Look-UP

by Mitchell Tester, College Student

Q’s

For this month, I would like to take a break from the two-part “Time” series I started last month. “Q’s” will be a new edition I do occasionally, where I have one or more people send in a question or questions, and I answer them. Of course, due to this being the first one, I will be using my friend Aiyana’s question. They asked the following: What is a star?

This is one of the most fascinating topics I learned about when I started getting into astronomy and astrophysics. A star is actually quite similar to our own home, our neighboring planets, or most objects out there in the universe. Most known object creations in the universe are dictated by similar celestial makeup. This means the planets, asteroids, moons, and even black holes. To answer Aiyana’s question, let us use two of the above-mentioned celestial objects and describe how they start and how they are eventually made: planets and black holes. These will solidify the similarity that the stars share with everything else in the universe. Astronomy teaches us everything is connected.

Before any notable object is made in space past the Big Bang, there sit massive clouds of gas and dust at the very start of it. These dust clouds happen due to matter’s natural attraction to other matter; this is what we call gravity. Gravity, within the dust cloud, will pull these particles as they pass. Gravity will also cause the matter in this disk to pull inward.

This spinning creates the above-mentioned disk, allowing for matter to exist not only in the center but elsewhere due to pockets of gas and dust existing before the spinning took place. What is created at the center will be discussed later. The outer pockets continue to accrete more and more matter, eventually forming solid cores, named protoplanets. Simply put, matter in the cloud got so close that it started to form the elements that make up what it is now.

Take our home in our solar system, for example. At 93 million miles from the center (1 astronomical unit) sits our home, Earth. Earth was once just a collection of dust and gas, but throughout time of it spinning and spinning with the protoplanetary disk, it formed a solid core, named a protoplanet, and then formed all the other layers that make it up. Simply put, matter in the cloud got so close that it started to form the elements that make up what it is now.

Stellar-mass black holes are created from dying stars, while other black hole types, such as supermassive black holes, were created in the centers of protogalactic disks, massive disks that create the galaxies of the universe. Let us focus, though, on stellar-mass black holes (ones that come from stars).

Stars come in all sizes. Our star, the Sun, is about average in size. An average star, such as our own, will never become a black hole; it’s simply just too small. However, for stars nine times the mass of our own and larger, when that star eventually dies, the core will collapse and result in a supernova explosion, leaving just the core of the former star. A core that is thousands of times denser than any star.

Stars, where stellar-mass black holes eventually result from, come from a spinning disk of matter just as our Earth did, just as the supermassive black holes came from their galaxies’ spinning disks. At the center of protoplanetary disks, though, is what eventually creates stars. The sheer amount of matter at the center, compared to the smaller pockets on the outer parts of the disk, is what allows stars to form. So, to put it simply, planets and stars are made up of the same celestial ingredients; just one simply has more matter. This collection of matter, apart from the size difference, allows for nuclear fusion. Nuclear fusion is what results in a star creating energy: the energy that is created by the immense heat and pressure in the core, constantly fusing hydrogen into helium. The light that guides our way during the day and what allows life itself to exist as we know it.

A star is a celestial object that has a mass of approximately 25,000 times the mass of the Earth. It is as simple as that.

I hope you all enjoyed the first edition of “Q’s.” If any readers of my column have a question they would like for me to answer and make its way to the next edition of “Q’s,” I have made an email for just that reason. Email me at lookupcolumncb@gmail.com. Please feel free to ask questions, tell your own astronomy stories, share your own astronomy pictures, or even tell me how I am a lousy writer and that I shouldn’t quit my day job. Thank you for reading everyone, and tune in next month for Time: Part II.