Michio Kaku, a renowned theoretical physicist, has indeed discussed the concepts of dark matter and dark energy in the universe. Let's break down what he means by his statement and address the role of atoms in relation to dark matter and dark energy.
Atoms, as traditionally understood, are the building blocks of matter and consist of a nucleus (composed of protons and neutrons) surrounded by electrons. These atoms make up the visible matter in the universe, including stars, planets, and living organisms. However, according to current scientific understanding, atoms account for only a small fraction of the total composition of the universe.
Dark matter and dark energy are theoretical concepts introduced to explain certain phenomena in cosmology:
Dark Matter: Observations of the gravitational effects within galaxies and galaxy clusters suggest the presence of an additional form of matter that does not emit or interact with light, hence the term "dark." This matter is postulated to be responsible for the gravitational forces that hold galaxies together and affect the large-scale structure of the universe. It is thought to be composed of yet-undetected particles, distinct from atoms.
Dark Energy: Dark energy is a hypothetical form of energy that is believed to be responsible for the observed accelerating expansion of the universe. Unlike dark matter, dark energy is not associated with any particular substance or particle. It is represented by a concept that describes the properties of space itself.
When Michio Kaku suggests that the universe is predominantly made up of dark matter and dark energy, he is referring to the idea that these two components are thought to constitute the majority of the universe's composition. While atoms make up the visible matter that we interact with on a daily basis, they account for only a small fraction (about 5%) of the total matter and energy in the universe. The rest is believed to be made up of dark matter (about 27%) and dark energy (about 68%).
Atoms themselves do not contain dark matter or dark energy in the traditional sense. Dark matter, as mentioned earlier, is thought to be composed of different particles not yet detected, and dark energy is a property of space itself rather than a substance contained within atoms.
It's important to note that our understanding of dark matter and dark energy is still evolving, and ongoing research aims to shed more light on these fascinating aspects of the universe.