How does a star be born, live, and die?
104087
Have a look here,\nhttp://outreach.physics.utah.edu/labs/star_life/starlife_main.html
866857
There is no fire on the sun.  Our star is converting hydrogen into helium (which is nuclear fusion and thus creates heat) because it is so massive that the atoms its made from are being compressed by its own gravity.\n\nEventually, it will run out of fuel and stop "burning" all together, becoming a white dwarf, then a black one.\n\nLarger stars will explode and disperse their materials (the things you and I are made of) across the universe.  The largest will become black holes and try to fix the mess created by the others.
1138397
A star produces atoms in nuclear atomic chemical fusion or fission reactions.\nThe lifetime of a star takes fusion:\n3x4He > 12 C\n4 He + 12 C > 16 O plus 2x12 C > 20 Ne + 4 He\n56 Fe = Iron\n(4 He + 12 C = 16 O)+(2x12 C = 20 Ne + 4 He)_20 Ne + 4 He + 2x16 O\n= 56 Fe\nAs Iron consists to the sun's sunspots now for a magnetic field or liquid Iron of 5,000*C this gives the impression it is black against an even more hot and brighter gassy nuclear background.\nBut when the sun begins too end it's life the fusion reaches oxygen and then reaches Iron (Fe) and Beryllium (Be).\nAs the sun is completely filled with Be and Fe at the core. As metal absorbs energy and nuclear and gas forces out then the absorb from the metal core and as energy is released from the outer layers the star is unstable and is formed as a variable. The outer layers are swapped with the inners and the new outer layers are pushed off and out to a red giant until the core revs and the red giant keeps size for a while until a new process begins and the new inner layers of Oxygen from the old outer layers and the Oxygen keeps the red giant pushed out to size and then the whole star is cast as gas/plasma Iron and the star's power, heat and energy accelerates the star and with Oxygen inside, the explosion is created and a new atom is created, Gold.\nThe minerals create stars from 116 elementary chemicals.\nThe stars are made in the nebulae and new stars are made and so are planets. Thus the planets and stars create life from their chemicals and their chemicals come from the supernova.
193159
A star is basically a giant hydrogen bomb. It sits in space for billions of years fusing hydrogen into helium, creating loads of light and heat, among other things.\n\nA planet orbits a star, and is just a piece of matter that does not perform nuclear fusion. Some of them are rocky balls (like the Earth, or Mars), while some of them are giant balls of gas (like Jupiter, or Saturn).\n\nEDIT: fungusbrains1, planets twinkle too. They don't produce their own light, but they reflect light from the Sun. Any cosmic object whose light rays pass through the atmosphere twinkles.
1082193
Every star may be different.  100,000 years to even 1billion years.
1118173
Birth and death of stars is an interesting subject, IMO.\n\nHere are some starting points:\n\nhttp://en.wikipedia.org/wiki/Star\nhttp://en.wikipedia.org/wiki/Hertzsprung-Russell_diagram\nhttp://en.wikipedia.org/wiki/Supernova\nhttp://aspire.cosmic-ray.org/labs/star_life/starlife_main.html\nhttp://www.windows.ucar.edu/sun/Solar_interior/Nuclear_Reactions/Fusion/Fusion_in_stars/star_life.html
1047146
Before I answer this, you need to know what gravity is.  Gravity is the attractive force between two bodies that pulls them together (like you and the earth).  If there was no gravity, you would fly off of earth.\n\nA star has a life cycle, just like nearly anything else in this universe.  It has a growing phase where it gets bigger and a shrinking phase (the latter part of the star's life).  At the last point of its life, IF and only if it is of sufficient mass (it has got to be really really heavy), it will have so much gravity that it will pull itself in to its center.  At this point, imagine something that has the mass off 1000 times our sun but the size of a pin point (just for visualization, I know).  Something of that dimension has a gravity that is soooo intense, that absolutely nothing can escape.  If a ship went by the black hole, it would be sucked in by the black hole's gravity and crushed to the size of a pinpoint.  If a comet went by, same idea.  If a light ray (which is consisting of particles that act like a wave) went by a black hole, even the particles of the light ray would be sucked into the black hole.  Normally nothing can bend a light way.  However; if a light ray passes a black hole, the black hole will suck it in.
667822
First of all, no life forms can live on a star.  A star will vaporize them in seconds!  The Sun is a star, do we live on the Sun?  No, we live on a planet that rotates the Sun.\n\nSo, what scientists think is that there may be a planet that has life on it that's orbiting Zeta Reticuli.  Maybe it's because the star itself is very similar to the Sun, or they discovered a inhabitable planet.
