What's a Nebula?

Answer 1

a nebula is any interstellar cloud of gas or plasma and dust composed mostly of hydrogen atoms or ions. there are three kinds. an emission nebula is a cloud of hot plasma and dust which fluoresces because electrons loose energy when they go to a lower energy state within an atom or combine with an ionized atom. a reflection nebula is a cloud of cool gas and dust which only reflects light from nearby stars. a dark nebula is a cloud of cool gas and dust which only obscures the light from more distant light sources. it does not emit or reflect any light.

read this:
http://en.wikipedia.org/wiki/Nebula

Answer 2

The other answers here are generally correct about what is called a "nebula" today. It is easily looked up in a dictionary.

However, the name Nebula was originally used by early astronomers to describe "Stars" or Planets" that they just could not get into focus, these objects would not focus to a clear point with their telescopes. They were just "nebulous" fuzzy white spots in the view, hard as they tried these nebulous objects would not be focused.
Of course now we know that those nebula's are Not single Stars or planets. They actually Galaxies of millions stars , Plasma clouds, clusters of gas around gravitation wells in space at vast distances .
So: The name stuck, even though the objects that the name refers to is not so "Nebulous" anymore.

HTH
Yours: Grumpy

Answer 3

A Nebula is a Vast Mass of Interstellar Gas. The Orion Nebula is a good one to look at. It's the gas and dust that was thrown off into space from a supernova explosion.(The violent death or a previous star.) It's also the stellar nursery where new stars are born. The gas and dust coalesce (come together) at the densest part due to gravity. When it's compressed enough for nuclear fusion to start, a star is born. M45 or the Pleides cluster is another cool one to look at. Blue young stars with blue gas clouds surrounding them. You and I were once part of a Nebula floating in space until the sun and solar system were born. YES...we were also once part of another Star. Cool...huh?

Answer 4

A Nebula is a cloudy object composed of gas and dust

There are different types
A Nebula that glows with its own light is called an emission nebula

while one illuminated by the starlight of nearby bright stars is a reflection nebula.

A cloud of dust which blocks light from star fields or bright nebulae beyond it is called a dark nebula.

Answer 5

It is a interstellar cloud of dust and cas that forms stars and sometimes even small bodies such as asteroids and comets.

Our good friends at Wikipedia say:
A nebula (Latin: "mist"; pl. nebulae or nebulæ, with ligature) is an interstellar cloud of dust, gas and plasma. Originally nebula was a general name for any extended astronomical object, including galaxies beyond the Milky Way (some examples of the older usage survive; for example, the Andromeda Galaxy is sometimes referred to as the Andromeda Nebula).

Answer 6

A nebula (Latin: "mist"; pl. nebulae or nebulæ, with ligature) is an interstellar cloud of dust, gas and plasma. Originally nebula was a general name for any extended astronomical object, including galaxies beyond the Milky Way (some examples of the older usage survive; for example, the Andromeda Galaxy is sometimes referred to as the Andromeda Nebula).

More at:
http://en.wikipedia.org/wiki/Nebula

Answer 7

a nebula is a collection of gases that usually run for millions of miles (sometimes even light years); the gases can vary in molecular makeup, which in turn affect what color we see them as. It is common for a nebula to form into a star. Our own sun was most likely a nebula to start off with back billions of years ago.

Answer 8

A nebula is a diffuse mass of interstellar star dust or gas or both, visible as luminous patches or areas of darkness depending on the way the mass that absorbs or reflects incident radiation.
My words: Nebulas are the collectings of the explosions or stars gathered in a clump!!!

Answer 9

A vast 'cloud' of dust and gas light-years across.

Sometimes gravity and the pressure from a nearby star or nova cause parts of it to collapse to form a new star & planets.

Answer 10

Gas from an exploded star and Gas of a star forming region. its all part of the cycle of the univers. Star forms star explodes and creates more stars