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Galaxies & Deep Sky
Everything past the solar system: nebulae where stars are born, clusters that formed together, the structure of our own Milky Way, and the reach of the universe out to the visible horizon.
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The Milky Way: Reading Our Own Galaxy from Inside It
What we've been able to work out about the Milky Way's size, shape, and structure while stuck inside it — and how to read the summer sky as a slice through its disk.
Dmitry Shteynbuk · February 8, 2026 · 3 min read
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3 publishedGalaxies & Deep Sky·
How Far Is Far: The Cosmic Distance Ladder
Astronomers measure distance in overlapping steps, each calibrated by the one below. Six rungs take us from the solar system to the edge of the observable universe.
Dmitry Shteynbuk · 3 min read
/articles/distance-ladderGalaxies & Deep Sky·
Nebulae: The Four Kinds and How to See Them
Emission, reflection, dark, and planetary nebulae — what makes each one glow (or not), and the best-known example of each you can actually observe.
Dmitry Shteynbuk · 3 min read
/articles/nebulae-four-kindsTerms to know
Full glossary →- Nebula
- A cloud of gas and dust in interstellar space.
- Open cluster
- A loose group of a few hundred to a few thousand stars born together.
- Globular cluster
- A dense, spherical swarm of hundreds of thousands of ancient stars.
- Redshift
- The stretching of light to longer wavelengths as an object moves away.
- Cepheid variable
- A pulsating giant star whose period reveals its true luminosity.
- Parallax
- The apparent shift of a nearby star against the background as Earth orbits the Sun.