Widely recognized by astronomers, the principle of mediocrity states that the properties and evolution of the solar system are not unusual in any way. New CU Boulder research – led by CU Boulder astrophysics professor Jeremy Darling – adds to the mediocrity by showing that galaxies are, on average, quiescent relative to the early cosmos.
According to Darling, we have a fun movement that’s consistent with everything that’s known about the universe. He said, “Nothing special is happening here. We are not special as a galaxy or as observers.
The cosmic microwave background (CMB) is electromagnetic radiation left over from the formation of the universe during the Big Bang. This CMB appears warmer in the direction of our movement and cooler away from the direction of our movement. Based on this glow, scientists have hypothesized that the Sun and its planets are moving in a specific direction at a certain speed. Also, our inferred speed is a fraction of one percent of the speed of light, small but not zero.
This inference can be tested independently by counting the galaxies visible from Earth. This is possible thanks to Albert Einstein’s special theory of relativity from 1905, which explains how speed affects time and space.
But, when experts have tried to count galaxies in recent years, they have found numbers that suggest the Sun is moving much faster than previously thought, which is at odds with standard cosmology.
Undoubtedly, counting galaxies in the entire sky is a difficult task. Moreover, our galaxy is in the way. It has dust that will cause you to find fewer galaxies and make them darker as you get closer to our galaxy, Darling said.
Darling was intrigued and perplexed by this cosmological conundrum, so he decided to investigate the matter further. He was also aware of two recently published surveys: the Very Large Array Sky Survey (VLASS) in New Mexico and the Rapid Australian Square Kilometer Array Pathfinder Continuum Survey (RACS) in Australia, both of which could help improve the accuracy of the galaxy count. and shed light on the mystery of speed.
The data from these surveys helps Darling study the whole sky by combining views of the northern and southern hemispheres. Notably, the new surveys also used radio waves, which made it easier to “see” through the dust of the Milky Way, improving our view of the universe.
Analysis of the studies revealed that the number of galaxies and their brightness were in perfect agreement with the speed that scientists had previously inferred from the cosmic microwave background.
Sweetheart said, “We find a bright direction and a dark direction – we find a direction where there are more galaxies and a direction where there are fewer galaxies. The big difference is that it lines up with the early universe from of the cosmic microwave background, and that it has the right speed. Our cosmology is doing very well.
Because Darling’s findings differ from earlier findings, his paper will likely prompt various follow-up studies to either confirm or dispute his findings.
- Jeremy Darling. The universe is brighter in the direction of our motion: galaxy counts and fluxes are consistent with the CMB dipole. DO I: 10.3847/2041-8213/ac6f08