Gravity 7: Recipe for Destruction (Making Black Holes)

by Shane L. Larson

Black holes emit no light, by definition. For many years, the only hope astronomers had of detecting these enigmatic objects was to look for how they interact with other astrophysical objects, like stars and gas. Astronomers have been around the block a few times — they’ve studied a lot of stars, and seen a lot of gas in the Cosmos. What should they be looking for that would clue them in when the stuff they can see has drifted near a black hole? What do black holes do to things that fall under the influence of their gravity?

If you’ve ever heard about or read about black holes, you’ve learned that their gravity can be strong — extremely strong. This leads to a somewhat deceptive notion that black holes are like little Hoovers, running all over the Universe sucking things up.  The reality is that a black hole’s gravity is strong and can have a profound effect on the Cosmos around it, but only up close.

To get a handle on this, it is useful to go back to the way we first started thinking about gravity — in terms of a field. In the field picture, the strength of gravity — what you feel — is given by the density of field lines in your vicinity; gravity is stronger when you are surrounded by more field lines. There are two ways to increase the strength of the gravitational field.

The easiest way to make gravity stronger is to have more mass. Mass is the source of gravity; when we were drawing gravitational fields, the number of field lines we drew depended on the mass of the object.  The Sun is much more massive than the Earth, so we draw many more field lines to represent its gravitational field.

Two observers (Stick Picard, top; Stick Spock, bottom) are the same distance from objects. For the person near the smaller object, they feel weaker gravity (evidenced by fewer field lines around them).

Another way to increase the strength of gravity is to make an object more compact. You can see this by considering two stars of equal mass, but one smaller than the other. How do their gravitational fields compare? Far from either star, the gravitational fields look identical. There is no way to distinguish between the two based on simple experiments, like measuring orbits. But suppose you were down near the surface of each star. Here we notice something interesting. Both stars have the same number of field lines, because they have the same mass. But down near the surface of the smaller, more compact star the lines are much closer together. This was the signature of gravity being stronger.

Imagine two stars with exactly the same mass, but one is larger in size (top) than the other (bottom). Observers far from either star (Stick Spock, both panels) feel the same gravity if they are the same distance away. For close-in observers (Stick Geordi, both panels) the gravity is stronger. But for the compact star (bottom) the observer can get closer, and when they do, they feel even stronger gravitational forces. The gravity is much stronger near a compact object.

The field picture of gravity is associated with the idea of forces (it is a “force field”), which is the foundation of Newton’s approach to gravity. But one of the requirements of general relativity when it was developed was that it correctly describe situations where we would normally use Newtonian gravity, as well as any situation that required relativistic thinking. We’ve seen in these examples that gravity gets stronger if an object is more massive, or if it is more compact. In the language of general relativity, we would say “there is stronger curvature” in both these cases. Remember our mantra: “mass tells spacetime how to curve.” Spacetime is told to curve more where the masses are bigger, or when the mass is very compact.

So what does this tell us about black holes? It says that to make an object whose gravity is so strong that the escape speed is the speed of light, I can do one of two things: I can dramatically increase the mass, or I can make the object more compact.  This is the first clue we have to where black holes might come from — they have to be either very massive, or extremely small. We actually encounter both in the Cosmos, as we shall see, but for the moment let’s focus on the small ones. So how do you make things extremely small?

Wrap a balloon in aluminum foil. The foil is like the stuff of the star; the balloon is an outward force, keeping the star from collapsing.

Let’s do an experiment to think about this. Go find a balloon and some aluminum foil. Blow the balloon up (it doesn’t have to be huge) and wrap it in aluminum foil.  This is a mental model of a star at any given moment in its life. Gravity is always trying to pull everything toward the center. But the star is not collapsing — why not?  Deep in the cores of stars, the temperature and pressure is so high that nuclear fusion occurs — through a series of interactions with all the nuclei that are packed together, hydrogen is “burned” into helium. This process releases energy — it’s nuclear fusion power! In your balloon and foil model, the foil is stuff in the star — all the churning roiling gas and plasma that make up the body of a star. What is keeping it from collapsing? In this case it is the balloon, pushing the foil outward — the balloon is acting like the fusion energy bursting out from the core, supporting the star and keeping gravity from collapsing it.

