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Overheard in class this term

One of my students, Mike, took very detailed notes during this term's Ay117 Astrostats course. Here are the highlights from my and my TA's, lectures:


“I don’t have great things to say about Mathematica.”

“Who’s feeling lucky?”

“Are there any questions? Great! Actually, it’s better when there are questions. I should stop saying [great!] and say, ‘Are there any questions? No? Aw, that’s too bad.’”

“Oh god, I do NOT understand Mathematica.”

“Never anything positive out of Mathematica—EVER.”

“Let’s say you wanted to raise your hand at a colloquium. You wouldn’t say—unless you’re Dave Stevenson—‘THAT’S WRONG!’”

“Blackboard myopia—when you’re at the blackboard and it’s harder to do math.”

“Chris, why don’t you come up here? I just ran a random number generator to choose one of you guys randomly!”

“Hopefully everybody’s nodding or getting close to being able to nod.”

“This pen, of course, as always, sucks.”

“It’s both profound and profoundly dumb at the same time.”

“I don’t know what the real name for this is. I call it the ‘stair-step plot.’ I’m pretty sure I didn’t make that up.”

“Look, I want to hear a cacophony of, ‘EXPONENTIAL MINUS ONE HALF…’”

“So how did you guys do with the problem set? I see a lot of guilty smiles.”

“Six months ago, I stopped being able to use Caltech Registered. It’s like they really want me to get out of here.”

“The number of words you think should be on your slides, divide that by 2, 3, or maybe infinity, and that’s the number of words that should be on your slide.”

“I hate whiteboard pens.”

“You’ll never find errors if you can’t see them.”

“I hate texting. I’m so bad at it.”

“If you are worried about the difference between N and N–1 , then you are probably up to no good.”

“I don’t even believe in Mathematica.”

Prof. Johnson:

[Trying to show an online video] “Whoa—don’t look at my inbox.”

“I’ll slap your hand if you get those mixed up. No, I probably won’t. I’ll get sued if I do that.”

“As long as we believe in multiplying probability distributions, we’re all Bayesians!”

“Go ahead and talk about that, or just stare at each other confused.”

[On the approximately equal sign]
“Bacon equal!”

“Since Saturday, I’ve been sick, and I’m still sick, but I’m going to power through this!”

“There are many things that I’ll defer to the National Academy of Sciences guy on. I am a fourth-year professor. At the time, I was a first-year professor. But this is one of those times that I didn’t back down. He was wrong.

“This is why astronomers walk around murmuring under their breath, ‘Root N, root N, root N…’”

“The funny thing is, the more you go into astrophysics, especially if you’re an observer, the more your calculus atrophies. If I were a theorist, things would be different.”

“I didn’t know that. That’s hot.”

“We have a guest today, Renée Hložek, which sounds like ‘logic,’ but looks nothing like it.”

“I went so many years hearing people say, ‘I just did MCMC blah blah blah blah,’ and I thought, wow, those guys must be so smart because that thing has so many syllables and one of the words is the name of a Russian guy. It has to be good and it has to be hard.”

“There are more syllables in Markov Chain Monte Carlo than there are lines of code in the simplest MCMC code.”

“A Markov Chain is like when I have too much burbon. What I do now is dependent on where I was last, but I have no memory of how I got there.” [ed note: h/t to Bri on this one]

“Does anybody not understand how cool that is? Because I want to tell you how cool that is.”

“Every talk that I give, I never apologize for saying things that are supposed to be obvious.”

“Every science talk I do, I aim towards the first-year graduate students in the back row. And the professors love my talks because they get to sit there and sagely nod their heads while the graduate students are getting really excited about my field because they can actually understand what’s going on.”

“You don’t need to know this unless you’re fans of trivia.”

“How about that little happy cosmic coincidence?”

Student: “I’m troubled.”
John: “I’m glad! I’m not glad that you’re troubled; I’m glad that you’re telling me.”

[On making fun of other people]
“It’s not so much that I like putting people down as it is I’m trying to instill a fear in you of doing those things too.”

“It’s every astronomer’s—or every experimentalist’s—mantra: more data, more data, gotta get more data.”

“You see an outlier and you say, ‘Out, liar!’”

“I’m going to use a little pidgin math because I haven’t fully thought this through.”

“I’m notorious because I’m known to throw pop finals.”

“That was a previous measurement that was made of the universe in the Journal of Life, the Universe, and Everything.”


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