How do stars come to be?

Answer 1

All stars are formed from nebulae (the plural of nebula). Nebula is a term for a cloud of gas, and stars form from gas. Stars more massive than ~ 6 solar masses are expected to supernova, stars less massive than this (like our Sun, of course) become white dwarfs. After a supernova, there may be nothing left, or there could be a remnant: either a neutron star or a blackhole. If the remnant is more massive than around 3 solar masses it will probably end up as a blackhole. Stars are smallest when they are burning hydrogen into helium, which is what stars do during most of their lifetimes. Stars in this stage are sometimes called dwarfs. There are also two other kinds of "dwarfs": white dwarfs are burned-out stars mentioned above (the Learning Center has more info on these), and brown dwarfs are stars which never accumulated enough mass to start burning hydrogen.

Answer 2

Eagleflyer has the best explanation so far. r_moulton76 was OK until he got to populations, and then he got it backwards. The Sun and other stars in the disk of our galaxy are Population I stars. This is the most recent generation of stars, as the spiral arms are where starbirth happens. Population II stars are older, and compose the spherical galactic halo. The first generation of stars, formed from the primordial material of the Big Bang, is called Population III. No Population III stars have been identified. If the numbering sequence seems backwards, it's because it was assigned before its significance relative to stellar evolution was understood.

Astronomers can tell which generation a star belongs to from the amount of heavier elements revealed in the star's spectrum. As time goes on, dying stars put more heavy elements into the interstellar gas and dust clouds. The material fro Population III stars would have been nearly pure hydrogen and helium, with a trace of beryllium.

Answer 3

Stars come to be from previous generations of stars that have exploded, leaving huge molecular clouds, 1000s of light years across, made up mostly of hydrogen, helium, carbon, beryllium, stuff like that. These huge molecular clouds (like the one in the constellation Orion, or the Eagle Nebula, to name just two) are stellar nurseries. When these clouds contract and condense through gravity, they get very dense in many points throughout the cloud. These points, or centers, keep attracting more and more matter, and as a result these centers (cores) start to heat up from all that gravitational pressure. When the temperature in these cores reaches 10 million degrees, atomic nuclei of hydrogen (protons) start slamming into other protons. This is what's known as nuclear fusion. Nuclear fusion creates a helium nucleus from four hydrogen nuclei, releasing a lot of energy in the process. A star is born! Some of the youngest stars you can see in the sky are the Pleiades (they came into being around the time the dinosaurs walked the Earth, which is very young for a star). Stars can burn for billions of years. Our sun has been fusing hydrogen to helium for about 5 billion years and has about another 5 billion years of fuel left.

Answer 4

The essential ingredient is gravity.

Within the existing universe, new stars are formed from the remnants of old stars which have gone nova. These remnants (nebulae) are vast clouds of expanding ionized gas. The particles within the cloud, however, have mass and this affects the trajectory of other particles so that they do not travel outward in a straight line. Over the course of time, they tend to clump together. Then the clumps merge, and so on. If there is enough mass left, it eventually becomes dense enough to generate fusion and a new star is born.

Sol appears to be a star that formed in this fashion, a so-called Population II star. Population I stars are extremely old and stable, of the first generation of stars that coalesced after the Big Bang (in approximately the same fashion as outlined above).

Answer 5

I'm an Astronomer so I got some good info for you at our observatory ..

To look at how stars come to be , let's check out star birth .. Nebula's are stellar nursaries .Stars are made & born from them .

I have 2 answers for you .. easy & scientific




EASY ANSWER ... ...........

The first step in the birth of a star is to wait. Dust, gas, and other materials sit around in nebulae, and wait for eons until a passing star, shockwave, or other gravitational disturbance passes through or by the nebula.

Once this happens, its gravity causes swirls and ripples. It would be like spreading marbles out on a trampoline, and then rolling a large lead ball around the edge, or through the middle. The other marbles would roll around, and clump together near the path the lead one took. It is no different in a nebula when a star passes by. To add to the marble analogy: When the marbles gather in places, the dip in the trampoline causes other marbles to accumulate in the same spot until there are just a few piles of marbles, with very few marbles in between. This process is called accretion, and causes the stars.



SCIENTIFIC ANSWER ..................

It takes 300,000 years for stable hydrogen and helium atoms to form. Gradually these atoms began to clump together into gas clouds called nebulae.

Over the course of the next 300 million years, these clouds grew. They attracted more and more atoms and so became increasingly dense and hot.
Eventually, the centres of these clouds became so hot and dense that they exploded in huge nuclear reactions. Hydrogen atoms began to fuse together and the clouds were transformed into blazing balls of fire. The first stars were born.

Stellar birth is still going on today. As you read this, stars are emerging and dying all over the Universe.

Answer 6

well when gases come together thay form into a nebula. after this gravity pushes it together until it is a big gas ball.

Answer 7

Read this weeks Time Magazine and/or Newsweek.

Answer 8

lots of funky gases (Stop poluting the AIR!!!!!!!!!!!)