In the Delivery Room

Analyzing the process of human gestation and birth is relatively easy. Little theorizing is required because all one needs is about nine months of free time to make some direct observations.

The birth of a low-mass star, however, may consume 40 to 50 million years— obviously more time than any observer can spare. High-mass stars, as we have seen, have shorter lives and more spectacular deaths. They also appear to collapse and fall onto the main sequence more rapidly than low-mass stars.

A brown dwarf is a failed star; that is, a star in which the forces of heat and gravity reached equilibrium before the core temperature rose sufficiently to trigger nuclear fusion in the core.

While we don't have time to watch a single star go through all of the stages outlined, there are fortunately many different star formation regions in different parts of our Galaxy. Taken as a whole, these regions (in different stages of evolution) give us a more complete picture of how stars form from the matter between them.

The Least You Need to Know

V The spaces between the stars are not empty, but contain gas and dust, from which future generations of stars form.

V Dust grains in interstellar space absorb and scatter visible light, so that distant objects are reddened or not optically observable.

V Emission nebulae, or HII regions, are regions of ionized gas that occur near hot, young stars. These clouds of hydrogen absorb ultraviolet emission from the young star and re-emit the light at longer wavelengths.

V When giant molecular clouds collapse, they fragment into smaller clumps, some of which form stars.

Telescopes Mastery

Telescopes Mastery

Through this ebook, you are going to learn what you will need to know all about the telescopes that can provide a fun and rewarding hobby for you and your family!

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