Gravity (turquoise arrows) is constantly trying to pull the star inward on itself. The pressure from the nuclear fusion generating energy in the core presses outward (yellow arrows) preventing the star from collapsing.

As a star ages, the fusion process in its core evolves, slowly burning the core fuels into heavier and heavier elements, until a large core of iron builds up. There are no effective nuclear reactions that can sustain the burning of iron into heavier elements.  The iron is effectively ash (that’s what astronomers call it!) and it settles down into the core.  The iron is not burning, so there is no fusion energy pushing outward against gravity’s desire to collapse the core — what’s stopping it?

In addition to the iron nuclei, the core is also full of the other constituents that make up atoms, electrons.  Electrons are a particular kind of particle we encounter in the Cosmos called a fermion. Fermion’s are okay to hang out together, provided they all think they are different from one another (in the language of the physicists — the fermions all have to have different “quantum numbers”); this is a well known physical effect known as the Pauli Exclusion Principle. If you do pack fermions together they dislike it immensely. They start to think they are all looking the same, and they press back; this is called “degeneracy pressure”, and it is what keeps gravity from being able to crush the iron core of the star.

When gravity overcomes the electron degeneracy pressure in the iron core (pop the balloon), there is nothing pushing outward against gravity, so the core can collapse.

High above, the star continues to burn, raining more and more iron ash down on the core. The mass of the core grows, and the gravity grows with it. When enough iron amasses in the core, the gravity will grow so strong not even the degeneracy pressure of the electrons can oppose it. When that happens, gravity suddenly finds that there is nothing preventing it from pulling everything down, and the iron core collapses.  In your model, this is equivalent to popping your balloon — you’re left with a lot of material that is not being supported at all, so it collapses.  Collapse the foil shell in your hands — you are playing the role of gravity, crushing the material of the star down into a smaller and smaller space.

When the collapse occurs, the iron nuclei are the victims. The compression of the iron core squeezes down on the iron nuclei, disintegrating them into their constituent protons and neutrons. The extreme pressure forces protons and electrons to combine to become more neutrons (a process creatively called “neutronization”). In less than a quarter of a second, the collapse squeezes the core down to the size of a small city and converts more than a solar mass worth of atoms into neutrons. We call this skeleton a neutron star.

Gravity wants to compress all the matter, to pull down as close together as it can get. The explosion helps gravity move toward its goal by applying astronomical pressures from the outside, squeezing and squeezing the matter down. What stops it?

You hands act like gravity to crush the foil into a small remnant of its former self. There is a minimum crushing size, because the foil presses back against your efforts.

Let’s go back to your model. The balloon has been popped — that’s gravity overcoming the supporting pressure of the electrons. The foil has collapsed — that is gravity pulling as hard as it can to get all the material down into the center. Now squeeze that lump of foil as hard as you can; make the smallest, most compact ball of foil you can. Odds are there is some minimum size you can make that ball of foil. What is keeping you from squeezing the foil smaller? The foil itself is getting in the way! It is pushing back against the force that is trying to crush it — you — and you are not strong enough to overcome it!

This is the case with the neutron star. When neutrons are so closely packed together, their interactions are dominated by the strong nuclear force, which is enormously repulsive at very short distances. As more and more neutrons are packed into a smaller and smaller space, they become intensely aware of one another and the pressure from the strong nuclear force grows until it is strong enough to oppose gravity once again.  The collapse stops, suddenly.

The iron core is heavy (more than a solar mass) and moving fast (between 10-20% the speed of light) — it is not easy to stop so suddenly. When the center of the core stops, the outer layers of the core are unaware of what lies ahead. In the astrophysical equivalent of a chain-reaction traffic pile-up, the layers crash down on one another; the outer layers rebound outward.  This rebounding crashes into the innermost layers of the star above the core, setting up a shock wave that propagates outward through the star.  The wave begins to tear the star apart from the inside.

The Western Veil Nebula (NGC 6960), just off the wing of the constellation Cygnus. Visible in amateur telescopes, it is one of the most exquisite supernova remnants in the sky. [Wikimedia Commons]

Energized by an enormous flux of neutrinos produced by the newly birthed neutron star, the shock is driven upward through the star, until it emerges through the surface, destroying the star in a titanic explosion known as a supernova.  It is an explosion that would make Jerry Bruckheimer proud — the energy released is enormous, for a time making the exploding star brighter than all the other stars in the galaxy combined. The material of the star is blown outward to become a supernova remnant, a vast web of ejected gas and atoms thrown out into the Universe. We see many, many supernova remnants in the galaxy — every one of them is unique, they are all exquisite and beautiful in ways that only the Cosmos can create.

