Small Magellanic Cloud
What is Small Magellanic Cloud?
Galaxies· Distance ~200,000 ly. The smaller partner of the Large Magellanic Cloud, visible to the naked eye as a hazy cloud in southern skies. In 1912 Henrietta Leavitt studied its variable stars and found a key way to measure distances in the universe.
📍 Visible from where you are right now — computed in your browser
Its place in the sky
A galaxy, in the direction of Hydrus, spanning about 320 arcminutes of sky — 10 times the width of the full Moon.
Distance and scale
| Distance | ~200,000 ly |
|---|---|
| Diameter | ~7,000 ly |
| Stars | a few hundred million |
| Where | southern skies, in Tucana |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Discovery and name
Here Henrietta Leavitt found the Cepheid period-luminosity law in 1912 — the key to cosmic distances.
The Small Magellanic Cloud, stretched out front to back
In the sky, the Small Magellanic Cloud looks like a single cloud. Measure the distances to its stars one by one, though, and the picture changes. Its nearer and farther parts are thousands of light-years apart, so it is stretched out along our line of sight. Scientists think the gravity of the Large Magellanic Cloud has pulled it out of shape. The gas bridge between the two galaxies is thought to have been torn off in the same way.
When Leavitt did her work, she assumed that all of its stars were at the same distance. We now know that was not exactly true. Her conclusion was still right, because the galaxy is so far away, about 200,000 light-years, that a difference of a few thousand light-years was too small to change the result. What will happen to this little galaxy in the future is still uncertain.
The galaxy in depth
The Small Magellanic Cloud is a small galaxy about 200,000 light-years away. In the southern sky it looks like a faint cloud in the constellation Tucana. It is about 7,000 light-years across and holds a few hundred million stars, far fewer than its larger partner. Its shape is distorted, and scientists think the pull of the Milky Way and the Large Magellanic Cloud has stretched it this way and that. A bridge of hydrogen gas links it to the larger Cloud.
This small galaxy played a big part in modern astronomy. At Harvard Observatory, Henrietta Leavitt found and compared its variable stars on photographic plates. Since they were all in the same galaxy, they could be treated as lying at about the same distance. That let her show, in 1912, that stars which pulse more slowly are truly brighter. Hubble later used this rule to measure the distance to Andromeda.
The galaxy cannot be seen from mid-northern latitudes such as Europe, the United States or Canada. In the Sky view, switch your location to a southern city and it appears west of the Large Magellanic Cloud. Right beside it shines the bright globular cluster 47 Tucanae. That cluster, though, belongs to the Milky Way and is much closer than the Small Cloud.
Frequently asked
- How far is Small Magellanic Cloud from Earth?
- The distance of Small Magellanic Cloud is ~200,000 ly.
- How big is Small Magellanic Cloud?
- The diameter of Small Magellanic Cloud is ~7,000 ly.
- Where in the sky is Small Magellanic Cloud?
- Small Magellanic Cloud lies in the direction of Hydrus.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.