Invisible Foundations: Non Baryonic Matter Quiz

Non-baryonic matter, such as dark matter, does not experience the electromagnetic force. This means it can pass directly through other particles and itself without colliding or generating friction. This property allowed it to begin clustering under gravity without being pushed apart by the intense radiation pressure that affected normal atoms.

Observations of cosmic structures and the cosmic microwave background indicate that baryonic matter—everything made of atoms—accounts for only about 15% of the universe's total matter. The remaining 85% is non-baryonic, providing the dominant gravitational influence that governs the motion of galaxies and the large-scale structure of the cosmos.

Because non-baryonic matter could clump earlier than regular matter, it formed deep gravitational potential wells. These areas acted like cosmic traps. Once the universe cooled sufficiently, regular baryonic gas "fell" into these pre-existing wells, leading to the high-density regions necessary for the birth of the first stars.

Non-baryonic matter excludes any particles that make up the standard atomic nucleus, such as protons and neutrons. Neutrinos are a confirmed non-baryonic particle, though they are "hot." Cold Dark Matter candidates, like WIMPs, are the primary non-baryonic components responsible for building the large-scale gravitational scaffolding seen in the universe today.

If only baryonic matter existed, the universe would not have had enough time to form galaxies. Normal matter was trapped in a state of plasma by radiation for hundreds of thousands of years. Non-baryonic matter’s ability to clump immediately after the Big Bang provided a structural "head start" for galaxy formation.

The CMB contains tiny temperature variations that reflect the density of the early universe. The specific size and distribution of these fluctuations match a model where non-baryonic matter is the dominant gravitational force. Without this matter, the peaks and valleys in the CMB data would look fundamentally different.

Non-baryonic matter does not participate in nuclear fusion. Heavy elements like gold and silver are created during the life cycles and explosive deaths of stars, which are composed of baryonic matter. Non-baryonic matter only provides the gravitational environment where those stars can form and evolve.

Non-baryonic dark matter is unique because it is invisible across the entire electromagnetic spectrum and is not pushed by light (radiation pressure). However, it shares the property of mass with regular matter, allowing it to exert a gravitational pull that shapes the entire cosmic web.

Gravitational instability occurs when a region with slightly more mass pulls in surrounding material, becoming even more massive. In the early universe, these instabilities began in the non-baryonic matter component. This process transformed the nearly uniform distribution of the Big Bang into the complex network of filaments we see.

Without the gravitational seeds provided by non-baryonic matter, the expansion of the universe would have outpaced the ability of baryonic gas to clump together. The gravity of regular atoms alone is too weak to overcome cosmic expansion quickly enough to create the stars and galaxies observed in the modern era.

Redshift is the stretching of light waves as objects move away from us in an expanding universe. By measuring the redshift of distant galaxies, researchers can map out the growth of the cosmic web over time, confirming that structure formation follows the path predicted by non-baryonic matter models.

Gravitational lensing is the bending of light by mass. Because non-baryonic matter has mass, it warps the space-time around it. By observing how the light from distant background galaxies is distorted, astronomers can create detailed maps of the invisible dark matter halos that surround galaxy clusters.

Cold Dark Matter (CDM) must be non-baryonic and move at "slow" or non-relativistic speeds. This slowness is crucial because it allows the particles to stay within a small region and clump together. Fast-moving particles, known as "Hot Dark Matter," would simply fly out of small gravitational wells.

The ratio of hydrogen to helium is a direct consequence of the density of baryons during the first few minutes of the universe. If the universe were made entirely of baryonic matter, the density would have been so high that much more helium would have been produced than what we observe today.

By measuring how fast galaxies move within a cluster, scientists can calculate the total gravitational force required to keep them from flying away. These calculations consistently show that there is far more mass present than can be explained by visible stars, confirming the presence of non-baryonic matter.

While regular matter interacts with all four fundamental forces, non-baryonic dark matter is only confirmed to interact with gravity. It may also interact with the weak nuclear force, which is why it is often modeled as a WIMP, but its gravitational influence is its most prominent signature.

The Big Bang model, when combined with observations of the cosmic microwave background and primordial element abundances, provides a highly precise measurement of the universe's composition. These separate lines of evidence all converge on a universe dominated by non-baryonic matter and dark energy.

Common origin refers to the Big Bang event, where all energy and matter (both baryonic and non-baryonic) expanded from a single point. This theory is supported by the expansion of space, the composition of matter, and the leftover radiation that fills the entire sky.

In a universe dominated by cold non-baryonic matter, structure forms from the bottom up. Small fluctuations in dark matter density collapsed first to form small halos. These smaller structures then merged over billions of years to create larger galaxies and, eventually, massive galaxy clusters.

Because non-baryonic matter does not emit, absorb, or reflect any form of light, it is literally "dark" to our visual and electronic sensors. Its existence is inferred solely through its mass and the way that mass affects the visible universe through the force of gravity.