The Horsehead Nebula is a dark pillar of dust in Orion, rising out of a dense cloud and seen in silhouette against a sheet of glowing hydrogen behind it.
At a glance
| type | nebula |
|---|---|
| distance from the Sun | 1,300 light-years (400 pc) |
| its light left it | 1,300 years ago |
| size in the piece | about 29 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 Horsehead Nebula
The horse is part of the Orion B molecular cloud, a dense pillar standing out from the cloud’s edge. It is dark because its dust blocks the light from behind it. It makes no light of its own, only a thin bright rim where starlight strikes its surface.
The glow behind it is IC 434, gas peeled off the face of the cloud by σ Orionis, a hot star to the west. The head has survived because it is denser than the gas around it, and the neck is the column of cloud in its shadow. The starlight is still eating into it, and in time the head will be worn away.
On the same cloud lie NGC 2023, a patch of dust lit blue by a hot young star, and the Flame Nebula, NGC 2024, close to Alnitak in Orion’s Belt, glowing round a cluster hidden behind its own dark lanes.
What you see in the piece
Fly to it from the WONDERS list and the horse stands out as a solid dark shape against the glowing curtain, its rim lit on the side facing σ Orionis. Pull back to see the whole edge of the cloud, with the Flame to the north.
Measured or modelled
The horse is built from a few simple shapes matched to its outline in the pictures; its thickness along the line of sight is modelled.
Questions
Why is the Horsehead Nebula dark?
It is dense dust standing in front of glowing hydrogen. The dust blocks the light from behind, so the head is seen as a silhouette.
Where is the Horsehead Nebula?
It lies in Orion, just south of Alnitak, the easternmost star of Orion’s Belt.