Reference Terms
from Wikipedia, the free encyclopedia
Planetary nebula
A planetary nebula is an astronomical object consisting of a glowing shell of gas and plasma formed by certain types of stars at the end of their lives. They are in fact unrelated to planets; the name originates from a supposed similarity in appearance to giant planets. They are a short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years. About 1,500 are known to exist in the Milky Way Galaxy. Planetary nebulae are important objects in astronomy because they play a crucial role in the chemical evolution of the galaxy, returning material to the interstellar medium which has been enriched in heavy elements and other products of nucleosynthesis (such as carbon, nitrogen, oxygen and calcium). In other galaxies, planetary nebulae may be the only objects observable enough to yield useful information about chemical abundances.
Related Stories
1
2
Space & Time News
April 14, 2026
Apr. 12, 2026 A major international effort has produced an ultra-precise measurement of the Universe’s expansion rate, confirming it’s faster than early-Universe models predict. By linking multiple distance-measuring techniques, scientists ruled out simple ...
Apr. 10, 2026 Scientists have proposed a surprising new way to detect gravitational waves—by observing how they change the light emitted by atoms. These waves can subtly shift photon frequencies in different directions, leaving behind a detectable signature. ...
Apr. 9, 2026 Earth’s nights are steadily getting brighter overall, but the changes vary dramatically by region. Rapid urban growth is lighting up countries like China and India, while parts of Europe are dimming due to energy-saving efforts and new lighting ...
Apr. 8, 2026 Planetary exploration may be about to get a major speed boost. Researchers tested a semi-autonomous robot that can move from rock to rock, analyzing each without waiting for human instructions. The system completed missions up to three times faster ...
Apr. 3, 2026 A new concept suggests SpaceX’s Starship could revolutionize a future mission to Uranus, one of the solar system’s most overlooked planets. By refueling in orbit and helping slow the spacecraft on arrival, it could cut travel time nearly in ...
Mar. 20, 2026 A mysterious spike of platinum buried deep in Greenland’s ice has long fueled theories of a catastrophic comet or asteroid strike 12,800 years ago—possibly triggering a sudden return to icy conditions known as the Younger Dryas. But new research ...
Mar. 14, 2026 Mars didn’t always look like the barren world we see today. Over billions of years, the Sun’s solar wind stripped away much of its atmosphere, helping transform it from a warmer, wetter planet ...
Feb. 24, 2026 Scientists have proposed a surprising connection between solar flares and earthquakes. When solar activity disturbs the ionosphere, it may generate electric fields that penetrate fragile fracture zones in Earth’s crust. If a fault is already ...
Feb. 2, 2026 NASA’s Perseverance rover has just made history by driving across Mars using routes planned by artificial intelligence instead of human operators. A vision-capable AI analyzed the same images and terrain data normally used by rover planners, ...
Feb. 2, 2026 Hidden lava tunnels on the Moon and Mars could one day shelter human explorers, offering natural protection from radiation and space debris. A European research team has unveiled a bold new mission concept that uses three different robots working ...
Jan. 28, 2026 Low-Earth orbit is more crowded—and fragile—than it looks. Satellites constantly weave past each other, burning fuel and making dozens of evasive maneuvers every year just to stay safe. A major solar storm could disable navigation and ...
Jan. 19, 2026 Physicists have unveiled a new way to simulate a mysterious form of dark matter that can collide with itself but not with normal matter. This self-interacting dark matter may trigger a dramatic collapse inside dark matter halos, heating and ...
Latest Headlines
updated 12:56 pm ET
Apr. 13, 2026 A colossal “cosmic volcano” has erupted in deep space, as a supermassive black hole in galaxy J1007+3540 roars back to life after nearly 100 million years of silence. Astronomers captured ...
Apr. 12, 2026 Mars may be hostile, but it might not be entirely unlivable. In lab experiments, yeast cells survived simulated Martian shock waves and toxic perchlorate salts—two major environmental threats on ...
Apr. 10, 2026 A mysterious glow of gamma rays at the center of the Milky Way has long hinted at dark matter, but the lack of similar signals in smaller dwarf galaxies has cast doubt on that idea. Now, researchers ...
Apr. 8, 2026 For all its ancient, familiar features, the Moon is still changing—and sometimes in dramatic ways. Scientists recently identified a fresh 22-meter-wide crater by comparing orbital images taken ...
Apr. 8, 2026 A bizarre, record-breaking neutrino detected in 2023 may have originated from an exploding primordial black hole—a relic from the early universe. ...
Apr. 6, 2026 Earth may have won a cosmic chemistry lottery. Researchers found that during the planet’s earliest formation, oxygen had to be in an extremely narrow “Goldilocks zone” for two life-essential ...
Apr. 6, 2026 A strange “forbidden” planet spotted by the James Webb Space Telescope is turning planetary science on its head. TOI-5205 b, a Jupiter-sized world orbiting a small, cool star, has an atmosphere ...
Apr. 6, 2026 Scientists have taken a major step toward probing one of physics’ biggest mysteries—how gravity and quantum mechanics fit together—by creating the first unified way to detect tiny “ripples” ...
Apr. 5, 2026 Mars may look like a quiet, dusty world, but it’s actually buzzing with hidden electrical activity. Powerful dust storms and swirling dust devils ...
Apr. 4, 2026 Dying stars may be wiping out nearby giant planets as they expand into red giants. Astronomers found that these close-in planets become increasingly rare around more evolved stars, suggesting many ...