Derenda Mullins, age 12, of Visalia, California, for her question:
Can they explain the birth of a star?
The birth of a star is a stupendous event, created by cosmic forces that also govern its future destiny. Probably no two stars are identical twins with idential life stories. But certain types are very similar. The strange ones, such as pulsars, are rare. It seems that the vast majority of average stars are created in more or less the same way. We know that new stars are being born while older stars are consuming the last of their fiery fuel.
In the last couple of years, the newly discovered pulsar revealed how a normal star does not behave. Strange to say, this information helped to explain some old mysteries about how an average star does behave. This led to a new theory that suggests how the average star may be born. There is a lot of evidence to support it, but as a theory we cannot state it to be a true and proven fact.
Astronomers agree that the birth of a star requires two basic ingredients ¬enormous quantities of matter and energy. They also agree that the matter ingredient is a stupendous cosmic cloud of gaseous particles. The new theory suggests that the basic energy ingredient is gravitation. This seems odd, because in small local matters gravity is the weakest cosmic energy. However, in large astronomical matters it is the mightiest. It may be the key energy that molds a star, ignites it and governs the nuclear energy of its furnace.
On a local scale, gravity is built into every particle of matter. Each particle in a cosmic cloud has its miniscule quota. In massive suns, its strength is intensified. In all matter, it acts as a subtle pulling force, diminishing with distance as it spans throughout the universe. Gravity never ages or grows weary.
The birth of a stupendous star may begin in a small way. Here and there in the cosmic cloud, gravity attracts a few particles together. These masses have more strength to attract other particles. Gradually the hazy gases condense around a massive core. Gravity now works harder and faster with crushing force.
The spinning motion of rotation can delay the crushing fist of gravity. For reasons still unknown, the unborn star begins to rotate. This prevents its complete collapse. But enormous heat and pressure already exist in the massive core. Electrons are stripped from the crowded atoms, nuclei are crushed together. At some dramatic moment, hydrogen nuclei fuse to form helium nuclei, converting fragments of matter into nuclear energy. This nuclear fusion ignites the furnace and the star is born in a blaze of glory.
Gravity belongs to matter and so long as the matter endures it never loses its strength. A rotating star counteracts its crushing fist and may divert some of it to energize its nuclear furnace. However, these forces must be delicately balanced. Nuclear energy is extravagant and eventually burns up its fuel. Meantime, the star's gravity steadily holds it together, even after the furnace burns to a ball of cold, dead ashes.