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.
![collage of Hubble views of planetary nebulas](https://science.nasa.gov/wp-content/uploads/2023/04/nebulacollage_0.png?w=4096&format=png)
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.
![The Crab Nebula](https://science.nasa.gov/wp-content/uploads/2023/04/hubble_crabnebula-jpg.webp?w=4096&format=png)
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.
NASA, ESA, R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation), and P. Challis (Harvard-Smithsonian Center for Astrophysics)
![Two red rings overlap and bisect a center yellow ring that surrounds a bright-white point of light. As the animation progresses, the rings are viewed from the side revealing how they expanded outward from the central star.](https://science.nasa.gov/wp-content/uploads/2023/04/sn1987a.gif?w=4096&format=png)
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Explore Other Hubble Science Highlights
Learn about some of Hubble's most exciting scientific discoveries.
![Cepheid star in Andromeda galaxy (Hubble observations)](https://science.nasa.gov/wp-content/uploads/2023/04/stsci-prc11-15a-jpg.webp?w=4096&format=png)
Discovering the Runaway Universe
Our cosmos is growing, and that expansion rate is accelerating.
![Hubble Ultra Deep Field image](https://science.nasa.gov/wp-content/uploads/2023/04/hubble_ultra_deep_field_stsci-prc04-07a-jpg.webp?w=4096&format=png)
Tracing the Growth of Galaxies
Hubble is instrumental in uncovering the various stages of galactic evolution.
![Hubble image left to right: Jupiter, Uranus, Saturn, Neptune](https://science.nasa.gov/wp-content/uploads/2023/04/hubble_opal_composite.png?w=4096&format=png)
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.
![Hubble view of an expanding halo of light around star v838 monocerotis](https://science.nasa.gov/wp-content/uploads/2023/04/hubble-v838mon-heic0405a-jpg.webp?w=4096&format=png)
Seeing Light Echoes
Like ripples on a pond, pulses of light reverberate through cosmic clouds forming echoes of light.
![Hubble observations of galaxies' centers](https://science.nasa.gov/wp-content/uploads/2023/04/prc97-01-jpg.webp?w=4096&format=png)
Monster Black Holes are Everywhere
Supermassive black holes lie at the heart of nearly every galaxy.
![Hubble observations of Carina Nebula section](https://science.nasa.gov/wp-content/uploads/2023/04/eta-carinae-hubble20thpic-jpg.webp?w=4096&format=png)
Exploring the Birth of Stars
Hubble’s near-infrared instruments see through the gas and dust clouds surrounding newborn stars.
![depiction of gravitational lensing](https://science.nasa.gov/wp-content/uploads/2023/04/macs_j1149-2223-jpg.webp?w=4096&format=png)
Shining a Light on Dark Matter
Hubble’s observations help astronomers uncover the underlying structure of the universe.
![Thirty proplyds in a 6 by 5 grid. Each one is unique. Some look like tadpoles, others like bright points in a cloudy disk.](https://science.nasa.gov/wp-content/uploads/2021/12/hubble-orion-proplyds-heic0917aa-jpg.webp?w=4096&format=png)
Finding Planetary Construction Zones
Hubble’s sensitivity can reveal great disks of gas and dust around stars.
![Three views of Pluto. Three mottled circles in colors of yellow, grey, rusty-orange, and black.](https://science.nasa.gov/wp-content/uploads/2023/01/hubble-pluto-stsci-01evsrjcapn1afkxej1d7e1njd.png?w=4096&format=png)
Uncovering Icy Objects in the Kuiper Belt
Hubble’s discoveries helped NASA plan the New Horizon spacecraft’s flyby of Pluto and beyond.
![Comma shaped curved cloud of gases in bright white edged with bright-pink star forming regions, and threaded with rusty-brown tendrils of dust at center and throughout the comma shaped merger. All set against the black of deep space.](https://science.nasa.gov/wp-content/uploads/2021/12/hubble-antennaegalaxies-potw1345a-jpg.webp?w=4096&format=png)
![Blue background. Center of image is a disk blocking the light of a star. Below and just to the left of the disk, at about seven o'clock, is a bright white point. This is PDS 70b.](https://science.nasa.gov/wp-content/uploads/2021/12/hubble-pds70b-stsci-h-p2121c-f-1280x1280-1-jpg.webp?w=4096&format=png)
Recognizing Worlds Beyond Our Sun
Hubble’s unique capabilities allow it to explore planetary systems around other stars.
![animation of a binary asteroid with a shifting tail](https://science.nasa.gov/wp-content/uploads/2023/04/comet3.gif?w=4096&format=png)
Tracking Evolution in the Asteroid Belt
These conglomerates of rock and ice may hold clues to the early solar system.