Dark Matter Searches Continue to Fail

The more precise the detectors,
the less the evidence for the
mysterious unknown stuff

 

Is it past time to cease the fruitless quest for dark matter? Some think the project stems from a desire to maintain a popular theoretical framework. At what point does non-detection speak to reality itself?

Dark matter could be hiding inside strange failed stars (30 Aug 2024, New Scientist). Dark matter “could” also “be hiding” in unicorn horns. It could be hiding in leprechauns, or in brown dwarfs. Without evidence, such perhapsimaybecouldness is not science.

85% of the matter in the universe is missing. But we’re getting closer to finding it (26 Aug 2024, The Conversation). Theresa Fruth demonstrates how to keep hope alive while admitting complete failure. She thinks that narrowing the place where the snipe could be hiding represents progress.

• We have not yet found the elusive particles we believe dark matter consists of, but we have set the tightest limits yet on their properties. We have also shown our detector is working as expected – and should produce even better results in the future….
• So what is this dark matter made of? We currently don’t know of any kind of particle that could explain these astronomical observations.
• Our latest results show no signs of dark matter. However, they let us rule out a lot of possibilities.

Pioneering research suggests nature of dark matter is more elusive than ever (28 Aug 2024, Univ of Bristol). It’s in! The latest result from the LUX-ZEPLIN Dark Matter Experiment (LZ) in South Dakota designed to hunt for Weakly Interacting Massive Particles (WIMPs), one of the prime candidates for dark matter. Alas; the refrain is the same.

LZ found no evidence of WIMPs above a mass of 9 GeV/c², where 1 GeV/c² roughly corresponds to the mass of a hydrogen atom.

The experiment now needs to run for up to 1,000 days to realise its full sensitivity. This initial result is just a fraction of that exposure, which validates the decade-long design and construction effort.

If you were someone paying for this project, would you agree that non-detection validates the decade-long design and construction effort? The believers in dark matter took lessons from the OOL people:

LZ Experiment Sets New Record in Search for Dark Matter (26 Aug 2024, Berkeley Lab). Here’s another admission that the extremely sensitive LZ experiment failed. But failure is not an option. The money must be spent!

Researchers have only scratched the surface of what LZ can do. With the detector’s exceptional sensitivity and their advanced analysis techniques, the collaboration is primed to discover dark matter if it exists within the experiment’s reach and to explore other rare physics phenomena.

Another blow for dark matter as biggest hunt yet finds nothing (26 Aug 2024, New Scientist). Reporter Leah Crane is honest about the emotional toll of continued non-detection. “The hunt for particles of dark matter has been stymied once again, with physicists placing constraints on this mysterious substance that are 5 times tighter than the previous best.” The proponents are determined to find the magical fish!

“It’s as if we’ve been told there’s some magical fish that lives in the ocean and we have no idea where it is,” says [Charnkaur] Ghag [of University College London]. “We get into the ocean, swim around, get out, get a snorkel, swim around, still don’t find it, get a submarine.” If the magical fish is a WIMP, researchers have now explored about 75 per cent of the ocean without finding it, he says.

Primordial black holes are too scarce to explain dark matter (19 Aug 2024, Nature News). Those looking for dark matter in primordial black holes have good news and bad news.

A decades-long survey of a nearby galaxy has detected signals consistent with ancient black holes that could explain dark matter — but the objects would have to be at least ten times more abundant to support the theory.

Because of the philosophical problem of underdetermination of theory by data (17 April 2020), this cannot count as good news in any sense. There are other explanations for the observations that are merely “consistent with” the hypothesis of ancient black holes.

A Camera Trap for the Invisible (29 July 2024, Duke University Research Blog). Researchers at the Large Hadron Collider (LHC) might be able to discern the tracks of dark matter particles. The job, however, is harder than finding a needle in a haystack. “It sounds fantastical,” admits reporter Robin Smith. The diligence of Ashutosh Kotwal in this project is admirable, provided he keeps getting paid looking for something “whose nature remains a mystery.”

Astronomers observe the effect of dark matter on the evolution of the galaxies (21 Feb 2024, Canary Island Institute of Astrophysics). Again, because of underdetermination of theory by data, many other explanations might be consistent with the observed indirect effects on galaxies.

