What Is a Comet? | NASA Space Place – NASA Science for Kids
2024年10月11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 solar system 4.6 billion years ago.
Rare comet to streak across night sky. Here’s how you can see it
2024年10月10日 · A comet discovered last year — known as C/2023 A3 Tsuchinshan-ATLAS — is set to make a close approach to Earth in the coming days.
Comet - Wikipedia
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, gravitationally unbound atmosphere or coma surrounding the nucleus, and sometimes a tail of gas and dust gas blown out from the coma.
Comets - NASA Science
Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices. They range from a few miles to tens of miles wide, but as they orbit closer to the Sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet.
Comet | Definition, Composition, & Facts | Britannica
2 天之前 · 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 sky, with their bright glowing comae and their long tails. Comets can appear at random from any direction as they move in eccentric orbits around the Sun.
Comets: Everything you need to know | Space
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 elliptical...
What Are Comets | What Does a Comet Look Like - Star Walk
3 天之前 · A comet is a space object primarily composed of ice, dust, and rocky material. Comets orbit the Sun and are often categorized based on their orbital periods: short-period comets take less than 200 years to orbit the Sun, while long-period comets take more than 200 years.
Comets are icy balls of gas and dust - EarthSky
2022年11月24日 · Comets are icy balls of gas, dust and rock that orbit the sun. Astronomers believe most comets are leftovers from the formation of the sun and planets. In fact, comets come...
What are comets and where do they come from? - Astronomy …
2023年1月6日 · When these objects are perturbed and sent sailing into the inner solar system, they are heated by the Sun and transformed into the ethereal apparitions we know as comets.
Comets: Facts - Science@NASA
The pressure of sunlight and high-speed solar particles (solar wind) can blow the coma dust and gas away from the Sun, sometimes forming a long, bright tail. Comets actually have two tails – a dust tail and an ion (gas) tail. Most comets travel a safe distance from the Sun.