Left behind, slowly settling down into a well-behaved stellar skeleton, is the neutron star.  At the surface of the neutron star, the gravity is enormous — about 200 billion time stronger than the gravity at the surface of the Earth. The escape speed is 64 percent the speed of light. If you fell just 1 millimeter, you would be travelling at 61,000 meters per second (136,400 miles per hour!) when you hit the surface!

Lego Neil deGrasse Tyson and Lego Me visit the surface of a neutron star. [click to enlarge]

But this is still not the extreme gravity of a black hole. If a star is massive enough, the crushing force of the collapsing star and the ensuing explosion is so strong it cannot be stopped even by the protestations of the neutrons. In fact, the infalling matter crushes the matter so strongly that gravity becomes triumphant — it crushes and crushes without bound. The strength of gravity — the warp of space and time — soars. At some point the escape speed at the surface of the crushing matter reaches the speed of light — the point of no return has been reached, but the matter keeps falling right past the event horizon, continuing to fall inward under the inexorable pull of gravity. All the matter is crushed into the smallest volume you can imagine, into the singularity, at the center of the empty space we call the black hole. No force known to physics today is strong enough to overcome this event.

Different effects in astrophysical systems fight against gravity’s inexorable pull. If the gravity gets strong enough, nothing can prevent the collapse to a black hole.

The process just described is known as core-collapse and is just one way that astronomers think black holes might be made. Similar explosive events that lead to collapse include the collision of two neutron stars, the parasitic destruction of a small star by a compact companion that grows its mass large enough to collapse, and possibly even the collision of smaller black holes to make larger black holes.

So how compressed do you have to be to become a black hole? The answer for a perfect ball of matter is called “the Schwarzschild radius.” If you squeeze an object down to a ball that fits inside the Schwarzschild radius (that is, it fits inside the event horizon) then no known force can stop gravity from collapsing that object into a black hole. For the Sun, the Schwarzschild radius is about 3 kilometers — if you shrink the Sun down into a ball just 6 kilometers in diameter, the size of a small city, it will be a black hole. For the Earth, the Schwarzschild radius is about 1 centimeter — if you shrink the Earth down to the size of a marble, it will be a black hole.

What it would take to make the Sun or the Earth into a black hole. The Sun as a black hole would cover your town, but you could carry the Earth in your pocket (though this is NOT recommended).

Given a notion of how black holes form, astronomers can start probing the Universe, peering into places that should give birth to black holes. The same physical effects that we used to understand their formation can be used to understand how they interact with the Cosmos around them, giving astronomers clues about how to detect them. Next time, we’ll use this information to find out how black holes influence the Universe around them, and use that information to go black hole hunting in the Cosmos.

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This post is part of an ongoing series written for the General Relativity Centennial, celebrating 100 years of gravity (1915-2015).  You can find the first post in the series, with links to the successive posts in this series here: http://wp.me/p19G0g-ru.

[9 March 2015] This is revised version of the original post. I owe many thanks to a colleague who pointed out that my original explanation of core-collapse followed very old ideas about how stars die. In this revision, I have endeavoured to present a correct but still clear picture of what is going on. Any inaccuracies that still persist are my own.

Cosmos 0: It’s Time to Get Going Again

by Shane L. Larson

At midnight on a December night in 2001, I waited breathlessly in a darkened theatre in Los Angeles, surrounded by my friends from Caltech, for the world premiere of Peter Jackson’s monumental film based on J.R.R. Tolkien’s masterpiece, The Fellowship of the Ring.  In the 47 years following the publication of the first volume of The Lord of the Rings, Tolkien’s work had ascended to become a cultural icon, and had launched the worldwide obsession with fantasy, swords and sorcery.  It was, by all accounts, the gold standard against which all other fantasy novels were measured. To dabble with trying to translate Middle-Earth to the screen was foolish at best, and had failed before.  There was, and still is, much arguing and hand-wringing about the translation, but by-and-large it was successful. If nothing else, it introduced a whole new generation of people to Hobbits, Ents, and the Rohirrim.

