Understanding The Universe via interspecies radiative transition

“Humans are driven to explore the unknown, discover new worlds, push the boundaries of our scientific and technical limits, and then push further. The intangible desire to explore and challenge the boundaries of what we know and where we have been has provided benefits to our society for centuries.” - NASA 

During my time in quarantine, due to the current COVID-19 pandemic, I came across a recent study, published in ScienceDaily by researchers at the University of Rochester. It claims that electrons can transition between atoms and molecules of different species, a previously unknown phenomenon. Intriguing, right? While it is a known fact that atoms and molecules behave atypically at extreme temperatures and pressures, these conditions are not naturally present on earth. Such extreme matter is however abundant in the universe, specifically in the deep interiors of stars and planets. 

To provide some background, atoms consist of three basic particles - protons, neutrons and electrons. Protons and neutrons are present in the nucleus of an atom, while electrons, smallest of the three subatomic particles, are arranged in energy levels in the outer region of the atom. The lowest energy level is one closest to the nucleus and they increase in energy as they get farther from it. Electrons have an ability to transition between energy levels by emitting or absorbing photons (of energy exactly equal to the difference between the two energy levels), causing an emission line or absorption line on the atomic spectrum. This process of electrons transitioning between energy levels by absorbing or emitting photons of light is known as radiative transition, and typically occurs between the energy levels of a single atom or molecule. 

Interspecies radiative transition, as the name suggests is the jumping of electrons from one atom or molecule to another. Researchers at the University of Rochester predicted that this is possible between neighbouring atoms under high energy density (HED) conditions, because atoms and molecules are squeezed so tightly together that they become very close to one another. Under these extreme conditions, not only does interspecies radiative transition become possible, but the dipole selection rule breaks down as well. This rule states that transitions between atomic orbitals such as s-s, p-p, d-d, or f-f do not occur. Under normal conditions, this rule holds true. However, when materials are squeezed into the HED state, this rule breaks down, meaning that non-dipole emissions and absorptions can occur. 

The team utilised the density functional theory calculation, a quantum mechanical model, to perform their research. Supercomputers, at the University of Rochester's Center for Integrated Research Computing and Laboratory for Laser Energetics, were used to conduct their calculations. The results showed new emission and absorption lines in the x-ray spectra of such extreme matter systems. If proved through experimentation, these findings will change our current understanding of radiation transport.

"Thanks to the tremendous advances in high-energy laser and pulsed-power technologies, 'bringing stars to the Earth' has become reality for the past decade or two.” - Suxing Hu, scientist at the University of Rochester Laboratory for Laser Energetics.

Though in this case technology proved beneficial, as a student of Theory of Knowledge (TOK) I came to question its impact on the accuracy of predictions. Is it possible for technology to create the exact conditions present in the interiors of stars? If not, then how can predictions be made more precisely? The use of technology has implications. Even if the presence of interspecies radiative transition and breakdown of the dipole selection rule is proven through experimentation, how can we be sure of the validity of these experiments? Evidence is an important part of the natural sciences, but how is this evidence being collected? 

Scientific theories are not absolute and change with time. This study is an example of how determinism in science completely fails. While the aforementioned theories of radiative transition and dipole selection apply here on earth, they cannot be used to predict the behaviour of extreme matter in the universe. Deductive reasoning and calculations can be utilised to make predictions, however, the accuracy of these models is always arguable. Knowledge in the natural sciences is gained through logic, reasoning and empirical evidence, yet, it only gives us a picture (not an exact one) of the material world. The scientific method makes use of prior knowledge, in this context previous research and previously formulated theories. It is based on assumptions, analogies and generalizations, making us question the very Nature of Science (NOS) in the 21^st century. 

For decades, scientists have been trying to understand the workings of the universe we live in. Though this study provides some valuable insights, it makes us wonder whether we humans can possibly ever understand something that was created much before our planet came into being? 

References:

“New High-Energy-Density Physics Research Provides Insights about the Universe.” ScienceDaily, ScienceDaily, 24 Apr. 2020, www.sciencedaily.com/releases/2020/04/200424093609.htm.

Owen, Steve. Chemistry for the IB Diploma. Second ed., Cambridge University Press, 2014.

“Selection Rule.” Wikipedia, Wikimedia Foundation, 27 Feb. 2020, en.wikipedia.org/wiki/Selection_rule.

Wiles, Jennifer. “Why We Explore.” NASA, NASA, 13 June 2013, www.nasa.gov/exploration/whyweexplore/why_we_explore_main.html#.XqdByC2B3Uo.