inside, we get a tiny flash of light and a little bunch of charge out of the xenon. We measure these with the light sensors and reconstruct everything we can about the original event that caused the light and charge."
Although the team didn't observe dark matter — which is the primary purpose of the detector — the recent observations could help scientists learn more about neutrinos, one of the least understood fundamental particles in the universe.
"It proves that this XENON detector technology we use for dark matter is much more versatile," graduate student Christian Wittweg, Ph.D student at the University of Münster in Germany, told Gizmodo. "We get all these cool analyses... for free after having built an experiment sensitive enough to hunt for dark matter."
The team plans to use its newer XENONnT detector to continue hunting for dark matter, the elusive material that's estimated to comprise about 26.8 percent of all the content in the universe.
- This is the slowest radioactive decay ever spotted | Science News ›
- Two-component dark matter and a massless neutrino in a new B− L ... ›
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Proof of a dramatic shift in US cable news viewing preferences - or not? The devil is in the map's legend
- Map details dramatic shift from CNN to Fox News over 10-year period
- But does it show the triumph of 'fake news' or rather its defeat?
- A closer look at the map's legend allows for more complex analyses
Dramatic and misleading
Image: Reddit / SICResearch
The situation today: CNN pushed back to the edges of the country.
Over the course of no more than a decade, America has radically switched favourites when it comes to cable news networks. As this sequence of maps showing TMAs (Television Market Areas) suggests, CNN is out, Fox News is in.
The maps are certainly dramatic, but also a bit misleading. They nevertheless provide some insight into the state of journalism and the public's attitudes towards the press in the US. Let's zoom in.
- It's 2008, on the eve of the Obama Era. CNN (blue) dominates the cable news landscape across America. Fox News (red) is an upstart (°1996) with a few regional bastions in the south.
- By 2010, Fox News has broken out of its southern heartland, colonising markets in the Midwest and Northwest – and even northern Maine and southern Alaska.
- Two years later, Fox News has lost those two outliers, but has filled up in the middle: it now boasts two large, contiguous blocks in the southeast and northwest, almost touching.
- In 2014, Fox News seems past its prime. The northwestern block has shrunk, the southeastern one has fragmented.
- Energised by Trump's 2016 presidential campaign, Fox News is back with a vengeance. Not only have Maine and Alaska gone from entirely blue to entirely red, so has most of the rest of the US. Fox News has plugged the Nebraska Gap: it's no longer possible to walk from coast to coast across CNN territory.
- By 2018, the fortunes from a decade earlier have almost reversed. Fox News rules the roost. CNN clings on to the Pacific Coast, New Mexico, Minnesota and parts of the Northeast – plus a smattering of metropolitan areas in the South and Midwest.
Image: Reddit / SICResearch
This sequence of maps, showing America turning from blue to red, elicited strong reactions on the Reddit forum where it was published last week. For some, the takeover by Fox News illustrates the demise of all that's good and fair about news journalism:
- "The end is near"
- "The idiocracy grows"
- "(It's) like a spreading disease"
- "One of the more frightening maps I've seen"
- "LOL that's what happens when you're fake news!"
- "CNN went down the toilet on quality"
- "A Minecraft YouTuber could beat CNN's numbers"
- "CNN has become more like a high-school production of a news show"
Not a few find fault with both channels, even if not always to the same degree:
- "That anybody considers either of those networks good news sources is troubling"
- "Both leave you understanding less rather than more"
- "This is what happens when you spout bullsh-- for two years straight. People find an alternative - even if it's just different bullsh--"
- "CNN is sh-- but it's nowhere close to the outright bullsh-- and baseless propaganda Fox News spews"
"Old people learning to Google"
Image: Google Trends
CNN vs. Fox News search terms (200!-2018)
But what do the maps actually show? Created by SICResearch, they do show a huge evolution, but not of both cable news networks' audience size (i.e. Nielsen ratings). The dramatic shift is one in Google search trends. In other words, it shows how often people type in CNN or Fox News in a search window. And that does not necessarily reflect the relative popularity of both networks. As some commenters suggest:
- "I can't remember the last time that I've searched for a news channel on Google. Is it really that difficult for people to type 'cnn.com'?"
- "More than anything else, these maps show smart phone proliferation (among older people) more than anything else"
- "This is a map of how old people and rural areas have learned to use Google in the last decade"
- "This is basically a map of people who don't understand how the internet works, and it's no surprise that it leans conservative"
A visual image as strong as this map sequence looks designed to elicit a vehement response – and its lack of context offers viewers little new information to challenge their preconceptions. Like the news itself, cartography pretends to be objective, but always has an agenda of its own, even if just by the selection of its topics.
The trick is not to despair of maps (or news) but to get a good sense of the parameters that are in play. And, as is often the case (with both maps and news), what's left out is at least as significant as what's actually shown.
One important point: while Fox News is the sole major purveyor of news and opinion with a conservative/right-wing slant, CNN has more competition in the center/left part of the spectrum, notably from MSNBC.
Another: the average age of cable news networks – whether CNN or Fox News – is in the mid-60s. As a result of a shift in generational habits, tv viewing is down across the board. Younger people are more comfortable with a 'cafeteria' approach to their news menu, selecting alternative and online sources for their information.
CNN, Fox and MSNBC
Image: Google Trends
CNN vs. Fox (without the 'News'; may include searches for actual foxes). See MSNBC (in yellow) for comparison
For the record, here are the Nielsen ratings for average daily viewer total for the three main cable news networks, for 2018 (compared to 2017):
- Fox News: 1,425,000 (-5%)
- MSNBC: 994,000 (+12%)
- CNN: 706,000 (-9%)
And according to this recent overview, the top 50 of the most popular websites in the US includes cnn.com in 28th place, and foxnews.com in... 27th place.The top 5, in descending order, consists of google.com, youtube.com, facebook.com, amazon.com and yahoo.com – the latter being the highest-placed website in the News and Media category.(Source: SimilarWeb)
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