In the months leading up to the premiere, I resolved to read The Hobbit and The Lord of the Rings again, before I saw the films. Why?  Because it would be the last time that the visions of Middle-Earth that I carry around in my head would be mine and mine alone. After seeing the Jackson films, Middle-Earth would forever be an admixture of Tolkien’s writing, my imagination, and Jackson’s visuals.

Fast forward 12 years, and we find ourselves on the cusp of a supposedly foolhardy reimagining once again.  In March, Fox and the National Geographic Channel will broadcast a new public science series, Cosmos: A Spacetime Odyssey.  It is a follow-on to the classic 1980 television series by Carl Sagan, Cosmos: A Personal Voyage.  Carl Sagan left this Cosmos long ago, returned to the stardust from whence we all came in 1996. The new imagining of Cosmos will feature prominent science communicator, Neil deGrasse Tyson, and is being produced by Ann Druyan (who produced the original Cosmos), and animator Seth MacFarlane.

Recently, when the first trailer for Cosmos: A Spacetime Odyssey aired (watch the trailer here on YouTube), one would have thought the apocalypse had come.  The internets instantly polarized (an all too common behaviour in modern society).  There were those who decried the new show as too flashy, too entertaining to be a useful vehicle for science.  There were those who saw little nods to the original series that promised this would be just as rich in deep thoughts and provocative musings as the first Personal Voyage. There were Sagan fans who insist Tyson couldn’t measure up to Carl’s charm. There were Tyson fans who are sure this will be awesome because how could it not be with Neil guiding us?  Then of course there are those who think this is all just hero worship; why should we care about Carl Sagan, or Neil deGrasse Tyson? 

(L) Carl Sagan. (R) Neil deGrasse Tyson.

In addition to the usual internet-mongering about who is the better science host, there is also a low rumble that the time of hour-long episodic television science has come and gone. The suggestion is that the way to communicate science in the future is in microblogs like tumblr and in short YouTube clips more suited to the short attention span of modern youth and modern politicians. Perhaps, but there is plenty of hour-long television that is still eminently successful and ongoing today, it’s just that very little of it is science (Mythbusters non-withstanding). The underlying truth of what matters today is not the format, it is accessibility — people don’t have to sit in front of a 50 kg CRT television set to see the new Cosmos (nor the old one!).  Instead, they can stream it to their smartphones and tablets, watching Cosmos as their train speeds them home from work, or while they’re squirreled away in the corner of a Jamba Juice in Cleveland, or while they are waiting for the lasagne to cook for Thursday night’s dinner.

Cosmos: A Personal Voyage is subject to as much fandom as any superhero might be. There are factions who fanatically defend its wisdom, foresight, and timelessness.  There are other factions who think its visuals and science content are hopelessly dated, exhibiting that Cosmos has outlived its usefulness, and was indeed a “product of its time.”  What is true, no matter how you slice it, is that there is a entire generation of people who identify Cosmos as one of the most important influences in their introduction to science, whether they are armchair-citizen-scientists-advocates, or professional scientists themselves.

I certainly count myself among a large group of scientists who ascribe some of the inspiration for going into science as being exposed to Carl Sagan at an early age (as I have written about before here and here).  In my case, Sagan’s gift for communicating science effectively swirled around in my brain and gelled into one of the central themes of Cosmos, namely that the Universe was understandable. Maybe Sagan just made it seem understandable, but the fact that I walked away thinking I knew something, thinking that I could do experiments to know more, and believing that I could understand the outcomes of any experiments inspired me to walk the path I walk. In the days after each episode, I would have long conversations about the deep ideas that watching Cosmos had inspired in me.  I not only learned about the principles of science, but also the history of science and how we came to understand the world, parts of the story I never knew before. I’d talk with my parents about Einstein and relativity, I’d talk with my teachers about walking across the Earth to discover its size, I’d talk with my friends about soaring over the canyons of Mars in a spacecraft of our own design.  I had important and inspiring conversations that I still remember today.

Later in life, I came to understand that not everyone can explain things as clearly nor as eloquently as Sagan (many science teachers remind me of Mr.Turkentine in the 1971 movie, Willy Wonka and the Chocolate Factory; check out Turkentine’s lecture on percentages, and tell me if it seems familiar!).  This inspired me to think harder about how I communicate science, and to practice (hence, this blog you are reading).  It is a never-ending process of learning, refining, and trying again.

