Astronomy
How Stellar Winds Shape Planetary Nebulae
Quick fact
Some planetary nebulae are shaped like hourglasses or butterflies, elongated by fast winds that collide with slower outflows from earlier phases.
Why this is interesting
You may have seen stunning images of planetary nebulae with glowing rings and bipolar lobes—but why do they look so different from a simple sphere? The answer lies in the stellar winds blowing from the dying star.