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A 'Hubble Crisis'? New Measurement Confirms Universe is Expanding Too Fast for Current Models

3 months 2 weeks ago
"The universe is expanding faster than predicted by theoretical models," writes Phys.org, "and faster than can be explained by our current understanding of physics." There's now been new confirmation of this (published in The Astrophysical Journal Letters) by a team led by Dan Scolnic, an associate professor of physics at Duke University. And this means the so-called Hubble tension "now turns into a crisis," said Dan Scolnic, who led the research team... This is saying, to some respect, that our model of cosmology might be broken." Measuring the universe requires a cosmic ladder, which is a succession of methods used to measure the distances to celestial objects, with each method, or "rung," relying on the previous for calibration. The ladder used by Scolnic was created by a separate team using data from the Dark Energy Spectroscopic Instrument (DESI), which is observing more than 100,000 galaxies every night from its vantage point at the Kitt Peak National Observatory. Scolnic recognized that this ladder could be anchored closer to Earth with a more precise distance to the Coma Cluster, one of the galaxy clusters nearest to us. "The DESI collaboration did the really hard part, their ladder was missing the first rung," said Scolnic. "I knew how to get it, and I knew that that would give us one of the most precise measurements of the Hubble constant we could get, so when their paper came out, I dropped absolutely everything and worked on this non-stop." To get a precise distance to the Coma cluster, Scolnic and his collaborators used the light curves from 12 Type Ia supernovae within the cluster. Just like candles lighting a dark path, Type Ia supernovae have a predictable luminosity that correlates to their distance, making them reliable objects for distance calculations. The team arrived at a distance of about 320 million light-years, nearly in the center of the range of distances reported across 40 years of previous studies — a reassuring sign of its accuracy. "This measurement isn't biased by how we think the Hubble tension story will end," said Scolnic. "This cluster is in our backyard, it has been measured long before anyone knew how important it was going to be." The results? "It matches the universe's expansion rate as other teams have recently measured it," writes Phys.org, "but not as our current understanding of physics predicts it. The longstanding question is: is the flaw in the measurements or in the models? Scolnic's team's new results add tremendous support to the emerging picture that the root of the Hubble tension lies in the models..." And the article closes with this quote from Scolnic: "Ultimately, even though we're swapping out so many of the pieces, we all still get a very similar number. So, for me, this is as good of a confirmation as it's ever gotten. We're at a point where we're pressing really hard against the models we've been using for two and a half decades, and we're seeing that things aren't matching up," said Scolnic. "This may be reshaping how we think about the universe, and it's exciting! There are still surprises left in cosmology, and who knows what discoveries will come next?"

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EditorDavid

After PFAS Contamination on English Channel Island, Government Panel Recommends Bloodletting for Those Affected

3 months 2 weeks ago
Jersey is an island in the English channel, "a self-governing British Crown Dependency near the coast of northwest France," according to Wikipedia — population: 103,267. But now some residents of Jersey "have been recommended bloodletting to reduce high concentrations of 'forever chemicals' in their blood," reports the Guardian, "after tests showed some islanders have levels that can lead to health problems." Private drinking water supplies in Jersey were polluted by the use of firefighting foams containing PFAS (per- and polyfluoroalkyl substances) at the island's airport, which were manufactured by the U.S. multinational 3M. .. Bloodletting draws blood from a vein in measured amounts. It is safe and the body replenishes the blood naturally, but it must be repeated until clean... In response to the blood results, the government established an independent PFAS scientific advisory panel to advise public policy. The panel's first report recommended that the government should look at offering bloodletting to affected residents. "Studies show that bloodletting is an effective way to lower levels of PFAS in blood," said Ian Cousins, one of the panel members, though he added that there were no guarantees the process would prevent or cure diseases associated with the chemicals. The therapy costs about £100,000 upfront and then as much as £200,000 a year to treat 50 people. The panel is also considering the benefit of the drug cholestyramine, which a study has shown reduces PFAS in blood more quickly and cheaply, albeit with possible side effects. The government says it plans to launch a clinical service by early 2025. Contamination persisted on the island for decades. "We know they started to use 3M's firefighting foam in the 1960s and then ramped up in the 1990s in weekly fire training exercises, after which foam started to appear in nearby streams," said Jeremy Snowdon, a former Jersey airport engineer who drank contaminated water for years. He has measured elevated levels of PFAS in his own blood and has high cholesterol. The article includes this quote from one of the 88 residents of the polluted area found to have high levels of PFAS after blood testing. "I just want this out of my body. I don't want to end up with bladder cancer."

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EditorDavid