The Sun, our life-giving star, is not stationary. Like all stars in our galaxy, it moves in a vast, slow orbit around the center of the Milky Way. Recent astronomical studies estimate that the Sun has about 22 more orbits left around the galaxy before it reaches the end of its life.
While that might sound alarming at first, those orbits span billions of years, offering us both a cosmic perspective and a reminder of our place in the universe.
Understanding the Sun’s Galaxy Journey
The Milky Way galaxy is an enormous spiral system containing hundreds of billions of stars, including our own. The Sun resides in one of the galaxy's spiral arms, the Orion Arm, about 27,000 light-years from the galactic center.
Rather than staying still, the Sun orbits the center of the Milky Way at an average speed of about 828,000 kilometers per hour.
Despite this incredible speed, it takes the Sun roughly 225 to 250 million years to complete just one full orbit. This journey is known as a galactic year.
Since its formation about 4.6 billion years ago, the Sun has completed roughly 20 to 21 orbits around the Milky Way. That means we are currently living during its 22nd orbit.
Given its estimated total lifespan of about 10 billion years, the Sun is expected to complete 42 to 43 orbits in total before it dies. That leaves it with approximately 22 more galactic orbits before its life cycle comes to an end.
The Life Cycle of the Sun
The Sun is currently in the main sequence phase of its life, a long and stable period during which it converts hydrogen into helium via nuclear fusion in its core. This phase accounts for the majority of a star's life, and for the Sun, it will last for about 10 billion years in total.
As it runs out of hydrogen fuel, the Sun will enter its next phase as a red giant in approximately 5 billion years. During this time, it will expand dramatically, likely engulfing Mercury and Venus, and possibly even Earth.
After shedding its outer layers into space, it will leave behind a hot, dense core called a white dwarf, which will slowly cool and fade over trillions of years.
The Sun’s Orbit and Galactic Time
When we think of time, we usually measure it in days or years. But on the galactic scale, a single orbit of the Sun becomes a colossal unit of time, one galactic year.
To put things into perspective, when the Sun last completed a full orbit, the Earth’s continents were arranged differently, and the dinosaurs still roamed the planet.
If the Sun has around 22 more orbits left, that means it will continue to circle the galaxy for another 5 to 6 billion years. During this time, the Milky Way itself will change dramatically.
It is predicted that in about 4 billion years, our galaxy will collide with the neighboring Andromeda Galaxy, merging to form a new galactic system. Despite this cosmic event, the vast distances between stars make direct collisions between them unlikely.
The Sun and solar system are expected to survive this galactic merger, although their positions and trajectories may change.
What This Means for Earth
While the notion of the Sun having a finite number of galactic orbits might stir existential thoughts, it is not an immediate concern.
The timeline for stellar evolution operates on a scale far beyond human lifespans. Civilization, as we know it, has only existed for a fraction of a single galactic year, just around 10,000 years.
However, understanding our Sun's orbit helps put our existence into a broader cosmic context. It reminds us that we are passengers not only on a spinning planet but also on a star making its slow, graceful journey through space.
The Sun’s limited number of orbits is a natural consequence of the life cycle of stars and the dynamic structure of galaxies.
A Ticking Cosmic Clock
The idea that the Sun has 22 orbits left before it dies is not meant to invoke panic. Rather, it’s a poetic reflection on the rhythms of the universe.
Our star is part of a galactic ballet that continues regardless of human activity, and its movement marks the passage of deep cosmic time.
For now, the Sun remains in its prime, reliably illuminating our solar system and sustaining life on Earth.
But astronomers continue to study its motion, composition, and future, using this knowledge to better understand not just our own star, but the countless others scattered throughout the Milky Way.
In the end, the Sun’s remaining orbits are a humbling reminder: we are part of something far greater, moving slowly and steadily through the grand architecture of the cosmos.
