The universe may not be the perfect setting for intelligent life, as suggested by the anthropic principle.

The anthropic principle asserts that the universe we inhabit is perfectly suited for life, as it is in such a universe that intelligent life could emerge. This concept has been around since the 1970s but continues to provoke debate among scientists. The authors of a new article published in the Journal of Cosmology and Astroparticle Physics have proposed a method to test the anthropic principle for the first time. It may turn out that it is not valid, writes Phys.

There are weak and strong forms of the anthropic principle. The former suggests that the universe initially had all the conditions necessary for the development of intelligent life, while the latter posits that the universe must have evolved in such a way that it led to the emergence of intelligent life, specifically humans.

The anthropic principle implies that for our universe to develop as an ideal place for carbon-based life, it must have started with a specific set of initial conditions. This conclusion was reached by scientists observing the values of constants used in equations that describe the universe. If these constants were different, it is likely that intelligent life could not have emerged in the universe.

By establishing precise initial conditions and determining how the universe could evolve to its current state, scientists could compare these results with astronomical observations. This could provide evidence for or against the anthropic principle.

The authors of the article propose a method to test the validity of the anthropic principle in the coming years. To understand their proposal, it is necessary to highlight some key elements of cosmological research:

Cosmic Inflation

• At the very beginning of its existence, the universe underwent a period of rapid expansion known as cosmic inflation. In just 10 to the power of minus 36 seconds, the universe grew from an infinitely small size to approximately the size of a soccer ball. The rate of expansion then slowed, but this expansion has continued and continues today. Thus, the universe we know was formed. Direct evidence of cosmic inflation has not yet been found, but it is believed that unusual physics dominated at the very beginning of the universe's existence, influencing the formation of stars and galaxies.

Dark Matter

• Observations indicate that a significant portion of the universe is composed of dark matter, which cannot be seen directly. It only exerts a gravitational influence on ordinary matter, but its exact nature remains unknown.

Axions

• It is believed that dark matter consists of hypothetical elementary particles known as axions. They are very light, with a mass less than that of an electron. Scientists think that axions were produced in large quantities during cosmic inflation.

The authors of the article suggest using all three of these components to test the anthropic principle. It may be possible to detect primordial gravitational waves that indicate cosmic inflation. Additionally, observations of black holes may confirm the existence of axions.

It could turn out that dark matter is primarily not composed of axions, in which case the anthropic principle may not hold. However, if the opposite is proven, it would support the anthropic principle, according to scientists. The authors believe that testing based on the study of all three key components described above could lead to different outcomes: either the anthropic principle is true, or it is not.

If no confirmation of the anthropic principle is found, meaning that universal constants are different, it would indicate that different rules govern the initial conditions of the universe. Alternatively, the initial conditions may not be equally probable, or perhaps even impossible. This suggests that existing theories describing the universe must be much more complex, scientists say.