Astronomers have recently made a perplexing discovery; some asteroids have densities higher than any elements currently known on Earth. The implications of this finding suggest that these asteroids may contain unknown types of “ultradense” matter that defy traditional understanding in the field of physics. In an effort to explain this phenomenon, a team led by Jan Rafelski at the Department of Physics, The University of Arizona, Tucson, has proposed the existence of superheavy elements with atomic numbers beyond the limits of the periodic table. Through their research, using the Thomas-Fermi model of atomic structure, they have explored the properties of these elements and have even ventured into the realm of even more exotic forms of ultra-dense material. Their groundbreaking work has been published in The European Physical Journal Plus.
Superheavy elements are characterized by having a high number of protons, generally exceeding Z>104. These elements can be further divided into two groups: those with atomic numbers ranging from 105 to 118, which have been experimentally created but are highly unstable and short-lived, and elements with Z>118, which have yet to be observed but have properties predicted for them. Notably, a theoretical “island of nuclear stability” is anticipated around Z=164. As a general trend, the density of elements tends to increase with their atomic mass, leading to the expectation that superheavy elements will exhibit remarkable density. For reference, the densest stable element known on Earth is osmium with a density of 22.59 g/cm³, approximately double that of lead. Objects with densities surpassing this threshold are referred to as “compact ultradense objects” or CUDOs.
Drawing inspiration from the anomalously dense asteroid named 33 Polyhymnia, which has a calculated density of approximately 75 g/cm³, Rafelski theorizes that Polyhymnia and similar asteroids may be comprised of elements with atomic numbers exceeding Z=118, potentially accompanied by other forms of ultradense matter. To shed light on this hypothesis, Rafelski and his research team, including Evan LaForge and Will Price, employed the relativistic Thomas-Fermi model of the atom to calculate the atomic structure and properties of ultraheavy elements. Despite the model’s inherent imprecision, its advantage lies in the ability to explore atomic behavior beyond the known periodic table, making it an excellent tool for this investigation.
Through their calculations, the researchers confirmed the prediction of stable atoms with approximately 164 protons in their nuclei. Additionally, their findings suggested that an element with Z=164 would boast a density ranging from 36.0 to 68.4 g/cm³, approaching the observed value for astroid Polyhymnia. Since the model takes into account the charge distribution within the atomic nucleus, it can also extend its simulations to include even more exotic substances like alpha matter, which is composed entirely of isolated helium nuclei or alpha particles.
The notion that certain asteroids may house materials not found on Earth has captivated the interest of “space miners” who seek to harness the valuable metals, such as gold, that are hypothesized to exist near the asteroid’s surface. Expanding our knowledge of ultradense matter and superheavy elements could unveil new avenues for resource exploration and space research.
The mystery of ultradense matter continues to intrigue scientists and challenge established theories in physics. The proposal of superheavy elements beyond the current limits of the periodic table presents an intriguing avenue for further exploration. Through innovative modeling techniques and calculations, Rafelski and his team shed light on the potential atomic structure and properties of these elements. Further research in this field could provide valuable insights into the composition of asteroids and expand our understanding of the universe’s hidden mysteries. As Rafelski aptly concludes, “All super-heavy elements, whether highly unstable or simply unobserved, have been collectively labeled as ‘unobtainium.'” The quest to obtain these elusive elements continues, fueled by curiosity and a desire to unlock the secrets of the cosmos.
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