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Milky Way
Beginner
Our barred spiral galaxy.
Our barred spiral galaxy: 100–400 billion stars, 100,000 light years across; the Sun orbits the centre at 230 km/s every 230 million years, 26,000 ly from the centre.
Contains a 4 million M☉ black hole.
The band of light we see is its disc.
In more detail
The Milky Way is a barred spiral galaxy containing hundreds of billions of stars, including the Solar System. Its disk is about 100,000 light-years across.
Real-world uses
- Studying the Milky Way helps us understand other galaxies.
- Gaia and other missions map its stars in detail.
- Astronomers map the Milky Way's spiral arms and central bar to understand our place in the galaxy.
Open the interactive lesson, with simulation and quiz →
Frequently asked questions
Where is the Solar System?
About 26,000 light-years from the galactic centre, in one of the spiral arms.
Does the Milky Way have a black hole?
Yes, a supermassive black hole called Sagittarius A* at its centre.
Where is the Sun in the Milky Way?
About halfway out from the centre, in one of the spiral arms, roughly 26,000 light-years from the galactic centre.
Related topics in Particle Physics & Cosmology
Neutron stars and pulsars · Black holes in astrophysics · Galaxies · Hubble's law · Expansion of the universe · Big Bang theory