Astrophysicists Reconstruct NGC 1365's 12-Billion-Year History Using 20,000 Galaxy Models
Updated
Updated · The Conversation · May 14
Astrophysicists Reconstruct NGC 1365's 12-Billion-Year History Using 20,000 Galaxy Models
4 articles · Updated · The Conversation · May 14
A March 2026 study traced spiral galaxyNGC 1365 across 12 billion years by matching its chemical makeup to one of about 20,000 simulated galaxies.
Using the du Pont telescope in Chile, researchers mapped oxygen across thousands of star-forming gas clouds, then used those heavy-element patterns to rewind the galaxy’s growth.
NGC 1365’s center appears to have formed early and enriched quickly in oxygen, while its outer disk and spiral arms likely built up more slowly through late gas inflows and mergers with dwarf galaxies.
The work is among the first to apply detailed chemical archaeology beyond the Milky Way, offering a new way to test how large spiral galaxies assembled over cosmic time.
Key uncertainties remain: similar chemical signatures can arise from different gas flows and merger histories, and scientists still do not know whether NGC 1365 is typical of spiral galaxies like the Milky Way.
Could the 'chemical archaeology' technique used on NGC 1365 reveal unexpected secrets if applied to the Milky Way or other spirals?
What mysteries about galaxy evolution remain unsolved, and how might future discoveries challenge the 'inside-out' formation model?
How might fields like archaeology or data science reinterpret the cosmic 'fossil record' uncovered in distant galaxies?
Extragalactic Archaeology Reveals 12-Billion-Year Evolution of Spiral Galaxy NGC 1365
Overview
In March 2026, a landmark study led by Lisa Kewley introduced 'extragalactic archaeology,' a new method that allowed scientists to reconstruct the 12-billion-year history of the spiral galaxy NGC 1365. This approach involves reading the chemical 'fingerprints' in a galaxy's gas and stars, especially by analyzing elements like oxygen. Young, hot stars emit ultraviolet radiation that energizes nearby gas, causing elements to produce distinct lines of light. By mapping these chemical signatures, researchers gained unprecedented insights into how galaxies like NGC 1365—and even our own Milky Way—have formed and evolved over cosmic time.