How old is the Milky Way?

The Milky Way began forming around 13.6 billion years ago, shortly after the first stars appeared. It has been growing and changing ever since through mergers and star formation.

Will the Milky Way collide with Andromeda?

Yes, in about 4.5 billion years the Milky Way and Andromeda will merge. The collision will be slow and dramatic, eventually forming a new elliptical galaxy.

Where is the Sun located in the Milky Way?

The Sun sits in the Orion Arm, one of the smaller spiral arms, roughly 26,000 light-years from the galactic center. We are not near the center or the edge.

The Milky Way | Formation of Our Home Galaxy

Type

Spiral Galaxy

Stars

200–400 billion

Age

~13.6 billion years

Our Location

Orion Arm

Our Star

The Sun (4.6 billion years old)

Our place among the stars

The Milky Way did not form in isolation. It grew through the repeated merging of smaller protogalaxies in the early universe. Over billions of years, these mergers, combined with the steady collapse of gas into a rotating disk, created the majestic spiral galaxy we live in today.

A Violent Youth

Early in its life, the Milky Way was much more chaotic. It swallowed dozens of smaller galaxies. The remnants of some of those ancient mergers can still be seen today as streams of stars in the galactic halo. Our galaxy's central bulge and thick disk are direct evidence of this violent past.

Around 4.6 billion years ago, in one of the galaxy's quieter spiral arms (the Orion Arm), a cloud of gas and dust collapsed to form our Sun and the Solar System. We are relative newcomers in a very old galaxy.

KEY INSIGHT

The Sun is not the center of the Milky Way — it orbits the galactic center at about 828,000 km/h, completing one full lap every 225–250 million years. We are currently on our 20th or 21st orbit since the Sun was born.

Fascinating Facts

The Milky Way contains an estimated 200–400 billion stars and is about 100,000 light-years across.
It is on a collision course with the Andromeda Galaxy in roughly 4.5 billion years.
The Solar System completes one orbit around the galactic center every 225–250 million years (a galactic year).
The Milky Way has a supermassive black hole at its center (Sagittarius A*) with 4 million solar masses.
Most of the Milky Way’s mass is dark matter, which we cannot see but whose gravity shapes the galaxy.
The Sun is a third-generation star — it formed from material enriched by many previous generations of stars.

ORIGINAL VISUAL RECONSTRUCTION

Our galactic home

Cinematic scientific visualization

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The chaotic birth of our home galaxy — the Milky Way — through ancient mergers and gravitational collapse in the early universe.

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Why Our Galaxy Matters

The Milky Way is not just our address in the universe. It's the environment that made everything possible. The Sun formed in a relatively quiet corner of a mature galaxy, protected enough for planets to form and life to eventually take hold. Without the long, turbulent history of our galaxy, we wouldn't be here to wonder about it.

Continue the Journey

The First Stars Birth of the Solar System The Theia Impact All Cosmic Origins →

Milky Way Through Time

Time	Stage	What Was Happening
~13.6 billion years ago	First protogalaxies	Small clumps of gas and stars begin merging.
~10–12 billion years ago	Major mergers	The Milky Way swallows several smaller galaxies.
~4.6 billion years ago	Sun forms	Our star is born in the Orion Arm.
Today	Mature spiral galaxy	Still growing slowly through minor mergers and star formation.

Milky Way Formation