Dark matter comprises around 85% of all the matter in the Universe. Although ordinary matter absorbs, reflects and emits light, dark matter cannot be seen directly, which makes its detection difficult. Its existence is inferred from its gravitational effects on visible matter, the material which forms stars, planets, and the other objects in the cosmos.

Dark matter wizards toss around percentages as if they are precise. Depending on the source, the percentage of theoretical dark matter varies all over the map, from 20% to 95%. Often it gets mixed in with dark energy, another mysterious notion that is supposed to be even more prevalent than dark matter. The resulting dogmatic statements sound like the ratio between leprechauns and unicorns: interesting only to the naive.

What is Dark Energy? Inside our accelerating, expanding Universe (5 Feb 2024, NASA). Here is official state dogma to the gullible.

Some 13.8 billion years ago, the universe began with a rapid expansion we call the big bang. After this initial expansion, which lasted a fraction of a second, gravity started to slow the universe down. But the cosmos wouldn’t stay this way. Nine billion years after the universe began, its expansion started to speed up, driven by an unknown force that scientists have named dark energy.

But what exactly is dark energy?

The short answer is: We don’t know. But we do know that it exists, it’s making the universe expand at an accelerating rate, and approximately 68.3 to 70% of the universe is dark energy.

Wow; they know the unknown to 3 significant figures! Time to reread Brett Miller’s cartoon above.

China’s new dark-matter lab is biggest and deepest yet (22 Jan 2024, Nature News). “The laboratory is scaling up its equipment to hunt for dark matter,” this item reported months ago. Find something else worthwhile to do while waiting for their findings, if any.

Trouble in Theory Fantasyland

Dark Matter–Star ‘Conspiracy’ Debunked by Astronomers (21 Aug 2024, Newsweek). A common explanation for how stars interact may have nothing to do with dark matter.

An astronomical “conspiracy” about how stars and dark matter interact has been disproved by scientists.

This debunked theory was originally suggested to explain why matter appears to decrease in density at the same rate across the center and the edges of galaxies, which confused scientists, as galaxies around the universe vary significantly in shape, size and age.

Dark matter had been theorized as an explanation for this phenomenon, but now, according to a paper published on August 10 in the journal Monthly Notices of the Royal Astronomical Society, this may not be the true reason.

Now “researchers suggest that these similarities in density may not be due to how the galaxies themselves are built, but are instead a result of how we measure them.” Is dark matter theory a figment of measurement error?

Study: Stars travel more slowly at Milky Way’s edge (26 Jan 2024, MIT News). Jennifer Chu reports, “The findings suggest our galaxy’s core may contain less dark matter than previously estimated.” I never estimated dark matter for our galaxy’s core. Did you? If not, congratulations. You were not proved wrong.

MIT physicists have debunked a primary measurement that led to the belief in dark matter. In the 1970s, Vera Rubin measured rotation curves of galaxies that implied more mass at the outer edges than could be seen in visible light. Were her measurements off?

The team translated the new rotation curve into a distribution of dark matter that could explain the outer stars’ slow-down, and found the resulting map produced a lighter galactic core than expected. That is, the center of the Milky Way may be less dense, with less dark matter, than scientists have thought.

“This puts this result in tension with other measurements,” Necib says. “There is something fishy going on somewhere, and it’s really exciting to figure out where that is, to really have a coherent picture of the Milky Way.”

Follow that fish odor till it gets stronger. It might lead to the remnants of a dead, decaying theory. That, indeed, might be really exciting. Think of how sweet fresh air will smell when the dead fish is tossed.

There are prominent creationists who still believe in dark matter. I can understand their reticence to doubt it. Maybe they feel it is the most likely explanation for galaxy rotation curves. Maybe they feel that challenging Newtonian physics at the galactic scale is a bridge too far. Maybe they dislike unnecessary criticisms of consensus models that make creationists look ignorant.* My challenge to them is, “Show me the particle.” Would you believe in ghosts just because consensus theories require their presence to explain certain mysterious effects?

*For a similar situation in biology, see this editorial.

Consensus is not science. The consensus has been dragging the public through their dark matter search for decades now, with nothing to show for it. How much more time do they get? How much more money? What is the expiration date?

I think it is philosophically more honest to just state that there are aspects of the universe we do not understand rather than to go on a decades-long snipe hunt that the consensus promises will be successful if we keep spending millions of dollars on it. Look at the cartoon above again. Not all motion represents progress. It might be just commotion.