Hoping for Light on Dark Matter

It’s one of the strangest phenomena in modern science history: trying to find something that may not exist.

Consider this a clearinghouse for dark matter articles. There have been so many lately, it’s been hard to keep up. They may all go kaput now anyway, because reporters are all excited about a possibility of “new physics” coming out of Fermilab. Physicists observed a kind of muon that doesn’t behave as the Standard Model predicts. Those interested have no shortage of articles to read about it:

• Muons: ‘Strong’ evidence found for a new force of nature (BBC News). “… the observation that the expansion of the Universe was speeding up was attributed to a mysterious phenomenon known as dark energy. But some researchers have previously suggested it could be evidence of a fifth force.“
• Strange muon behaviour hints at mysterious new particles and forces (New Scientist).
• A tiny, wobbling muon just shook particle physics to its core (Live Science).
• Is the standard model broken? Physicists cheer major muon result (Nature News).
• Mounting hope for new physics (Gutenberg University).
• Argonne scientists bolster evidence of undiscovered particles or forces in Muon g-2 experiment (Argonne National Laboratory). “Particles beyond the Standard Model could help to explain puzzling phenomena in physics, such as the nature of dark matter, a mysterious and pervasive substance that physicists know exists but have yet to detect.”
• Leading hadronic contribution to the muon magnetic moment from lattice QCD (Nature)This is the paper that started the hubbub.
• The muon’s magnetic moment fits just fine (Penn State). This group doubts the announcement of a new muon that contradicts the Standard Model. The evidence isn’t strong enough yet.

 

Antimatter Update

Since antimatter is another category of missing matter in the Big Bang universe, we include two articles about attempts to explain its mysterious absence. These are since December 2020.

CERN: discovery sheds light on the great mystery of why the universe has less ‘antimatter’ than matter (The Conversation). Lars Eklund only tries to speculate on “where the problem lies.” They admit there are indications of “something we don’t understand and that studying this topic may challenge some of our most fundamental theories in physics.”

Radioactive Molecules May Help Solve Mystery of Missing Antimatter (Caltech). A prof at Caltech and his grad student don’t answer the mystery. They only conceive of a “tabletop-based tool to search for answers to the antimatter riddle.” They’re trying radium to look for symmetry violations that might account for a slight excess of ordinary matter. Keeping busy during the pandemic is one motivation for working on this puzzle. “The radioactive-molecule approach may take years more to fully develop but Hutzler says that he has been enjoying focusing on the theoretical aspect of the work.”

Dark Matter/Energy Clearinghouse

The basic story from all the articles below is that (1) nobody knows what dark matter is; (2) detectors are getting more sensitive but still not finding it; (3) secular cosmologists need it for their theories (such as the Big Bang) to work; (4) they just won’t give up. Ditto for dark energy.

Go ahead for dark matter experiment (Phys.org). Maybe it’s made of neutrinos. Schedule tests at the LHC.

These weird lumps of ‘inflatons’ could be the very first structures in the universe (Live Science). Speculations that dark matter could be made of black holes. Depends on Alan’s Guth Goof.

New study sows doubt about the composition of 70 percent of our universe (Phys.org). Notable quote:

“If what we discovered is accurate, it would upend our belief that what we thought made up 70 percent of the universe does not actually exist. We have removed dark energy from the equation and added in a few more properties for dark matter. This appears to have the same effect upon the universe’s expansion as dark energy,” explains Steen Harle Hansen, an associate professor at the Niels Bohr Institute’s DARK Cosmology Centre.

The 1st few seconds of the Big Bang: What we know and what we don’t (Live Science). With this Tontological intro, astrophysicist Paul Sutter composes variations on the theme “we don’t know”.

Dark Energy Survey physicists open new window into dark energy (SLAC National Accelerator Laboratory). Just another exercise in hope.

Dark matter ‘annihilation’ may be causing the Milky Way’s center to glow (Live Science). Maybe. Maybe not. “A mysterious glow coming from the center of the Milky Way might be caused by annihilating dark matter — elusive matter that emits no light.” It might be. It might not be.