Howard Thurman (photo by LIFE Magazine).

The world needs scientists who communicate for many reasons. First and foremost among them is there are serious problems in modern society that science can help resolve; indeed, there are serious problems that very likely only science can solve! People need to understand how scientists work, how science works, and how our knowledge of Nature changes and evolves; if people don’t understand these things, they won’t trust science when they need to.  But the second and altogether more important reason the world needs scientists to communicate is that scientists harbor a boundless, unbridled passion for the knowledge of the world. There are few people I have encountered in my life who have discovered joy and passion and come alive as scientists do.  In the words of the great philosopher Howard Thurman, “What the world needs is people who have come alive.” Scientists have that in spades.

When I think about how I discovered science, Cosmos holds a prominent role in my memory.  I came alive because of Cosmos.  So I am waiting with unbearable anticipation for Cosmos: A Spacetime Odyssey.  I know far more science than I did when I first saw Cosmos long ago, but I still revel in and enjoy cogent, lucid, and entertaining explanations about how science is all around us in our everyday lives. I’m looking forward to being able to use the new Cosmos as a vehicle to talk to people about science.  I’m looking forward to the conversation starting again!

Just like those heady days before the premiere of The Fellowship of the Ring, I feel the need to revisit Carl Sagan and Cosmos: A Personal Voyage once again. Before we take a walk through billions of years of Cosmic evolution and discovery on a new journey, I want to hear Sagan’s sonorous voice in my head once again, to feel the wonder for the Cosmos once again as I felt it so long ago. So between now and March, I’ll take the time each week to sail alongside Carl Sagan in a ship of the Imagination, drawn by the music of Cosmic harmonies, visiting worlds of dreams and worlds of facts. Starting in December, once a week, I’ll post some reflections inspired by these Cosmic musings, my last thoughts before we once again stretch the boundaries of our contemplations with new voyages of discovery.

I hope I’ll see you on the trip.

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For reference, here are links to the successive posts in this series:

Cosmos 1: The Shores of the Cosmic Ocean (3 Dec 2013)

Cosmos 2: One Voice in the Cosmic Fugue (10 Dec 2013)

Cosmos 3: Harmony of the Worlds (19 Dec 2013)

Cosmos 4: Heaven and Hell (27 Dec 2013)

Cosmos 5: Blues for a Red Planet (1 Jan 2014)

Cosmos 6: Travellers’ Tales (8 Jan 2014)

Cosmos 7: The Backbone of Night (15 Jan 2014)

Cosmos 8: Journeys in Space and Time (23 Jan 2014)

Cosmos 9: The Lives of the Stars (29 Jan 2014)

Cosmos 10: The Edge of Forever (5 Feb 2014)

Cosmos 11: The Persistence of Memory (14 Feb 2014)

Cosmos 12: Encyclopaedia Galactica (25 Feb 2014)

Cosmos 13: Who Speaks for Earth? (3 Mar 2014)

Cosmos 14: A Personal Voyage (9 Mar 2014)

A Rant Among Friends

by Shane L. Larson

<rant>

When you grow up and get a job, there is inevitably a Saturday night when you are talking on the phone with your mom, or enjoying a glass of Chianti with your date, and you have to answer The Question: “So what exactly is your job?” Then you fumble around for a few minutes trying to explain actuarial tables, or managing the supply line for a 7-11, or what a Toyota service manager actually does. Most careers are not reducible to a simple, one sentence sound bite understandable to relatives or members of the opposite sex. Almost certainly every job has different parts and pieces, each of which are worthy of their own sound bite!  If you love your job, then you want it sound exciting and sexy; you want your sound bite to be a sales pitch that might convince someone else to join your profession.

What’s in the Fear Closet?

As scientists, in particular scientists who are also university professors, my colleagues and I spend a lot of brain power thinking about this last part — how do you make sure people adopt science as a profession? I’m not yet besectacled and grey; my hair hasn’t yet gone the way of Big Al Einstein’s, so maybe I don’t yet have the wisdom (cynicism?) of my more elderly colleagues.  But late at night, when the world is slumbering and my grading is done, I like to open the Fear Closet in the back of my mind. Very seldom are Mike and Sully there to greet me; instead I usually find a big elephant that we scientists like to ignore: we often suck at making our profession appealing to anyone. Furthermore, we have an idealized model of who makes a good scientist that, like an unrealisticly proportioned Barbie doll, is not a good approximation of any person (or scientist) I know. The fears in the Closet all add up to one inescapable possibility: that like the dinosaurs of yore, who never became intelligent enough to save their race from impending doom, scientists could become extinct.

