Does humanity finally understand the Universe?
We’ve identified the particles, forces, and interactions underpinning reality.
Our cosmic history — past, present, and future — was finally determined.
However, numerous puzzles remain, including these five.
1.) How did the Universe begin?
Cosmic inflation set up and preceded the hot Big Bang.
The supporting observational evidence, however, leaves much undetermined.
What “type” of inflation occurred? What preceded and/or caused inflation?
Providing answers requires new, unprecedented data.
2.) What explains neutrino mass?
Neutrinos were originally massless within the Standard Model.
Observations indicate non-zero masses: neutrinos oscillate while interacting with matter.
Are neutrinos Dirac or Majorana particles? Are there heavy, sterile neutrino species?
Their nature could break the Standard Model.
3.) Why is our Universe matter-dominated?
More matter than antimatter permeates the Universe.
However, known physics cannot explain the observed matter-antimatter asymmetry.
Fundamental symmetry violations — and LHCb experiments — could explain baryogenesis.
4.) What is dark matter?
It clumps and gravitates but passes through atoms and light.
Its indirect evidence is overwhelming; direct searches remain fruitless.
Its effects are understood, not its underlying cause.
5.) What is dark energy?
The Universe’s expansion is accelerating.
Its properties indicate a constant, positive spatial energy density.
To advance, understanding the quantum vacuum is mandatory.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.