This story was originally published Feb. 26, 2009.

If you watch the popular CBS sitcom “The Big Bang Theory” about a group of brilliant but socially inept science postdocs, you’re familiar with the work of UCLA Physics Professor David Saltzberg.

As science consultant for the show, Saltzberg is one of the rare experimental particle physicists whose work gets attention from 12 million people a week. It’s a decidedly different experience compared to his usual pursuits: smashing atoms with the world’s biggest particle accelerators and traveling to Antarctica for astronomy experiments related to subatomic particles such as neutrinos.

But since 2006, when a “friend of a friend of a friend” got him involved with the show, Saltzberg has taken on such tasks as dropping scientific details into scripts and introducing actors to real UCLA physicists. In an interview with UCLA Today’s Alison Hewitt, he talks about his sideline job.

Did the actors meet with UCLA physicists for inspiration?

Yes, they walked around our labs and met graduate students and postdocs. One of the actors said he picked up mannerisms from his visit here. The set decorators also visited my graduate students’ apartments to get an idea of how physicists live. In the end, they used those ideas for a pilot, but people thought it was a little — depressing, I think? So they made a new pilot. The characters now live in a place that doesn’t look anything like where my students live!

But the actors and writers really love these characters. One of the early criticisms of the show was that this was poking fun at physicists, at the nerds. But when you watch it, you can see that it’s a celebration of a culture. And of the small number of complaints I hear, no one has ever complained it’s an inaccurate portrayal. They sometimes complain that it’s an unflattering portrayal, but never inaccurate.

Do you really get fill-in-the blank lines in the script that say, “science to come”?

Yes, just like that, in little brackets. [Saltzberg rushes to his computer to pull up an example of a script he worked on.] OK, here’s one, with one of the characters insulting another:

“So I heard about your latest [science to come] experiment — 20,000 trials and no significant results.”

I gave them some science, using a real experiment. Also, physicists don’t really use the word “trials” that way. Little things like that can sound jarring to a physicist, although no one else cares. It’s amazing — and a tribute to the writers — how much they just want to get it right. So in the final draft, it became, “I heard about your latest anti-proton decay experiment — 20,000 data runs and no significant results.”

Do you get to write any of the jokes?

In 30 episodes, I’ve only ever gotten one joke in. I learned very quickly that if I try to pitch jokes, it’s a bit like when I meet a random person at a party who tries to pitch some physics idea at me. These writers are pros, at the top of their field.

How do you decide what kind of science to put in the script?

I often choose something new, so people can learn about recent discoveries. It functions like a news outlet in some sense. It’s also sort of a knowing wink to other physicists watching the show. I’ve put in references to the CERN super-collider and to recent discoveries relating to dark matter. About 90 percent of the matter of the universe is dark matter, so if we can get people to Google dark matter, we have the potential of millions of people learning about what 90 percent of the universe is.

If I publish a paper and I have 100 people reading it, I’m very happy. This television show has 12 million people watching it. That’s enormous. When you consider that the trend these days is to have a lot less science reporting, this may be the only way we have to reach a large audience about what’s new in science.

Are you the only one deciding what science gets in?

Sometimes the writers are specific. They’ll want something very jargony that the audience has no chance of figuring out, or sometimes they’ll want something that someone with high school physics might understand.

In one episode where they’re pushing this box up the stairs, they start using the inclined plane formula. That’s the ultimate physics reference, right? Pushing a box up an inclined plane takes less force than just lifting it straight up. That’s the first week of any physics class. Now I can always say when I teach physics 6A, “I actually found this useful in real life!” Because the writers needed to know whether it was a sine or a cosine in the script! [Editor’s note — If you’re curious, Saltzberg did some quick calculations during the interview to check the answer. It’s sine.]

You also write all the esoteric equations that appear on the whiteboards on the show. Where do those come from?

I write the equations so it doesn’t look like nonsense. Often, things that the characters say they’re working on will match up with what’s on the whiteboard. It’s just there as background, so it probably doesn’t matter. But I have fun with it. I found out there are people trying to guess what’s on there and why.

Once I had some graduate students come to a taping, and they had just taken an exam, so I put the solutions on the whiteboard. It took them a few minutes to realize what they were looking at, but they were thrilled to see it in the show. When the great physicist John Wheeler died last year — he coined the term “black hole” — I put his most famous works up on the board as a tribute. So there are those little nods.

Do a lot of your colleagues and students join you at the tapings?

I know a few professors who watch the show — more than I would have expected — and they like it. And I also get positive feedback from graduate students. Since it’s taped in front of a live audience, and I go to every taping, I do get a lot of requests, and I always can get them seats. I’m also allowed to bring one special person with me down to where the writers stand watching the show from the side. It’s almost always a physicist. The writers call them the “geek of the week.”

Are viewers picky about the science being accurate?

In the beginning, I don’t think anyone expected the show to get the physics right. But there were a number of bloggers who commented on an early episode. One character does a little trick at dinner, spinning an olive in an upside-down glass, and the character’s date says, “It’s centrifugal force,” and of course the bloggers are saying in their heads, “Well, it’s not centrifugal force, it’s centripetal force that’s keeping it in.”

The next thing they know, the other character launches into a description saying “It’s actually centripetal force, and here’s why,” and it’s a completely correct description. One friend, a physics professor at my old university, said he saw that and fell off his chair.

Do you think the science inspires any interest from students?

Definitely. Just as an example, I got an e-mail from a high school student named Olivia from outside Chicago. There was one episode where Leonard kisses Leslie, and his friends ask him how it went. He says, “Well, the Earth didn’t move. Except for the 383 miles it was going to anyway.” Well, Olivia tried to calculate the 383 miles based on a five-second kiss and how fast the Earth was turning. Didn’t work out. Then she said, “Oh, maybe it’s because the Earth is traveling around the sun.” Still didn’t work out.

So she e-mailed me. I said, “Well, you haven’t included the fact that the solar system is going around the center of the galaxy every 250 million years,” so she Googled it, figured it out and came back with the right number. If there’s one student e-mailing me about it, how many other hundreds are looking it up on their own?

Is that the kind of situation where the writers ask you to fill in the blank with the number of miles the Earth travels in five seconds?

Well, in this case the writers had a number, but first of all, it’s a meaningless number, because speed is always relative to something else. In the universe there is no obvious signpost overall. So there is no right answer, but theirs was less right.

But these writers are really brilliant. I really enjoy consulting. When I get the scripts to review and I read them, I find myself laughing out loud. It’s embarrassing.

Can’t get enough of “The Big Bang Theory”? Saltzberg is also blogging about the science behind each episode of the show at Now, viewers without a science background can get a behind-the-scenes glimpse of the show and get an education from a top UCLA physicist.