522759
To Answer the First part:\n\nThe life of a star is a continual struggle between the two forces of GRAVITY and NUCLEAR ENERGY. \nThe star’s self gravity or weight tries to compress the star into a smaller sphere of gas. But when a gas is compressed it gets hot, and in the core of a star the gas gets so hot (10 million Kelvins or more) that nuclear reactions occur. In a star like the Sun the nuclear reactions release more energy each second than one billion hydrogen bombs. As this energy works its way out of the star it balances the star’s self-gravity. For most of a star’s life an equilibrium is maintained between self gravity and energy.\n\nPSS Part 2\n\nNot sure what they want here. Since the "young star" is formed from the older star dust, it would have a higher proportion of heavier elements (like Iron and Silicon), since those elements would have been created in the older stars. A new protostar would never have been exposed to these heavier elements, so it would be still Hydrogen and Helium.
551989
Stars spend most of their life fusing hydrogen to helium.  As a star gets near the end of its life it starts to fuse Helium into heavier elements going up to Carbon, Oxygen, Silicon, etc (taking progressively less time to fuse each of them).\n\nEventually the star will have an Iron core but while fusing elements lighter than Iron results in an energy release trying to fuse Iron into something heavier requires energy and so the fusion reaction can not proceed any further.\n\nNow throughout the life a star the star is in a hydrostatic equilibrium between gravity pulling the star together and the radiation pressure from the nuclear fusion pushing the star apart, with the fusion reaction stopping the gravity wins and the star collapses.\n\nThe sudden collapse causes the core to be crushed to very high density at which point protons and electrons combine to form a neutron and a neutrino according to p + e -> n + ν with the neutrino escaping (the neutrinos carry most of the energy).\n\nThe core of the star is now very small and the outer layers fall in and bounce off which is what causes the explosion.\n\nIt takes a couple of hours for the outer layers of the star to actually blow apart (which is what we'd see) so the first evidence that a supernova has occured is the neutrino burst.
786267
It depends on the mass of the star in question. For example, a star is born, it grows old, it gets larger (Red giant stage) and it dies. Depending on its mass and newly discovered turbulence inside a star before collapse, it will either go supernova and create a planetary nebula and reduce to a white dwarf, or go supernova, continue to collapse and turn into a black hole. It all depends on the mass of the star, and the amount and directionality of the turbulence inside the star's core.
110827
Considering that the vast majority of stars in the universe are small M type stars I would say that the average life span is 1 trillion years (M type stars can live for 3 trillion years)... The sun is a G2 V type star and will not live that long. It has a few billion years left on the main sequence. After that it will begin to expand and turn into a red giant. After another billion years or so its outer layers will just fizzle out into space leaving a white dwarf. So the total life span of the sun is about 10 billion years.
534669
After a star dies, there is still some residual heat left over. That heat makes the star (white dwarf or neutron star) glow, even though it is not producing any energy. Eventually, the star cools off and does indeed simply become a hunk of ash, which we call a "black dwarf." \n\npeace
471954
Greetings,\n\nI would imagine they both could be depending on the size, age, and life cycle of the particular star.\n\n-matt
967583
The other answers regarding star counts are accurate.  In fact, just like people, stars are dying and being born all over the universe.  Therefore an exact count would require omnicient overisght - there is no way a human being could know how many stars exist, are dying, and being born at one time.  \n\nWhile the universe has been thought to be infinite, or finite but really, really big, I like to conisder it finite with infinite ability for expansion.  Of course, based on its current expansion rate, the universe will eventually begin to collapse.
4783
Supernova is formed during the death of stars; large stars and super-large stars. Star dies when nuclear fusion has completed and the core of star will get smaller and smaller. A lot of heat is generated and will heat up the outermost layer of the star. \n\nHydrogen within the layer starts to burn and the stars expands. The star will appear red and are called red giant. Furhter heat loss will cause the stars to collapse because the gravitational force becomes the strongest force. It pulls the star inwards.\n\nIf the red giant is big enough, it will contract so quickly a big explosion called "supernova" will occur.\n\nIt's extremely bright and viewable during daylight. The result, a neutron star if the original star is a large star.\n\nIf it's a super-large star, a black hole will be formed. It's called that because no light can escape it including any matter.\n\nReview other answers about black hole for more details. From what I know, a black hole consumes anything for a long term but it is slowly, very slowly dispersing itself. If you want to wait for a black hole to vanish, you will probably have to wait a million years for it to vanish or you just have to find the best one; the oldest black hole.
559169
Where new stars are being born.