Stars are Born in Batches

Where do the naturally occurring elements come from? Our universe, all of it, almost everywhere, is 99 percent hydrogen and helium, the two simplest elements. Helium, in fact, was detected by the Earthlings on the Sun before it was found on the Earth – hence its name (from Helios, one of the Greek sun gods).

But the Earth is an exception, because primordial hydrogen, only weakly bound by this planet’s comparatively feeble gravitation attraction, has by now largely escaped to space. Jupiter, with its more massive gravity, has retained at least much of its original complement of the lightest element.

Might the other chemical elements have somehow evolved from hydrogen and helium? The answer is “may be”. In fact, to balance the electrical repulsion, pieces of nuclear matter would have to be brought very close together so that the short range nuclear forces are engaged. This can happen only at very high temperatures where the particles are moving so fast that the repulsive force does not have time to act (temperatures of tens of millions of degrees).

In nature, such high temperatures and attendant high pressures are common only in the insides of the stars.

Thus stars like the Sun are born in batches, in great compressed cloud complexes such as the Orion Nebula. Seen from the outside, such clouds may seem dark and gloomy. But inside, they are brilliantly illuminated by the hot newborns stars which grow older and wander out of their nursery to seek their fortunes in the Milky Was, stellar adolescents still surrounded by tufts of glowing nebulosity, residues still gravitationally attached of their amniotic gas.

Let’s evoke a nice example: In the direction of the star Deneb, in the constellation of Cygnus the Swan, is an enormous gloving super-bubble of extremely hot gas, produced by supernova explosions, the death of stars, near the center of the bubble. At the periphery, interstellar matter is compressed by the supernova shock wave, triggering new generations of cloud collapse and star formation. In this sense, stars have parents; and, as is sometimes also true for intelligent creatures, a parent may die in the birth of the child. The Pleiades are another example.

Well, as in the families of humans, the maturing stars journey far from home, and the siblings see little of each other. Somewhere in the Milky Way Galaxy there are dozens of stars that are the brothers and sisters of the Sun, formed from the some cloud complex, some 5 billion years ago. Most of them, for all we know, are on the other side of the Milky Way.

Supernova explosions are the death of stars. Image: © Megan Jorgensen

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