Physics professor directs attention to universe
“May the stars always shine brightly for you.”
These words, inscribed by Berniece Williams Foley to 5-year-old Dan McIntosh in her book, Star Stories, set his gaze permanently on the heavens.
McIntosh’s parents – one a professor – further encouraged his scientific bent by such things as field trips, a visit to the Smithsonian and buying a Time-Life science book series.
Another factor was McIntosh’s paternal grandfather, an aerospace engineer. In McIntosh’s estimation, this kind of home atmosphere – where learning, curiosity and good study habits are extolled – will produce a fearless student ready to tackle any discipline.
Even spiny, clawed, toothy dinosaurs were no match for the inquisitive McIntosh. Of his typical child’s love-hate relationship with these ancient behemoths, McIntosh said he was more attracted and fascinated than scared.
It’s all physics
As Assistant Professor of Physics, McIntosh encourages students in his inaptly-named Physics 150 class to find meaning in the bright lights of the universe. His class is designed for the non-scientist who needs to fulfill a science requirement for a degree. He acknowledges that some students are reluctant to take a science class but consider astronomy a friendlier subject. Still, in typical introductory astronomy courses, students are confronted with as many new words as in a foreign language. McIntosh favors learning new concepts over new words.
McIntosh believes that math anxiety and other academic fears are the result of teachers communicating their own apprehensions, so he does all he can to dispel these students’ dread of math or science. He explains to his students that a lot of life follows the laws of physics – such as sticking on Mother Earth instead of floating away. Furthermore, he eliminated the textbook in favor of the workbook.
“The historic learning model is lecturing, but studies indicate that students retain more from doing than from listening. I can tell them a principle, or they can discover a principle by conducting an experiment. It’s easy to predict which one they will recall.”
Light tells the story
McIntosh’s scholarly interest is on the building blocks of the universe – the galaxies. Starlight is the roadmap, allowing one to learn a star’s past by examining the light it emanates that reaches us in as little as eight minutes (from our own sun) or much longer. The light we receive tonight from our neighbor galaxy and good friend Andromeda was emitted two million years ago.
With our sun as a yardstick of sorts, McIntosh and other astronomers observe the birth, life, mass, activity and death of the stars making up each galaxy. Orion is known in astronomy circles as a big stellar nursery, giving “birth” to at least one new star every year. The bigger the star, like those 100 times more massive than our sun, the more violent the end – a supernova. Comparing many galaxies at different distances reveals that the universe has changed over its lifetime.
McIntosh is particularly interested in the gravitational encounters and resulting mergers among galaxies. A common misconception is that any intersection of galaxies must of necessity result in the destruction and chaos of individual stars. Not so, said McIntosh.
“It makes about as much sense to worry about that as it does to worry about something happening in California affecting you while you are in Virginia,” he said. “There is so much room that it is almost mathematically impossible for one body to hit another.”
The universe follows the laws of physics, and students quickly come to appreciate just how much science influences our day-to-day existence.
McIntosh’s quick synopsis of “big bang”
The universe is really big.
In the beginning, everything in it was very small – think of particles. As these particles cooled over time, they began to slow down and coalesce into larger structures. According to McIntosh, shortly after the Big Bang light “decoupled from matter” and began traveling. This light tells us about the universe before there were stars.
Thanks to gravity, galaxies sometimes become “bound.” They are close enough and exert enough pull to draw closer and finally intersect, resulting in a merger. Independently, each galaxy is normally shaped like our Milky Way, flat and disc-like. When they merge, the new galaxy has a spheroid form much like a basketball or football.
Astronomers fall into two categories: observers – like McIntosh – and theorists.
“We get the data,” said McIntosh. “Our job is like gathering population demographics, but on galaxies. We look at high-energy blue stars (hotter ones), less energetic red stars (cooler but by no means cool), and interactions. We pass along our findings to the theorists, who create and test models. Those are shared with us, guiding our next area of observation.”
“Big hot stars live fast and die young,” said McIntosh. Much like Hollywood.