Everyday Days of an Instructor

As an instructor I find that there are good days – days when my students remind me of why I selected my profession, and there are also bad days when small collections of specific students make me really frustrated. Most days, however, are just days where all of us are just trying to get through life. The measure of a career is ticked away in these more average days. The quality of these everyday days varies from place to place, and opinions of quality vary as one person’s pleasure is someone else’s terror. To find happiness, we must each tune our location to the lifestyle that makes us happiest on so called normal days.

Over the years, I’ve had the opportunity to work a lot of different places. The universities I’ve haunted have ranged from the Big Ten (MSU), to the Ivy League (MIT and Harvard), to the Big 12 (UT), to the unheard of (SAO), to a small state school (SIUE). My students faces have ranged in age from the 10-year old prodigy learning college-level astrophysics to the late 50s chinese immigrant working through freshmen physics toward a dreamed of PhD. The students I have worked with have ranged from students so smart and together that they can run 1500 person programs without traumatizing their grades, to students who are just trying to figure out how to just get through their next homework set. To me, the measure of my career is counted not in the number geniuses I can help loose onto the world, but rather it is counted in the number of students for whom I can make just one idea click and who I can help find their dream that they want to make reality.

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Helix hides Comets in its Core

Helix hides Comets in its Core

169140main_piaa09178-330.jpgIt is easy in astronomy to lump different objects into specific groups. At the top-most level, there are stars, galaxies, planetary systems (including asteroids and comets), and dust-bunnies interstellar and intergalactic media (clouds and nebula). Looking a bit deeper, each of these categories can be nit-picked apart into more sub-categories. For instance, stars can be divided up by energy generation mechanism, or mass, or both. But, astronomy isn’t just the study of a bunch of discrete objects that can be junked into boxes any more than plant science is the study of how a bunch of leaves that can be classified by structure. Both sciences must consider the ecology around discrete objects. Trees grow in forests in symbiosis with other plants and animals, and are both harmed and helped through these synergistic relationships. Stars too exist in rich environments, and when we study stars and their evolution we are also studying the evolution of their planetary systems and of the galaxy they live within. Until recently, it was easy to see the average star as an isolated object on a solitary journey from molecular cloud to planetary nebulae – we simply weren’t able to see anything other than the star and what isn’t seen is easily ignored. Today, however, that is all changing.

As we peer at stars in more wavelengths and in greater detail, we are beginning to find evidence of planetary systems around more and more objects.* As we witness this co-formation of stars and planets it is becoming impossible to stick stars in discrete boxes – Stars and planetary systems must be studied as a whole. This was brought home to me by a newly released Spitzer Space Telescope image of Helix nebula (above right, credit:NASA/JPL-Caltech/K. Su (Univ. of Ariz.)). This favorite object of amateur astronomers appears as a faint swirl of light through the eyepiece of a backyard telescope in a dark location. With Spitzer, it is resolved into concentric rings marking the location of a dead star. Around that dead star are the remnants of a cometary cloud.

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Three New Species Discovered in the Milky Way

Three New Species Discovered in the Milky Way

hidden.gifScientists this week have discovered three previously undiscovered species: a new species of reef lobster living off the cost of the Philippines, a new source of gamma-ray radiation associated with star forming regions, and a new class neutron star+supergiant binary found the Milky Way Galaxy. Each of these three discoveries leads it’s respective discoverers to believe there are a myriad of things still waiting to found in the oceans and outer space. In our cyinical era of “been there, done that,” it seems there is nothing new to wow the mind, but these three new critters indicate our planet and our universe still have a few surprises in store for explorers.

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Education: Some Assembly Required

Education: Some Assembly Required

While I was at Michigan State University, we had a change of president. The new guy in charge (at that time – it’s changed again since then) was M. Peter McPherson (and, as he would tell you, McPherson rhymes with person). He came from a business background, and under his guidance, students became consumers and professors became the provider of a specific good – an education. This idea of education being something that can be purchased pre-supposed that a student’s learning is directly correlated to the professor’s teaching. This is a model that doesn’t work real well. Learning is actually a collaborative journey, and like with any collaboration, success depends on what all members bring to the table. As a student, I saw the “student as a consumer” model as broken, but also as justification for expressing teenage indignation at any faculty member who wasted my time on stupid assignments or in teaching me things the US education system expects people to know by 8th grade. I also understood, however, that when I decided not to go to class, I was totally on my own in earning my desired A. I was a consumer, and it was their job not to waste my time. However, if I decided not to RTFM (or at least my textbook), when things blew up, it wasn’t their fault.

Today, that sense of student responsiblity in learning has diminished as consumerism has grown.

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For every force there is an equal and opposite force…

One of the common questions I get is (averaged across many versions) “Why don’t all stars become black holes – don’t they all have gravity? And why don’t they start as Black Holes – didn’t they start with all that mass that made them become black holes?

Balancing stars against gravitational collapse is actually a process that is much more simple than many people think. When a star forms, the pressure and density in the center causes nuclear reactions to occur. These reactions release energy, partially in the form of photons, and the photons exert a pressure on the outer layers of the star. The light pressure pushes outward with the same force that the gravity presses inward. As long as nuclear reactions are occurring in the star’s center, the star doesn’t collapse. When stars die, their nuclear reactions stop and without the pressure from the light they collapse. If a star is similar to the Sun, it becomes a white dwarf, and the force of the electrons repelling one another supports the star. If a star is more massive, the electrons and protons in the stars atoms get crushed together and become neutrons, and the star is supported by the neutrons pushing against each other. If the star is even more massive, there is nothing left to support the star against gravitational collapse and it becomes a black hole.

So, for every force, their is an opposing force, and in black holes, well, inside the BH, we have no idea what is happening, but whatever it is, it kicks in after the material has collapsed small enough that we can get close enough to the center of mass that bad things can happen. Spaghetification anyone?

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