Are All Galaxies Made Up of the Same Elements, or Could There Be Unknown Elements?

The composition of galaxies in the cosmos has been a subject of intense scientific inquiry. A common misconception is that each galaxy may be a unique blend of elements, perhaps containing elements yet to be discovered. However, our current understanding of astrophysics suggests that despite variations in composition, all galaxies share the same fundamental elements.

Common Elements in Galaxies

Every galaxy, from the nearest one, such as the Milky Way, to the farthest known galaxy, is fundamentally composed of the same key elements:

Hydrogen Helium Carbon Oxygen Nitrogen Iron

These elements are produced through stellar nucleosynthesis within stars and supernova explosions. Stellar nucleosynthesis involves the fusion of lighter elements into heavier elements inside the cores of stars. Supernovae, particularly Type II supernovae, play a crucial role in distributing these heavier elements across the galaxy.

Variations in Element Abundance

Although the types of elements are consistent, their abundances can vary significantly between galaxies. This variation is influenced by several factors:

Star Formation Rates: Galaxies with higher rates of star formation tend to have more recently formed stars, which contain higher amounts of heavier elements, known as metals in astrophysical contexts. Stellar Evolution History: The history of stellar evolution in a galaxy can affect the abundance of certain elements. For instance, older galaxies may have lower metallicity due to fewer generations of star formation. Interactions with Other Galaxies: Collisions and mergers between galaxies can redistribute elements, leading to varying compositions.

The Potential for Undiscovered Elements

While the known periodic table only reaches up to element 118, Oganesson, the search for new elements continues. Theoretical physics suggests that there could be unknown elements, especially those that might be stable under extreme conditions not yet explored:

Stability under Extreme Conditions: Some elements may have stability in environments that have not yet been encountered, such as extreme pressure or high temperatures. Unexplored Environments: There are theoretical possibilities for elements in high-energy environments, such as inside neutron stars, that have not been observed.

Physics and the Periodic Table of Elements

The existence and stability of elements are governed by the fundamental laws of physics. Quantum field theory and the standard model dictate the subatomic particles and the stability of atomic nuclei. For instance, the emission and absorption spectra of each element have unique fingerprints that can be observed in the light from distant galaxies, indicating the presence of hydrogen, helium, and other lighter elements.

The periodic table of elements is highly consistent throughout the universe. Theoretical changes to basic physics or physical constants would produce measurable differences in atomic spectra, providing strong evidence that the laws of physics are invariant across the observable universe.

Although there is a theoretical possibility for new, semi-stable high-mass elements (in the mid-120's), these are predicted to have extremely short half-lives—less than a day. Therefore, even in supernovae, these elements would not persist long enough to have a significant impact on the composition of galaxies.

Planets in other galaxies will still be composed of the same basic elements—Hydrogen through Iron, with traces of heavier elements, and an array of chemical compounds resulting from their combination.

Conclusion

While the variations in the abundance of elements between galaxies are well-documented and influenced by various factors, the underlying elements remain consistent. The search for new elements continues, but the fundamental elements that make up all galaxies are well-established and consistent with the laws of physics as we understand them.