Green Bank Observatory | National Science Foundation | 2017 Apr 26
As galaxies age, some of their basic chemical elements can also show signs of aging. This aging process can be seen as certain atoms “put on a little weight,” meaning they change into heavier isotopes — atoms with additional neutrons in their nuclei.
Surprisingly, new surveys of the Milky Way with the National Science Foundation’s (NSF) Green Bank Telescope (GBT) in West Virginia, found no such aging trend for the element silicon, a fundamental building block of rocks throughout our solar system. This “ageless” appearance may mean that the Milky Way is more efficient at mixing its contents than previously thought, thereby masking the telltale signs of chemical aging.
When massive first-generation stars in young galaxies end their lives as violent supernovas, they fill the cosmos with so-called primary isotopes — elements like oxygen, carbon, and silicon with a balance of neutrons and protons in their nuclei. ...
Uniform Silicon Isotope Ratios across the Milky Way Galaxy - Nathaniel N. Monson, Mark R. Morris, Edward D. Young
- Astrophysical Journal 839(2):123 (2017 Apr 20) DOI: 10.3847/1538-4357/aa67e6