Category: SCIENCE

The majority of the matter in our Universe isn’t made of any of the particles in the Standard Model. Could the axion save the day?

Astrophysically, normal matter — even with all the different forms it can take — cannot on its own explain the Universe we observe. Beyond all the stars, planets, gas, dust, plasma, black holes, neutrinos, photons, and more, there’s an overwhelming suite of evidence suggesting that the Universe contains two ingredients whose origins remain unknown: dark matter and dark energy. Dark matter, in particular, has an incredible amount of astrophysical evidence supporting its existence and abundance — outmassing normal matter by a 5:1 ratio. Still, its particle nature remains elusive, though we’re quite certain it must have been cold, or slow-moving at early times, rather than hot, where it would have moved faster in the young Universe.

One of the leading candidates for its nature, the axion, remains compelling more than 40 years after it was first hypothesized, though it’s rarely even presented to the general public. Could this intriguing theoretical particle be the solution to the dark matter puzzle? That’s what Reggie Grünenberg wants to know, asking:

“Axions are speculative particles and hot candidates for dark matter particles that are supposed to have been created primarily in the Big Bang and since then permanently within the cores of stars through a mechanism called the Primakoff effect. This would mean that stars would ‘produce’ dark matter — and that they would need to lose this way much more mass than through nuclear fusion. And that the amount of dark matter in galaxies would grow over time, thus accelerating orbiting stars ever more. Could this model really work?”

There’s a lot to unpack here. But if we go one step at a time, you just might come away thinking that the axion could one day be the solution to the greatest cosmic mystery of all.

Although mammals may be the dominant form of life today, we’re relative newcomers on planet Earth. Here’s our place in natural history.

The evolution of life on our planet didn’t take an inevitable course to bring human beings about, but rather appears to have led to us through a series of remarkable but not necessarily mandatory events. When planet Earth first formed, all the raw ingredients for life to emerge — atoms, molecules, a potentially habitable planet at the right distance from its star — were serendipitously in place. While life itself arose relatively quickly (within the first few hundred million years) on Earth, it took billions of years for that life to become complex, differentiated, and macroscopic. The four key developments that took us there were:

• horizontal gene transfer, enabling an organism to gain useful genetic sequences from other species,
• eukaryotic cells, whereby individual cells come to possess their own specialized organelles, enabling the performance of unique functions,
• multicellularity, allowing further specialization and differentiation,
• and sexual reproduction, enabling slowly-reproducing organisms to have dramatically different DNA…

A great many cosmic puzzles still remain unsolved. By embracing a broad and varied approach, particle physics heads toward a bright future.

Just a decade ago, the field of particle physics looked to be in a state of chaos. The Large Hadron Collider had recently turned on, and although they found the Higgs boson — the final undiscovered particle predicted by the Standard Model — it failed to turn up any evidence for any of the other leading theories that would take us beyond the Standard Model. Fermilab, the prior leader in the energy frontier, shut down its main accelerator permanently, and puzzles such as:

• the origin of neutrino mass,
• the nature of dark matter,
• and the origin of the matter-antimatter asymmetry,

seemed to be stagnating, with little progress to show on either the experimental or theoretical fronts.

Moreover, particle physicists themselves seemed to be bickering and in disarray as to what they should do next. Would there be enough value to justify a new, more powerful accelerator than the Large Hadron Collider? How should we be probing the behavior of neutrinos in order to understand neutrino mass? Are we taking…

There are only a precious few minutes of totality during even the best solar eclipses. Don’t waste yours making these avoidable mistakes.

On April 8, 2024, millions of North Americans will enjoy a spectacular total solar eclipse.

For up to 4 minutes and 30 seconds, the Moon’s shadow will bring darkness to the daytime.

Avoid these five common mistakes to make the most of your experience.

1.) Don’t spend much time worrying about photography.

Totality is brief, and eclipse photography is very finicky.

Professional eclipse photographers will produce outstanding photographs, but every individual can enjoy a first-person experience.

2.) Don’t leave your eclipse glasses on during totality.

Once the Sun goes completely dark through your eclipse glasses, remove them.