I’m a bit worried about the radio astronomers...

Now I don’t think that is a realistic fear; there are always going to be scientists.  But the landscape of our modern civilization is such that if scientists don’t evolve, we will become relegated to the backwaters of our society, currently occupied by mimes, disco, and Elvis impersonators.

This door of the Fear Closet has been open a lot lately, because scientists have an annoying habit of thinking they know everything, which means we (the scientists) think we know how to make other people love and revere science. I’ve been staring into the Closet with this in mind, and thinking back to my high school consumer affairs class where I was taught the Very Important Lesson: customers have all the power, because they have the choice to spend their money on your product or not.  If the consumers hate your product, they won’t buy it, and your business will fold. If the way you do business becomes obsolete, you won’t have any customers, and again your business will fold. Do you still have a Blockbuster down the street from your house? How about any product from Kodak? Maybe you still watch the XFL?  No? These ventures all failed to respond to the external demands placed on them by their consumer base; they failed to evolve.

Some notable examples of failing to evolve in response to customer needs and desires. Recognize any of these?

This must be true in science too — if people don’t like the way we present and promote and sell science, they will ignore us.  An interesting case study on this point is a very pointed article a colleague of mine linked to the other day, written by Maura Charette (an eighth grader!), reflecting on STEM (Science, Technology, Engineering and Mathematics) careers (link to article).

Ms. Charette’s essay is brilliant, and as STEM professionals we should take many of her points to heart. I don’t disagree with anything she says.  But in the interest of inciting discussion, why don’t I summarize what I took away from the article (for future reference, when examining the contents of the Fear Closet):

(0) Ms. Charette writes, “while we hear science and math careers are fun, interesting, and well-paying, the actual scientists and engineers who visit our schools seem very one-dimensional.”  Despite the ascendance of geekdom into the mainstream of popular culture, scientists still maintain a stranglehold on being the opposite of cool; we are the George MacFly’s of the geeks. Not to say that there aren’t superstars among us — the public adores Neil deGrasse Tyson and Bill Nye. People like Brian Greene and Lisa Randall are at least commonly known names in some circles.  But the vast majority of us exude the exact opposite of what we want to inspire — excitement and fun.  We are, as Ms. Charette so aptly observes, one dimensional. Now it is not possible, nor desireable, for all of us to become great public personalities. But what we must stop doing is discouraging, disdaining, and ostracizing our colleagues who are good at this. Elitism abounds in science; we place far more value (as a group) on the trappings of science — research, discovery, appearing smart — than we do on the interfaces with science — teaching, writing, communicating. Many of those who act in the interface roles are not afforded the same encouragement or respect as those who act in the “popular” roles (this is in fact, a common occurrence in all academic fields, particularly at universities).  Communicating our science to the society that funds (and tolerates) us is as noble a cause as any bench science you care to name, and as it turns out, just as important.

(1) Let’s be blunt — we don’t make science exciting. If I may be a bit bold and exhibit one of the annoying traits of adults, let me rephrase Ms. Charette’s message in my own words (a classic classroom exercise!): scientists suck. Particularly at teaching.  Not all of us; many of us are great teachers (my colleagues at Weber State University Physics come to mind).  But all too often what we teach lacks the fire, the passion, the core of what drew every one of us into the field.

How we teach adversely affects opinions about our craft. We need to consider perspectives that draw people into what we want them to know…

Why did YOU get into science?  I got into science because black holes are freakin’ AWESOME (and pretty much every 9 year old on the planet agrees with me). When I lay awake at night, staring at the patterns of light on my bedroom ceiling and thinking about black holes, I don’t push tensors around in my head and think about geodesic deviation and metric functions. I think about black holes tearing stars apart; I think of black holes lying in wait at the bottom of the galactic core, waiting to suck up unsuspecting stars and gas clouds.  These are the things to talk to people about and to teach about.  The technical matters are important — no doubt about it — but what people need is that deep seated sense of wonder about the world around them that makes them lay awake at night pondering how high grasshoppers jump compared to their body length, and why the Great Lakes don’t have huge tides like the ocean, and how long it will take the Rocky Mountains to wear down into sad little nubbins like the Appalachians.  You and I stay in science for those reasons, for the wonder of it. We’ve learned the technical tools, and we use them to illuminate the world and make our understanding more remarkable and enjoyable.  But we didn’t come to science because of the technical stuff.  Teach to the passions that draw people.

