"The Hourglass Nebula defies explanation. A small hourglass nests in a large one, but the dead star isn't at the center of either one. Two inner rings circle the eye at right angles. But why? If there’s a binary star, it wouldn’t account for this one-of-a-kind shape."
An hourglass could form from swift stellar winds pushing dense clouds at the star’s equator up and down into symmetric shapes. Or a strong magnetic field could sculpt ionized gas into an hourglass. But an off-center star rules out both scenarios. It’s still a mystery.
Generator Unlocked
Butterfly Nebula
About one in 10 nebulae are bipolar, like the Hourglass, but shapes vary widely. The Butterfly Nebula has wings instead of rings. A very hot dead star at center is jetting out high-speed gas from the poles. The outflows are surprisingly symmetrical, like a mirror image.
Off-Center Star
Achievements[]
Icon
Name
Description
Requires
Red Rectangle Nebula
The Red Rectangle Nebula is straight edged instead of round or butterfly winged. Why? A pair of stars orbit closely at the center in a gravitational tango. Their tight dance confines the bipolar outflow of gas to four narrow cones in an X shape.
Hourglass Nebula Rank 3
Ant Nebula
The bipolar Ant Nebula probably has two stars, one of which is very similar to how the Sun will look in about 5 billion years. Skinny “ant legs” at either end stretch its width to 1.5 light years. They are streams of speedy gases zipping easily through slow matter.
Hourglass Nebula Rank 6
Trivia[]
Image of the Hourglass Nebula, taken by Hubble Space Telescope in 1996.
Engraved Hourglass Nebula, shortly Hourglass Nebula (also known as MyCn 18), is a young planetary nebula in the southern constellation Musca.