Dark matter is the most likely source of excess of gamma rays from galactic center (Phys.org). Likeliness is in the eye of the beholder.

Dark matter could be made of black holes from the beginning of time (Live Science). It could be. Do some time travel and go look.

Shining a new light on dark energy (Phys.org). They even have a Dark Energy Camera now, mounted on a telescope on a mountaintop in Chile. It doesn’t take pictures of Dark Energy. It just measures visible things to try to calibrate the expansion rate of the universe.

 

6 ways the hunt for dark matter changed in 2020 (Live Science). Rafi Letzter recounts the hopes and disappointments last year that came from looking at nothing.

Establishing the origin of solar-mass black holes and the connection to dark matter (Phys.org). Empty speculation.

What is the origin of black holes and how is that question connected with another mystery, the nature of dark matter? Dark matter comprises the majority of matter in the Universe, but its nature remains unknown.

Factoring in gravitomagnetism could do away with dark matter (Phys.org). Some teams think that dark matter hunters are wasting time and money. Gerson Otto Ludwig says that astrophysicists are ignoring subtle relativistic effects in rotation curves in galaxies.

The smallest galaxies in our universe bring more about dark matter to light (Phys.org). The “we’re getting warmer!” approach. “Much is unknown about dark matter, but theoretical and experimental research, from particle physics to astronomy, are elucidating more about it little by little.”

Shedding squeezed light on dark matter (Nature News). News on axion theory. Axions are one of the candidate particles for dark matter.

A new tool in the search for axions (RIKEN). Inventing a new tool to look for axions doesn’t mean they have been detected.

Scientists develop new, faster method for seeking out dark matter (Phys.org). It’s about time. Hurry up. The snipe is out there somewhere. “Now, a team of researchers have used an innovative technique called ‘quantum squeezing’ to dramatically speed up the search for one candidate for dark matter in the lab.” But there are lots of candidates.

Astronomers offer possible explanation for elusive dark-matter-free galaxies (Phys.org). Some galaxies don’t need the stuff. They might be onto something. “Astronomers offer possible explanation for elusive dark-matter-free galaxies.” One must understand that dark matter is inferred directly from theory, not observed directly.

How heavy is dark matter? Scientists radically narrow the potential mass range for the first time (Phys.org). “Scientists have calculated the mass range for Dark Matter—and it’s tighter than the science world thought.” Wow; now they capitalize the stuff. Where is the science world? Is it an exoplanet?

Mysterious ‘kick’ just after the Big Bang may have created dark matter (Live Science). Paul Sutter again with another speculation.

The Milky Way may have less dark matter than astronomers thought (New Scientist). At least this time Leah Crane says “astronomers thought” instead of the Tontological “we thought” formulation.

‘Dark sirens’ could solve one of the greatest mysteries in cosmology (Live Science). This is the most recent post about dark things. Dark sirens are gravitational wave signals from colliding neutron stars. A Penn State guy thinks that cataloguing these signals with LIGO could nail down the Hubble Constant better, which is currently in a state of controversy over disagreeing measurements. Understanding dark energy depends on an accurate determination of the Hubble Constant. It will take time and more technology improvements for these measurements to occur, however, so don’t expect answers anytime soon.

In search for dark matter, new fountain design could become wellspring of answers (Phys.org). Maybe it’s a parity violation, like holding up 5 fingers in front of a mirror and seeing 4 fingers. Sounds like 1984.

You can’t see it. You can’t feel it. But the substance scientists refer to as dark matter could account for five times as much “stuff” in the universe as the regular matter that forms everything from trees, trains and the air you breathe, to stars, planets and interstellar dust clouds.

That pretty much sums up the attitude of secular cosmologists. And you thought physics was hard science.

OK, sociologists. There are nearly two dozen recent sources to show how secular cosmologists are out of touch with reality. What will historians of science think in a few decades when the mysterious unknown stuff doesn’t show up? This will be a bigger head-shaker than phlogiston! Will taxpayers demand their money back?