The Quantum World: Applications in Astronomy

Quantum physics: a deep-dive into the “very, very small”

If you’ve ever watched a sci-fi movie or taken any introductory chemistry class, you’ve undoubtedly heard the term ‘Quantum Mechanics’ mentioned. Though the term itself is widely recognised, the true purpose of quantum physics as a field is highly misunderstood - offhand, it’s generally  referred to  as the study of atoms and small molecules, but its true focus and usage is much more complex.

The science of quantum mechanics, or quantum physics, deals with the behaviour of matter and light on atomic and subatomic scales. It attempts to describe and account for the properties of molecules and atoms and their constituents - electrons, protons, neutrons, and other more esoteric particles such as quarks and gluons. These properties include the interactions of the particles with one another and with electromagnetic radiation. Put simply, quantum physics is the study of the “very, very small.” 

When studying stellar physics, quantum transitions and states play a major role in describing a star's properties. When studying galaxies and nebulae, you need quantum mechanics to describe their macroscopic behavior. The long and short of it is that to fully understand galaxies and stars, which are very massive objects, you need to know the science of the very small.

Spectroscopy

Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. 

Used primarily in the electromagnetic spectrum, it is an exploratory tool in the fields of astronomy, chemistry, and physics - allowing the composition, physical structure and electronic structure of matter to be studied at astronomical distances and at atomic and macro-scales. It’s a field that is fundamentally dependent on quantum physics because it explains the quantized nature of energy levels in atoms and molecules, allowing scientists to understand and predict spectral patterns by studying the interactions of light and matter.

By studying energy levels and transitions of light though quantum mechanics, scientists are able to predict the wavelengths or frequencies of light absorbed or emitted, thus explaining the observed spectral lines. On a molecular level, quantum physics can be used to study vibrational and rotational energy levels in molecules, enabling the study of molecular structure and dynamics in spectroscopy. 

Quantum Tunnelling: Creating star power

Stars generate energy through nuclear fusion, a process where light atomic nuclei combine to form heavier ones, releasing immense energy in the process. This process primarily involves hydrogen fusing into helium in the core, maintaining stability of the star. The energy released from nuclear fusion reactions accounts for the longevity of stellar heat and light.

The challenge of nuclear fusion lies in the fact that protons (hydrogen nuclei) must fuse to form helium, releasing energy in the process. However, protons, being positively charged, repel each other, due to Coulomb’s Law, which states that two similarly charged particles will deflect each other.

Quantum mechanics solves this issue by introducing the concept of wave-particle duality, meaning particles like protons can behave as waves, and these waves have a probability of "tunneling" through a barrier, even if they don't have enough energy to overcome it classically. When particles are presented with a "barrier" (like electromagnetic repulsion) they simply randomly tunnel through that barrier to the other side.

This quantum tunnelling allows fusion to occur at temperatures much lower than what would be predicted by classical physics, enabling the longevity of stellar light and heat.

The formation of Galaxies and Nebulae

While Quantum Field Theory (QFT) isn't directly used to model the structure of nebulae, it's essential for understanding the fundamental physics of the processes that occur within them. Examples of these processes include star formation, the evolution of the universe, and the behavior of particles and radiation in extreme environments, like the core of stars or regions around black holes. 

In particle physics, Quantum Field Theory is primarily to construct physical models of subatomic particles and in condensed matter physics to construct models of quasiparticles. As a theory it is also used to describe the behaviour of fundamental particles and forces, and model the interactions of matter and energy in the universe, including in the formation of galaxies and nebulae.

The principles of Quantum Field Theory can be relevant to understanding the physics of nebulae, and the formation of the universe. Nebulae are primarily composed of gas and dust, but they also contain particles and radiation that are described and studied by QFT researchers.

Quantum field theory can also be used to model quantum effects in extreme environments, such as the cores of stars or the regions around black holes, which can have an impact on the evolution of nebulae.

Yours truly,

Fatima Ka

Writer / Writers team