From Gas Cloud To Apocalyptic Fiery Ball Back To Gas Cloud: The Fascinating Life Of A Star
Space is weird; a lot of people forget that. And one of the most abnormal things in space are stars: they’re literally flaming balls of plasma that mash atoms together so hard that they expel unfathomable amounts of energy. For example, the Sun, which is an average-sized run-of-the-mill star, produces 384.6 septillion Joules of energy every second! That’s a 4 with 26 zeros behind it! To put that into perspective, you could power about 5 x 10²⁴ lightbulbs every second. To put that into perspective, you could power all the street lamps in New York City 200 billion billion times over, every second.
Without a doubt, stars are a key part of the universe, and to understand them, we need to understand their life cycle, from babyhood to child-bearing and finally to decrepitude and death.
Birth And Childhood
(Around 10 Million Years)
Meet Sirius. He’s an average-sized star in the Orion Constellation. Orion is supposed to be a warrior giant, and Sirius is his loyal dog and hunting partner, or at least that’s what the ancient Greeks saw.
Like most of his star-studded brethren, Sirius’ maternity ward was a gas cloud, called a nebula. In Sirius’ case, his nebula was the Sirius nebula (yeah, astronomers get lazy and there are only so many Greek and Roman mythical creatures and an infinite amount of stars and physical phenomena). Irregularities occur in nebulae like this one, and the gas begins to clump up. Eventually, one clump becomes so huge that it collapses in on itself, forming a disc, and the center heats up. This is our “newborn”, the proto-star. Sometimes, some of the matter breaks up and forms another proto-star, and those two revolve around each other (this is called a binary system), which is what happened with Sirius: there are actually 2 Siriuses, Sirius A and his (much smaller and practically invisible) twin Sirius B.
Adulthood
(Varies from star to star, 1 billion years for our friend Sirius A)
Just as some people are lucky enough to have kids, some stars have children too. Sometimes, the leftover material from the proto-star nebula forms smaller clumps that grow to become proto-planets and then planets (this means that everything on Earth, including organic beings, is made up of star material. We are quite literally star-stuff) after everything cools down. This is what happened for our star, which we ever so self-centeredly call THE Sun. Sadly, Sirius A is destined to live alone (except for his tiny twin), for the planets never formed.
After Sirius A has finished settling down and became a full-fledged man/star, it became time to get a job, and like every other star, his job is to become a nuclear plant. In Sirius A’s core, Hydrogen atoms are fused to become Helium. This process generates energy, which is expelled in the forms of heat and light, which give the star enough pressure to not collapse on itself. Furthermore, they either give heat and life (or death) to planets or in Sirius A-and-many-other-stars’ case, just give us pretty views on clear nights.
Old Age, Retirement, and Death
After all the Hydrogen in Sirius A is used up and converted to Helium, it’s time to hang up the work boots. However, some bigger stars’ nuclear fusion capabilities don’t stop there, they continue to convert Helium to Carbon, to Neon, to Magnesium, to Sodium, and so on, until Iron. However, this means that these stars get burnt out and die faster than smaller stars (lesson learned: don’t overwork yourself).
Apparently, whatever government that rules stars doesn’t believe in senior citizen rights. In the case of Sirius A, his core begins to collapse after using up all the Hydrogen, which causes the outer layers to bloat up and turn it into a red giant. Then, nuclear fusion happens very rapidly until, like the large stars, Iron forms, and the star can’t take the huge mass anymore, and the star will explode, making a supernova, an explosion of light and heavy metal dust, releasing gigantic amounts of energy, more than what Sirius A has generated his whole life. The protons and electrons will become neutrons, and Sirius A will become a neutron star, an unfathomably dense object that packs the mass of an entire star into a sphere the size of a large city.
However, this isn’t what happens to all stars. Sirius A’s larger cousins will become black holes because they’re packing more mass into a smaller space, so the remnants of such a star have such a large gravitational pull that they swallow themselves and everything that comes close to them. But, Sirius A’s smaller cousins become white dwarves, where the star isn’t dense enough to turn all the sub-atomic particles into neutrons.
Sure, Sirius A might live alone in the dark, lifeless empty space for a billion years and then die a painful death in a spectacular explosion, but at least we’ll be here, to study, observe, be amazed, and be inspired by his beauty. Oh, and Sirius B will be there too.
Sources
https://www.pbs.org/video/crash-course-astronomy-31/ (Plait, P. (2016, March 20). High Mass Stars: Crash Course Astronomy #31. Retrieved July 25, 2020, from https://www.pbs.org/video/crash-course-astronomy-31/)
https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve (Nagaraja, M. (n.d.). Stars. Retrieved July 25, 2020, from https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve)
https://damoosemafia-starslife.weebly.com/prediction-of-death.html (Sirius A- Prediction of Death. (n.d.). Retrieved July 25, 2020, from https://damoosemafia-starslife.weebly.com/prediction-of-death.html)
Salpeter, E E. “Energy Production in Stars.” Annual Review of Nuclear Science, vol. 2, no. 1, 1953, pp. 41–62., doi:10.1146/annurev.ns.02.120153.000353.