The Small Magellanic Cloud is a dwarf galaxy orbiting the Milky Way with its larger twin, the place where the Cepheid key to cosmic distances was discovered.
At a glance
| type | galaxy |
|---|---|
| distance from the Sun | 202,000 light-years (62 kpc) |
| its light left it | 202,000 years ago |
| size in the piece | about 20,000 light-years acrossmodel |
Read off the piece’s own catalogue, the same values it draws with. Model marks a property of the piece’s galaxy model rather than a measurement.
About Small Magellanic Cloud
The Small Magellanic Cloud is a dwarf irregular galaxy in the southern sky, in Tucana, visible to the naked eye as a smudge of light. It is poor in heavy elements compared with the Milky Way, so its young stars resemble those that formed in the early universe, and its brightest star-forming regions, above all NGC 346, are studied for that reason.
Henrietta Leavitt, studying variable stars in the Small Magellanic Cloud, found that the brighter a Cepheid variable is, the longer it takes to pulse. Since all those stars lay at roughly the same distance, the relation was real, and it became the tool that later measured the distance to Andromeda and the expansion of the universe.
It is connected to the Large Magellanic Cloud by a bridge of gas and stars, and the pair trail the Magellanic Stream, a long ribbon of gas pulled out by their mutual tides and the Milky Way’s.
What you see in the piece
It fades in on the pull-back toward the Local Group; from the Sun’s side it sits near 47 Tucanae on the sky, but the two separate at once when you leave the Galaxy.
Measured or modelled
Its depth along the line of sight appears large, consistent with the galaxy being torn by tides, but its true three-dimensional shape is still being worked out. The extent drawn here is modelled.
Questions
How far away is the Small Magellanic Cloud?
The Small Magellanic Cloud is about 202,000 light-years (62 kpc) from the Sun.
Why is the Small Magellanic Cloud important?
It was in this galaxy that Henrietta Leavitt found the link between a Cepheid variable’s period and its brightness, the relation that made it possible to measure distances to other galaxies.