The Homunculus Nebula is a bipolar emission and reflection nebula surrounding the massive star system Eta Carinae, about () from Earth. The nebula is embedded within the much larger Carina Nebula, a large star-forming H II region. From the Latin homunculus meaning Little Man, the nebula consists of gas which was ejected from Eta Carinae during the Great Eruption, which occurred ~7,500 years before it was observed on Earth, from 1838 to 1845. It also contains dust which absorbs much of the light from the extremely luminous central stellar system and re-radiates it as infra-red (IR). It is the brightest object in the sky at mid-IR wavelengths. Within the Homunculus is a smaller Little Homunculus, and within that a shell of shocked material from stellar winds that has been called Baby Homunculus. Observational history In 1914, Eta Carinae was reported to have a faint companion and also to be non-stellar. Observations in 1944 and 1945 showed a somewhat elongated nebulosity around wide and long. It was measured to be expanding at a rate which was consistent with having originated in an explosion in the mid 19th century. At that time the shape of the nebula showed a central bulge with a single large lump to the northwest and two smaller extensions to the southeast, which was described as a Homunculus. Other observations at around the same time described a strongly orange central region in a larger fainter green nebulosity. One paper described it as looking like a "red spade-beard". Shape The Homunculus consists of two lobes, referred to as northwest (NW) and southeast (SE) based on their orientation as seen from Earth. Each is approximately wide by long. There is also a ragged equatorial skirt of material which can be seen faintly in deep images at certain wavelengths. The lobes are mostly hollow with the material strongly concentrated towards the poles. The equatorial skirt appears to contain material of the same age and younger than the lobes. It contains a much smaller mass of material than the lobes, shining mainly by reflected light which escapes most easily at equatorial latitudes. There is less dust and little molecular hydrogen compared to the lobes. The bipolar nebula is angled so that the NW lobe is further away from Earth than the SE lobe is. The whole nebula is expanding so that the SE lobe is blue-shifted and the NW lobe is red-shifted,