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Much of the conversation at the Strobel table revolved around teaching and the physical sciences, which was exciting for two empty-nest STEM teachers.
Days before high school students arrive on campus, my wife wonders what she’ll do with her science students, who won’t get their textbooks and Chromebooks until the fifth day of the semester.
She decided to do a pen and paper exercise on the periodic table. I propose to associate astronomy with “the connection of the universe to the elements”.
The periodic table is a graphical representation of the different types of atoms in the universe, such as hydrogen, helium, carbon, oxygen, iron, uranium, and more. Each type of atom known as an “element” has unique chemical properties.
There are 92 naturally occurring elements in the universe, and we have synthesized dozens more in our high-energy laboratory.
Every atom has two basic parts: a central, massive nucleus of protons and neutrons, and a cloud of low-mass electrons that orbit the nucleus. Much chemistry relies on the arrangement of outer electrons, so the periodic table arranges elements in groups with similar outer electron configurations, increasing the total number of electrons from left to right and top to bottom.
Since the number of positively charged protons matches the number of negatively charged electrons in neutral atoms, the number of protons in the periodic table increases with the number of electrons. Neutrons go all the way and help hold atomic nuclei together, so most chemicals ignore neutrons.
The cosmic connection emerges when talking about where atoms originally came from. Chemists often say that different materials are created by different types of chemical reactions, such as when carbon dioxide and water react with the energy of sunlight to produce sugar and oxygen in a process we call photosynthesis, or when coal or oil is burned. when carbon dioxide is produced.
Snobbish astronomers and nuclear physicists scoff at “creation” and say chemical reactions “just scramble atoms.” The number of different types of atoms (elements) in a chemical reaction remains the same, but the way in which the various elements are connected or bonded to each other changes in a chemical reaction. However, where did the individual atoms themselves come from?
A great deal of science has led us to discover that all atoms on Earth, planets, moons, etc. come from cosmic processes, most of which are related to stars. Most hydrogen atoms have a proton in their nucleus and were created in the first microseconds after the universe began to expand (the Big Bang), when the universe was very hot and dense. Much of the helium in the universe was created in the first few minutes after expansion began, when some of the hydrogen was smashed together in a process called nuclear fusion, similar to what happens now in the cores of stars like the sun.
Through hydrogen fusion, four hydrogen nuclei — four protons — are smashed together to form a helium nucleus, which has two protons and two neutrons. It turns out that the total mass of the helium nuclei is less than the total mass of the four original protons. The mass lost in nuclear fusion is converted into energy – light! That’s what makes the stars shine. Stars are now slowly increasing the amount of helium in the universe.
Nuclear fusion requires extremely high temperatures and densities. As stars get older, they run out of hydrogen to fuse in their cores, which are filled with helium. The core is compressed and heated enough to fuse helium to make heavier elements such as lithium, carbon, oxygen, silicon and iron. The more massive a star is, the more types of elements it can make, because higher temperatures and densities are required to produce nuclei with more protons.
Explosive stellar events called supernovae can produce many even heavier elements, such as nickel, copper, zinc, and more, through ultrafast nuclear fusion processes lasting only a few minutes. Supernovas occur when very massive stars die and their cores suddenly collapse, or when already dead low-mass stars called white dwarfs in binary systems absorb too much gas from their nearby companions. It turns out that the cores of high-mass death stars called neutron stars also briefly fuse when they collide with other neutron stars. Most of the gold and uranium in the universe comes from here.
Our theory of producing all the different elements from nuclear fusion correctly predicts the observed abundances of all naturally occurring heavy elements found everywhere in the universe. We now understand why some elements like carbon, oxygen, silicon and iron are common, while the heaviest elements like gold, mercury and uranium are so rare.
To create a planet like Earth (and life on such a planet), enough heavy elements had to be created in previous generations of stars and then concentrated in interstellar clouds, gathering in sizeable chunks around the forming star. There must be a “lag” between the beginning of the universe and the beginning of life.
Dark Sky Festival is coming
Put the Dark Sky Festivals in Sequoia National Park and Kings National Park on September 24th on your calendar.
There will be speeches and star parties. The Kern Astronomical Society will have many telescopes for people to use under really dark skies.
Contributing columnist Nick Strobel is director of the William M. Thomas Planetarium at Bakersfield College and author of the award-winning website Astronomy Notes Network.
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