Do the constants of nature—the numbers that determine how things behave, like the speed of light—change over time as the universe expands? Does light get a little tired traveling great cosmic distances? Dark matter and dark energy were believed to explain these cosmological phenomena, but recent research shows that our universe has expanded without dark matter or dark energy.
Removing dark matter and dark energy solves the “impossible early galaxy problem,” which arises when we try to account for galaxies that do not conform to expectations about size and age. Finding an alternative to dark matter and energy that is consistent with existing cosmological observations, including the distribution of galaxies, is possible.
Read more: How old is the universe exactly? A new theory suggests it has been around for twice as long as believed
Dark matter
Dark matter is a hypothetical form of matter that does not interact with ordinary matter in any way except through gravity. It was proposed as a theoretical way to explain our astrophysical and cosmological observations. Ordinary matter can travel through dark matter without any resistance and vice versa.
In space, gravitational pull determines the speed at which an object spins. A higher-than-expected velocity of surrounding spinning objects is attributed to the existence and gravitational pull of dark matter.
The gravitational pull of dark matter can also bend light rays, causing a gravitational lensing effect just like normal matter. This allows the measurement of dark matter in the object causing the bending, such as in galaxies and galaxy clusters.
The strongest support for the existence of dark matter comes from observed small variations in the cosmic microwave background radiation (radiation left over from the big bang), measured with increasingly high precision.
Another argument for the existence of dark matter is that the large-scale structures of the universe, such as galaxies, would not have been able to form without dark matter within the finite age of the universe.
(NASA Goddard Space Flight Center/Stephen Walker)
Alternative theories
There are alternatives to the dark matter that accounts for many astrophysical observations. The oldest and most popular theory is Modified Newtonian Dynamics (MoND), which suggests that Newton’s inverse square law of gravitational attraction is a simplified version of a full force that becomes perceptible only at great distances large when Newton’s force becomes negligible.
Another alternative is a version of the MoND that includes relativistic Einstein effects and explains observations where the MoND is limited, such as the cosmic microwave background radiation. Then there is the proposed theory of delayed gravity that also claims to match such observations.
Astronomers are surprised to learn that many observations show a complete absence of dark matter or dark matter-deficient structures. This leads one to question its existence.
An explanation must then be found for what might have created the problem, such as tidal forces exerted by the passage of nearby galaxies removing dark matter. Even the mass of the Milky Way has recently been determined to be much smaller than expected by cosmology.
Does dark matter exist?
Recent discoveries cast doubt on the existence of dark matter. Despite extensive research and billions of dollars in investment, there has been no direct detection of any dark matter.
Dark energy theory negates the gravitational pull of matter, causing the universe to expand faster over time, as observed. Correlated changes in the constants of nature, called the Codependent Coupling Constant (CCC), achieve the same effect by weakening the gravitational pull and other forces of nature over time, eliminating the need for dark energy.
Combined with the tired light (TL) effect that posits that light slows down as a result of energy loss, such a cosmological model has no place for dark matter. The CCC approach can also replace the dark energy-like constant thought to be responsible for the extremely rapid expansion of the universe after the Big Bang, called inflation.
The age of the universe is determined by the historical rate of expansion of the universe and can vary depending on the model used for the expansion. Measuring the redshift of exploding stars, called type 1a supernovae, and their observed brightness can determine the rate of expansion.
Redshift is the decrease in spectral line frequencies depending on the recession rate of the emitting object, similar to the frequency of an ambulance siren receding. By allowing the redshift due to the exhausted light effect to coexist with the expansion redshift, the expansion rate of the universe decreases and the age of the universe increases.
(NASA, ESA, CSA, STScI, B. Robertson (UC Santa Cruz), B. Johnson (CfA), S. Tacchella (Cambridge), P. Cargile (CfA))
This new model predicts that the universe is older than we think it is—26.7 billion years in the CCC cosmology compared to 13.8 in the standard cosmology—and allows galaxies and their clusters to form without dark matter. The increase in the age of the universe at the earliest times when structures began to form was up to 100 times greater in the new model.
The lack of dark matter that reduces the gravitational force and increases the time for matter to collapse to form structures is greatly compensated by the increased age in the CCC model.
Slowing down time
The expansion of the universe causes time to appear to slow down when observing distant galaxies. The CCC+TL model is consistent with observations showing a time dilation effect that appears to slow down the clock in distant objects.
New criticisms of the CCC+TL model rely on flawed hypotheses, such as the shortcomings presented by the concept of tired light, or inaccurate analyses, including redshift analysis of cosmic microwave background temperatures. A single free parameter in the CCC cosmology determines the variation of all constants that asymptotically approach their respective constant values. As in the standard cosmology, the CCC cosmology has only two free parameters. Adding tired light to CCC does not require any additional parameters for free.
The Standard Model of cosmology requires dark matter to fit observations, such as calculating redshift when measuring supernova luminosity. Dark matter is also used to explain physical processes such as the rotation curves of galaxies, galaxy clusters or gravitational lensing. Using CCC+TL cosmology means that we must seriously consider alternative physical processes to account for astrophysical observations previously attributed to dark matter.