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Founded January 1970
Julian date: 2457726.16
"I went to a restaurant that serves 'breakfast at any time'. So I ordered French Toast during the Renaissance."
-Steven Wright
THE DAILY ASTRONOMER
Tuesday, December 6, 2016
Fantastical Pandoras
We must be careful whenever we are tempted to dismiss a question as absurd or an idea as "mad." Seemingly silly questions or preposterous notions have often resulted in great advances in our understanding of this wholly strange Universe in which we have found ourselves. For instance, Special Relativity, one of the 20th century greatest achievements, started in part when Einstein asked, " How would a light beam appear to an observer capable to running alongside it at the same speed?"
During this dip into Pandora's Jar, we encounter two questions that might seem outlandish to the point of being fantastical. However, each question afforded us the opportunity to look at the world in a different way. Any question that does that is certainly worth asking.
PANDORA PARCHMENT # 9:
"Ok, this is the most narcissistic question you have probably ever received. I know that astronomers have 'found' dark matter by seeing how that matter affects the visible stars. The more matter in the galaxy, the faster the stars move. Well, I was wondering...when I die, the galaxy will have less matter and therefore will my death cause the galaxy to turn more slowly?" -I Anonymous
Greetings!
Yes, it is true that a galaxy's rotation rate, or, more precisely, the velocities of the stars within the galaxy, are related to the galaxy's mass. The loss of any material within the galaxy will reduce its mass and could decrease the stellar velocities. However, the material comprising a human remains within the galaxy even after the human's death. In fact, the particles comprising your body existed for billions of years before your birth and will persist for billions of years more after your death. Our constituent matter remains within the galaxy, albeit in different forms
All the same, let's assume that some renegade human teleports out of the Milky Way Galaxy to a distant point. Now, the Milky Way has indeed lost some material. However, the loss is certainly negligible and wouldn't affect the galaxy rotation at all. Even if every human grew tired of this galaxy and emigrated to another galaxy, our home galaxy -or, what was our home galaxy- wouldn't be affected at all. You realize that the mass of all the humans who have ever lived and are now living is equal to about one cubic centimeter of neutron star material. We don't add much heft to this barred spiral galaxy we call home.
PANDORA PARCHMENT # 10:
"Will all the powder on a doughnut rise off the doughnut in zero gravity?"
-Radio listener
Hello!
That is actually a good question. To answer this question, we're going to pretend that an astronaut aboard the International Space Station is about to help herself to a beautiful powered doughnut. Before engorging, she snaps the doughnut to shake off some of the powder. What happens? Well, as she is in micro-gravity, the powder doesn't just fall back onto the doughut as would happen on Earth. The displaced powder moves away from the doughnut and only stops moving due to collisions with the air within the station. However, the powder already on the doughnut will remain there because it is trapped on the doughnut's surface in the many little peaks and valleys that are hidden within almost all solid objects. (When you slide a book across a desk, it will eventually come to a stop because the irregularities within the book's surface and the desk's surface will rub against each other, causing the book to lose energy and eventually come to a stop. This is a result of kinetic friction...the friction of motion.)
Gorgeous powdered doughnut. If floating in
micro-gravity, the powder would remain on the doughut
unless something shakes it off. Image by dreamstime.com
Even in micro-gravity, the powder particles won't just lift off the doughnut's surface. Some force would have to raise the powder from the surface, No object, be it a grain of sugar or a baseball, can move on its own volition Some force must be applied to it in order to impart motion on it if stationary or to impede its motion if it is moving. The astronaut who shakes the doughnut imparts a force on the doughnut and causes some of the powder to move off the doughnut surface. It won't do that on its own.
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COMING FEBRUARY 2017 TO THE SOUTHWORTH PLANETARIUM
A full dome theme park adventure!
Rollercoasters and other thrill rides through the solar system.
Rollercoasters and other thrill rides through the solar system.
Showings each day during February school vacation week
Feb 20 - 24, 2016
Consult www.usm.maine.edu/planet for more information!
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© 2016 Edward Gleason