(2) Scientists place an over-emphasis on good grades. One of the most disturbing things (to me) that Ms. Charette wrote is this: “to pursue and succeed in those one-dimensional jobs, you have to study very hard and get good grades in the most difficult subjects.”  As near as I can tell, someone in eighth grade is already considering giving up on science because of grades.  Getting good grades is the conventional folklore, which scientists loudly advocate, and it makes me want to puke at night worrying about how many kids we drive away from science because of it.  Does having good grades help be a good STEM professional? Of course it does, but it is no substitute for hard work and a good work ethic.  Some of the people I know with the most flawless report cards in math and science SUCK at being a STEM professional!  Why? Because they are good at doing homework, finding out the “right” answer using well known conventional thinking.  But they completely lack any creativity, imagination, intuition, or ability to make brilliant leaps of logic that are so crucial to making important advances in science.

(2.5) Just to prove you don’t need good grades to be a successful scientist, let me bare my soul to the flames of the Internet. I got a C in thermal physics as an undergraduate.  I took Calculus II twice (on purpose) because I didn’t understand it the first time; the second time I decided I wasn’t meant to understand integration by parts and moved on (and I still can’t recognize when to do it). I got a LOT of B’s (and at least one C), and only a handful of A’s in graduate physics.  After my first year of graduate school, the department head in Physics called me into his office and told me I didn’t have a future in science, and I should drop out and go do something else with my life.  To encourage me to see the world his way, he didn’t provide any summer support for me (but did for the rest of my classmates). I ignored him, of course. That summer I went out and found another job and met two of the great scientific mentors in my life (Dr. Kimberly Obbink, and Dr. Gerry Wheeler). I finished my courses, and I completed my Ph.D. without difficulty. In the years since, I like to think that I’ve been a reasonably successful scientist by most of the measures of my professional community.  I had postdocs at some of the best institutions in the world (JPL, Caltech, and Penn State); I’m a tenured professor; I have 50 some-odd publications; I’ve successfully acquired multiple federal grants to support my students and my research; I was “Professor of the Year” one year.  CLEARLY he was right; you have to have perfect grades to be a good scientist. WTF was I thinking?!

My fort!

(3) Lastly, let’s review the title of Ms. Charette’s essay: “Is a Career in STEM Really for Me?” Really?  Have we stooped to the point where 8th graders have to be cognizant and concerned with their careers?  In 8th grade I was 13; I didn’t enter graduate school until I was 21 and I didn’t get my PhD until I was 29.  When I was 13, I wanted to be an astronaut, not a relativistic gravitational astrophysicist. When I was that age, I didn’t worry about careers yet; I was BUILDING FORTS!  If you look at my fort, it is clear that there was some STEM in there — obviously some math, as well as some attempts at engineering. 🙂  I was doing “STEMy” kinds of things (as were both my brothers — one is now a diesel mechanic, the other a crop scientist — both STEM professionals).  We know that middle school years are the years where kids lose interest in science, but making them think about STEM careers is NOT the way to keep them engaged!  Neither are marshmallows and straws.  Kids are smart, intelligent, and capable. They live in a world filled with modern marvels that are commonplace to them: smartphones, streaming digital media, microwave popcorn. We need to field science that is engaging enough to compete in that marketplace and we need to do it sooner rather than later (just ask Blockbuster and Kodak how easy it was to catch up…).

Me and Xeno.

So what to do about all of this?  My mother taught me that one cannot simply complain about the world without offering solutions. Be a problem solver, not a trouble maker. Yes, Ma; I remember.  I’m just not sure what to do about it yet; I promise to work on this.

My therapist (Xeno) says ranting is not good for my blood pressure, so I’ll stop now.  But if you have any great ideas, by all means let me buy you a beer and a pizza so we can figure out what to do next!

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