So you’ve signed up for a course in astronomy. Conscious of your responsibilities as a student, and sort of interested in the sky, you read the syllabus. Under Day 4, you spot the phrase “The Life Cycle of Stars.”
“Life” cycle? Are stars alive?
Wary of the instructor possibly chortling at such a question, you keep quiet, but vigilant for an answer.
At every turn, the instructor talks as if stars are alive. She speaks of “stellar evolution,” as if whole species of stars were living up there. She speaks of “star birth,” which occurs in “stellar nurseries” where gas and dust twine together, accumulate more gas and dust, and grow to a mass that starts to create heat.
A cross section representation of the star BPM 37093, which is thought to have a diamond core. Image from Harvard-Smithsonian Center for Astrophysics
She speaks of the “lifetimes” of stars, because it turns out most stars “mature” into certain kinds of stability lasting a few million or billion years, depending on their size. Then in their “old age” (according to the prof) their bodies go through changes that for some include enormous expansion; these stars are called red giants. The “death” of some stars occurs in a spectacular explosion called a supernova, and the death of others amounts to a process of burning out and fading away. Sounds familiar.
Other weird things apparently happen to large stars, where they collapse and disappear from sight as black holes and singularities. A black hole is a region of space where a large mass, probably left over from a star explosion, has contracted to a few miles or less in diameter and its gravity is so concentrated that even photons of light can’t escape from it. Physics predicts a point, called a singularity, at which the star material has contracted so much that the contracting can’t stop — the star has shed its natural physical form and seems to disappear into itself. This does not sound very familiar unless you think about it too much, or read Buddhist sutras.
Smaller stars in their old age also shrink, and different metals, such as iron or lead, are about all that’s produced during the burnout. In some cases, though, carbon can be supercompressed in the contraction until the interior of the star becomes, essentially, a diamond. It takes billions of years to make a star a diamond.
This was just a theory born from physics equations until some years ago when astronomers found a star, BPM 37093 in the constellation Centaurus, which gives off most of the readings predicted in the equations indicating carbon compression. The core of BPM 37093 apparently is a massive diamond weighing about 10 billion trillion trillion carats. Nayutas of kotis of carats, the sutras might say.
Despite its achievement, however, BPM 37093 will not live forever. It will go the way of all the other dwarf stars before it and all those after it, and fade into the vastness of space.
The instructor stops short of using the word “achievement.” Somehow that got into your head by itself. Just like people, stars are born, live, and die, and just like stars, people shine, burn out, and disappear. Can a person become so crystalline she is essentially a diamond? (Or lead?)
Not really, right? The astronomy prof is just using metaphors. Stars don’t actually have “life cycles,” right? And human minds cannot, through the stress of prodigious energies, become “diamonds.” Right?
Dana Wilde lives in Troy. You can contact him at naturalist1@dwildepress.net. His book “Winter: Notes and Numina from the Maine Woods” is available from North Country Press. Backyard Naturalist appears the second and fourth Thursdays each month.
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