A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, …

2024年12月9日 · Comets are cosmic snowballs of frozen gases, rock, and dust that orbit the Sun. When frozen, they are the size of a small town. When a comet's orbit brings it close to the …

2025年3月17日 · Comets are large objects made of dust and ice that orbit the Sun. Best known for their long, streaming tails, these ancient objects are leftovers from the formation of the …

2023年7月31日 · Comets are defined as icy bodies of frozen gases, rocks and dust left over from the formation of the solar system about 4.6 billion years ago. They orbit the sun in highly …

2025年2月25日 · Comet, a small body orbiting the Sun with a substantial fraction of its composition made up of volatile ices. Comets are among the most-spectacular objects in the …

2024年7月25日 · Comets actually have two tails – a dust tail and an ion (gas) tail. Most comets travel a safe distance from the Sun. For example, Halley's comet gets no closer than 55 million …

2025年3月11日 · Comet Gröller tops them all in terms of its closest approach to the Sun, or perihelion, which is the most distant of any comet yet found. This new comet, never gets …

2023年10月16日 · A quick and easy guide to comets, including what they are made of, where they come from and why their tails are so long.

2023年1月6日 · What are comets and where do they come from? These mysterious iceballs are key to understanding our solar system’s history. The comet 67P/Churyumov-Gerasimenko has …

2000年6月7日 · What Are Comets? * Comets are small, fragile, irregularly shaped bodies composed of a mixture of grains and frozen gases. They have highly elliptical orbits that …