Ten billion years ago, there was a "baby boom" of stars through galaxies including our very own Milky Way. During this time, galaxies produced stars about 30 times faster than the rate today.
Our sun was however a bit of a late bloomer. It didn't end up forming until about 5 billion years ago, making it half the age of most of the stars in the Milky Way.
In a recent study published in The Astrophysical Journal, astronomers surveyed almost 2,000 images of spiral galaxies with properties comparable to the Milky Way, making observations through both ground-based telescopes and space telescopes such as the Hubble.
The study has provided the scientists with insights into the evolution of the solar system. Study author Casey Papovich, from Texas A&M University in College Station, said their research has allowed them to envision what the Milky Way may have looked like in the past.
"It shows that these galaxies underwent a big change in the mass of its stars over the past 10 billion years, bulking up by a factor of 10, which confirms theories about their growth," Papovich said. "And most of that stellar-mass growth happened within the first 5 billion years of their birth."
The findings suggest that the Milky Way started out in small clumps of stars, which grew by gobbling huge amounts of gas that triggered a boom in stellar birth. The study shows a strong association between the star formation of galaxies and their growth in stellar mass: when the star production slowed down, the growth of galaxies decreased as well.
It also reveals that the sun formed about 5 billion years ago, which means it came into being when the Milky Way was past its stage of stellar birth boom. Being a late bloomer is not such a bad thing, though — at least not for a star in the Milky Way. Indeed, the late appearance of the sun may be one of the reasons for life on Earth.
As other stars reached old age and the end of their lives, they enriched the galaxy with elements heavier than hydrogen and helium — the building blocks of planets and organic matter on Earth.
