Galaxies
Islands of billions of stars
Name: ______________________Date: ____________
Key facts
- The Milky Way
- The Milky Way is our home galaxy – a huge spinning disc of stars, gas and dust with a bar in the middle and spiral arms. The Sun is in one of the arms. The pale band of light across a dark sky is the galaxy seen edge-on from inside.
- Large Magellanic Cloud
- The Large Magellanic Cloud is a small galaxy orbiting our own. To the eye it looks like a detached piece of the Milky Way. It contains the Tarantula Nebula, the most active star-forming region in our neighbourhood of galaxies.
- Small Magellanic Cloud
- The Small Magellanic Cloud is a dwarf galaxy orbiting the Milky Way. It is famous because studying its stars gave astronomers a way to measure the size of the universe.
- Andromeda Galaxy (M31)
- The Andromeda Galaxy is the nearest large galaxy to the Milky Way – a giant spiral with about a trillion stars. It is the most distant thing most people can see with their own eyes.
- Triangulum Galaxy (M33)
- The Triangulum Galaxy is the third-largest galaxy in our Local Group, after Andromeda and the Milky Way. It is a beautiful, loosely wound spiral, full of pink star-forming regions.
- Whirlpool Galaxy (M51)
- The Whirlpool Galaxy is a classic spiral seen face-on, tugged by a smaller companion galaxy. Their gravitational dance has sharpened its spiral arms and triggered the birth of many new stars.
- Sombrero Galaxy (M104)
- The Sombrero Galaxy has a brilliant bulge of stars and a dark lane of dust around its edge, making it look like a wide-brimmed hat. It was one of the galaxies that revealed the universe is expanding.
Quiz
Who proved in 1923 that Andromeda is a separate galaxy?
- ☐ Galileo
- ☐ Edwin Hubble
- ☐ Isaac Newton
- ☐ Carl Sagan
Henrietta Swan Leavitt’s discovery about Cepheid stars gave astronomers…
- ☐ A way to measure cosmic distances
- ☐ A new telescope
- ☐ The first photo of Mars
- ☐ A rocket design
What is the most distant thing most people can see without a telescope?
- ☐ Pluto
- ☐ The Andromeda Galaxy
- ☐ Sirius
- ☐ The Crab Nebula
Find it in the sky
Use the Sky Finder at seethestar.com. Tick what you find and write when you saw it.
| Object | Date and time | Where in the sky? | |
|---|---|---|---|
| ☐ | The Milky Way | ||
| ☐ | Large Magellanic Cloud | ||
| ☐ | Small Magellanic Cloud | ||
| ☐ | Andromeda Galaxy (M31) | ||
| ☐ | Triangulum Galaxy (M33) | ||
| ☐ | Whirlpool Galaxy (M51) | ||
| ☐ | Sombrero Galaxy (M104) |
Answers (for the teacher)
1. Edwin Hubble · 2. A way to measure cosmic distances · 3. The Andromeda Galaxy