Milky Way Galaxy Is Much Older Than Astronomers Think; What Happened To Its Troubled Adolescence Days?

Scientists have revealed that the Milky Way galaxy sections are at least two billion years older than previously thought.

Astronomers from the Max-Planck Institute for Astronomy in Heidelberg, Germany, analyzed data collected by the European Space Agency's (ESA) Gaia mission and compared it to earlier datasets from Gaia's observation of the motion of stars in the galaxy's outskirts, also known as the anticentre, in 2020.

ISRAEL-ASTRONOMY-METEOR — The Milky Way galaxy is pictured as a Perseid meteor streaks across the sky above the Negev desert near the Israeli city of Mitzpe Ramon, on August 12, 2021, during a yearly meteor shower, which occurs when the earth passes through the cloud of debris left by the comet Swift-Tuttle. MENAHEM KAHANA/AFP via Getty Images

Milky Way Galaxy Starts Aging More Than 10 Billion Years Ago

Astronomers also used data from China's Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) to calculate the ages of about 250,000 stars.

Astronomers estimate that stars within our galaxy's "thick disc" began generating 13 billion years ago, roughly 2 billion years sooner than expected, and just 0.8 billion years after the Big Bang, according to the ESA.

Stellar objects may have filled the thick disk and the stellar halo surrounding the entire galaxy with stars due to this collision. The thin disk did not appear in the next great wave of star formation, which contained the sun, for another 5 to 6 billion years.

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Maosheng Xiang, an astronomer at the Max Planck Institute for Astronomy and one of the paper's authors, said in a statement published by the European Space Agency: "Since the discovery of the ancient merger with Gaia-Sausage-Enceladus, in 2018, astronomers have suspected that the Milky Way was already there."

However, the researcher admitted that they didn't have a clear idea of what the Milky Way exactly looked like.

The study titled "A Time-Resolved Picture of Our Milky Way's Early Formation History" was published in the journal Nature on March 23.

How Astronomers Determine Star's Age

One of the most challenging things to figure out is how old a star is. However, to simplify a complex approach, Fox6 explained that the fewer metals a star has, the older it is.

Astronomers can't determine the age of a star directly; instead, they must calculate it by comparing its features to computer models of stellar evolution. It is when the compositional data comes in handy.

Astronomers must consider the hydrogen and helium-based stuff that a star is formed of in its early phases. When a star is born, it continues to grow and produce metals within itself. As a star gets older, these metals are ejected into space.

News9Live said the new research gave dates to cosmic events and created a precise timeline of the galaxy is a significant step forward. Because of the brightness and metallicity, astronomers can calculate the star's age using computer models.