When a medium-sized star begins to die, it sheds its outer layers forming a shell of gas and dust called a “planetary nebula,” but the term is misleading. It comes from late eighteenth century astronomers who thought their rounded shape looked similar to the planet Uranus, discovered in 1781. They named them “planetary” nebulas as a result.
Before the launch of Hubble in 1990, ground-based images suggested that planetary nebulae have simple, spherical shapes. Hubble observations revealed unprecedented details that show they are much more varied and complex. Some planetary nebulae look like pinwheels, others like butterflies, and still others like hourglasses. The extraordinary level of detail offers astronomers insights into the complex dynamics that accompany a star’s release of its outer gaseous layers before it collapses to form a white dwarf or neutron star.
In 2017, Hubble observed the remnants of an explosion caused by two surviving cores of two massive neutron stars that crashed into each other. The neutron stars collapsed into a black hole that began pulling material toward it. That whirlpool of material formed a rapidly spinning disk that generated blowtorch jets of radiation at nearly the speed of light. Hubble looked at the event just two days after the collision, allowing astronomers to measure the motion of a blob of material propelled by one of the jets slamming into it.
Learn More
Explore Other Hubble Science Highlights
Learn about some of Hubble's most exciting scientific discoveries.
Discovering the Runaway Universe
Our cosmos is growing, and that expansion rate is accelerating.
Tracing the Growth of Galaxies
Hubble is instrumental in uncovering the various stages of galactic evolution.
Studying the Outer Planets and Moons
Hubble’s systematic observations chart the ever-changing environments of our solar system's giant planets and their moons.
Seeing Light Echoes
Like ripples on a pond, pulses of light reverberate through cosmic clouds forming echoes of light.
Monster Black Holes are Everywhere
Supermassive black holes lie at the heart of nearly every galaxy.
Exploring the Birth of Stars
Hubble’s near-infrared instruments see through the gas and dust clouds surrounding newborn stars.
Shining a Light on Dark Matter
Hubble’s observations help astronomers uncover the underlying structure of the universe.
Finding Planetary Construction Zones
Hubble’s sensitivity can reveal great disks of gas and dust around stars.
Uncovering Icy Objects in the Kuiper Belt
Hubble’s discoveries helped NASA plan the New Horizon spacecraft’s flyby of Pluto and beyond.
Recognizing Worlds Beyond Our Sun
Hubble’s unique capabilities allow it to explore planetary systems around other stars.
Tracking Evolution in the Asteroid Belt
These conglomerates of rock and ice may hold clues to the early solar system.