Word Ladders III

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    Here we have more word ladders, this time on an astrophysical theme.

I: Using Einsteinís formula, convert mass into heat;

    We have: mass, miss, mist, list, lest, best, beat, heat.

    According to Einstein, mass and energy come to the same thing. When two nuclei combine with each other, their combined mass will miss the sum of their original masses by some small amount. In the thick, glowing mist at the center of a star many nuclei combine every second. Those reactions produce a long list of heavy nuclei, up to and including those of iron. We must take all of those reactions into account, lest we get a wrong answer when we add up all the small amounts of missing mass. The nuclear theory devised by Hans Bethe and others gives us our best calculation of the necessary figure. But for sheer simplicity, nothing can beat Einsteinís mass-energy equation. If we multiply the missing mass by the square of the speed of light, we get a number that tells us how much heat that mass has become.

II: Let interstellar dust create a star;

    We have: dust, gust, gist, list, lest, test, text, next, neat, near, sear, star.

    A vast cloud of dust and gas exists in intragalactic space. A gust of stellar wind from a nearby supernova renders it unstable and it begins to collapse. A full description of the collapse is complicated, but the gist of it tells us that the cloud heats up as it collapses and that it can only collapse fully because the dust radiates the heat, enabling the cloud to collapse further. An accounting of all the effects that occur in the collapsing cloud would make a fair list, but we need only focus on the collapse itself. We want to pay special attention to that one effect, lest we get distracted from our main concern. Once we work out the main effect we can work out the others and test them against observations. We will, of course, find some of those effects worked out for us in some appropriate text. But now the collapse has come to the next major stage in the cloudís evolution. The neat infall of dusty gas hits the cloudís center of gravity in an intense shock. Heat and pressure build up near the cloudís center and instigate thermonuclear fusion, which generates even more heat. The extra heat turns into radiation and is glown into space intensely enough to sear any object that gets too close. The cloud has become a star.

III: Describe snow on a Saturnian moon;

    We have: snow, slow, blow, blot, boot, boon, moon.

    The snow that falls near Saturn is not always made of water: it may also be made of methane or ammonia. Itís descent is slow in the weaker gravity of one of the lesser worlds. Only weak winds blow to move it around. It certainly doesnít get thick enough to blot out the distant sun. In some places only an astronautís boot has disturbed it for the first time in thousands of years. Nonetheless, its insulating properties are a boon to explorers when it is piled up over their settlements. Thus, it will make easier the exploration of that Saturnian moon.

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