what EXACTLY is a nebula. all our teacher told us it that it was a place where stars are born......?

Answer 1

A nebula (..plural is nebulae) is a vast collection of various gases and dust in space. Most of the material in nebulae come from old stars that have exploded and thrown their gassy material into space. New stars and planets can and do form within these nebulae. Our own solar system began this way. This website has photograph of a nebula in which you can see the new stars beginning their lives ==>http://apod.nasa.gov/apod/ap060119.html

Answer 2

A nebula is a cloud of dust and gas in interstellar space. At one time, any fuzzy object in the sky was called a nebula, but now we know that some of the objects formerly called nebulae are galaxies or star clusters.

Gravity causes the material in these clouds to clump together, and if the clumps become dense enough, stars are born. The Lagoon Nebula (M8 ) is a good example of a nebula where stars are forming. You can see the Lagoon with the naked eye in a dark sky - it's a hazy patch just across the Milky Way from the spout of the Sagittarius "teapot". Nebulae like M8 glow because their gasses are energized by light from extremely hot, young stars that have been born there. There are also dark nebulae (e.g. Cone Nebula ), which can be seen only because they block the stars behind them. These nebulae may contain stars also, but are too thick to let the light out.

Other nebulae are the remains of dead stars. This material may eventually get swept up into a star-forming region - all stars now show traces of heavier elements formed in earlier stars. The Crab Nebula (M1) is the remnant of a supernova (an exploding star). Planetary nebulae (e.g. the Ring Nebula, M57) are the remnants of stars that died more peaceful deaths and turned into white dwarfs.

Answer 3

Nebula must be Latin for fuzzy or something. An astronomer, Charles Messier (1730-1817) was searching for comets when he found these fuzzy "nebulous" things and the name stuck. Messier spotted over 100 of these things in the sky. This caused a certain amount of confusion, because some patches of light were other galaxies, others were clouds, like the Orion Nebula. Still others were remants of a supernova, like the Crab Nebula. So, scientists nowadays are very precise how they classify a particular "nebula." Reflection Nebulae and emission nebulae are clouds of dust within our own galaxy, either emitting light by their gases being ionized from starlight, or reflecting it. Both types are often seen together and are sometimes both referred to as diffuse nebulae. Dark Nebulae are clouds of dust which are simply blocking the light from whatever is behind. They are physically very similar to reflection nebulae; they look different only because of the geometry of the light source, the cloud and the Earth. A typical diffuse nebula is a few hundred light-years across. Planetary Nebulae are shells of gas thrown out by some stars near the end of their lives. Our Sun will probably produce a planetary nebula in about 5 billion years. They have nothing at all to do with planets; the terminology was invented because they often look a little like planets in small telescopes. A typical planetary nebula is less than one light-year across. However, a new sun is also surrounded by such a shell, and planets do form within, as evidenced by our own solar system.

Answer 4

It is a large formation of gas and dust in interstellar space. They are usually comprised of hydrogen although other gasses (helium, etc) could also be present. A nebula is also illuminated by nearby stars that give them a colored glow. This is caused by ionization of the gas by high energy radiation from the nearby stars.

They are called "the birthplace of stars" because gravitational forces can cause the gas to begin to collect in one mass. If the mass of hydrogen becomes dense enough and massive enough, internal heating will initiate a fusion reaction that can self sustain - thus "a star is born".

I don't know the exact stats but not all nebulas are star forming regions. Only some are, as the gravitational and other dynamic forces have to be exactly right for stars to form.

Also there are many conglomerations of gas and dust that are not visible because they do not have local stars ionizing the gas and or "backlighting" them. These are invisible to us and are part of the mass in the universe known as "dark matter."

Answer 5

"Nebula" is a word with a long and complex history. The oldest derivation seems to be Hebrew "Nephr." There is also a Greek stem "nephos," meaning "cloud" or "cloudy."

Others have answered the question of the nature of a nebula quite effectively. The widely-accepted idea that stars and galaxies and solar systems "condensed" out of nebluae is called the "nebular hypothesis." It is supported by much evidence.

The word "nebula" is also used in medicine to refer to small, fluffy-looking" bodies that appear to float in the fluid of the eye.

Answer 6

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.

stars form in nebulae. emission nebulae fluoresce because the ultra-violet light from nearby stars ionizes the hydrogen, and when the electrons loose the energy they got from the uv light, they emit visible light and invisible light. the nearby stars are young and massive and have just formed so they are still near the nebula in which they formed. they look blue because they are so hot.

look here:
http://en.wikipedia.org/wiki/Nebula
http://en.wikipedia.org/wiki/Black_body

Answer 7

A nebula is often referred to as the birth place of stars, is an area spanning many millions of light years and is comprised of gasses, dust and atoms necessary for star evolution.

Answer 8

A picture is worth a thousand words go the the Hubble site (search Hubble telescope) and look at the pictures that they have labeled as nebula (I recommend the Horse head nebula )
They are mostly just large areas of hydrogen gas and such!

Answer 9

its a place where stars are born and also the leftovers from a super explosion of a star