Halloween is over, but every day of the year is Halloween to the Witch Nebula, a nebula that resembles a cackling witch, as you can see in this image courtesy of NASA which was posted at their web site October 31. It was taken by WISE, NASA’s Wide-Field Infrared Survey Explorer.
1C2118, or the Witch Head nebula, may look a wicked witch straight out of The Wizard of Oz, but it’s really a place where baby stars are forming and are born. The reason it looks all lit up and green in the above image is because it’s being illuminated by starlight that is reflecting off of dust in the cloud. This makes the Witch Head nebula shine with an eerie green color (it often appears to be blue). The infrared light it emits was detected by WISE.
IC2118’s molecular clouds are probably very near to the outer perimeter of the huge Orion-Eridanus so-called bubble. This bubble is a actually a vast supershell of molecular hydrogen. The expansion of this supershell creates favorable conditions for the formation of stars to occur.
NASA has written at their web site of the image: “A witch appears to be screaming out into space,” but it’s an example of how human eyes and brain structure, meaning and shapes in whatever we look at. The witchy appearance of the Witch Head nebula is an example of this tendency of the human brain to make order out of such random shapes.
The Witch Head nebula is located in the Eridanus constellation, 900 light-years from Earth. The Witch Head nebula is near to the Orion constellation, close to the knee of the hunter. It is hundreds of light-years distant from Earth, so you don’t have to worry about it getting “your little dog, too!” as the witch in The Wizard of Oz threatens to do to Dorothy’s dog, Toto.
The $320 million WISE spacecraft was shelved by NASA in 2011. Originally launched in 2009, the space observatory had completed its 10-month job of scanning the skies two times, and after that, NASA reactivated WISE to search for asteroids that might be potentially dangerous to Earth. NASA called the new program NEOWISE.
Other nebulae which have a Halloween theme to them include the Witch’s Broom nebula. It is located in the Veil Nebula, which is 1,500 light years distant from the Earth. Other nebulae resemble ghosts, or are named after wizards, and one even looks like a fiery skull.
It’s nice to see that the scientists at NASA like to get into the mood of holidays like Halloween by posting images like the Witch Head nebula on their web site. The main reason that NASA posted the image might be the promotion of science, but who says that science can’t also be fun?
Written by: Douglas Cobb