Dr. Saltzberg, David...

...is a physicist.

He is smarter than I am.

But truthfully, I don't know what he does.

- How was your day? - Mm.

You know, I'm a physicist, so I thought about stuff.

He's not only doing business for the world, he's doing business for our show.

He double checks all the science and--

You know, is also helpful in some of the jargon for us.

The right paradigm-shifting reinterpretation of the universe.

Loop quantum gravity better unites quantum mechanics...

...with general relativity than does string theory.

Free electron laser from my x-ray diffraction experiment.

The footnote where I illustrate mirror symmetry...

...by likening it to the Flash playing tennis with himself.

The locus of my identity is totally exterior to me.

I'm a particle physicist by training.

But lately I've been lured a little more into astrophysics and astronomy.

And so those of us who find ourselves in this situation...

...are called particle astrophysicists.

I got a phone call from a friend of mine, who's a--

An astrophysicist now at University of Hawaii.

He was asked a few questions by these people...

...who were doing a sitcom about physicists.

And they needed to find a physicist.

PRADY: Will you work by e-mail with us?

Once it was going to series, we realized we need somebody to help.

So we asked him for recommendation and we got to Professor Saltzberg...

...and we contacted him and said:

"Do you have, maybe, a grad student...

...or someone who could come in and help us?"

And he said, "Oh, could I do it?"

[CHUCKLES] And, "Okay."

LORRE: We knew we are out of our depth.

If we're gonna write about geniuses, we better damn well have one around.

My favorite moment is always when we get to the physics part of the script.

And we sit there and stare at the screen and I'm trying to figure out--

And Bill would always say, "We could sit here forever, Chuck.

We're not gonna become physicists and write this."

So we had no idea what we were doing.

This is the important scientific question that has to be--

Could we ask David to explain this?

Well, that's interesting because if it's-- If that ties in--

That is renormalization going on.

SALTZBERG: One thing I always look forward to do with the show...

...is I get the scripts from Chuck and Bill and the other writers...

...and often there's brackets and it says, "science to come"...

...about some new project that Leonard's working on, for example.

I think you'll find my work pretty interesting.

I'm attempting to replicate the dark matter signal...

...found in sodium iodide crystals by the Italians.

So no original research?

No.

Well, what's the point of my seeing it?

I could just read the paper the Italians wrote.

In those small places, I kind of have some free reign.

And I pitch a few ideas to them and see which ones they like.

And often it's something that you can Google about or check on Wikipedia...

...and see that these are often current topics.

My flash drive has my paper on astrophysical probes...

...of M-Theory effects in the early universe...

...that I was going to give to George Smoot at the conference.

Why do you have to give your paper to George Smoot?

It's brilliant. He needs to read it.

The most fantastic thing about him...

...other than the fact that he's doing fact checking...

...is the fact that if there's a problem it's on him.

PRADY: He also spends time on the set.

The white boards that are on the set in Leonard and Sheldon's apartment...

...and he makes sure they're right.

SALTZBERG: It's fun when we tie it to the episode.

Professor George Smoot was here.

And he was involved in some of the measurements...

...of the cosmic microwave background radiation.

And won the Nobel Prize.

And so I had a diagram of the apparatus the team used on the COBE satellite...

...and we put that on the board and he saw it and I think he liked it.

This is actually related to one of the jokes in last week's episode.

This physicist goes into an ice cream parlor every week...

...and orders an ice cream sundae for himself...

...and offers one to the empty stool sitting next to him.

The owner finally asks him what he's doing. The man says:

"Quantum mechanics teaches us...

...that it is possible for the matter above this stool...

...to spontaneously turn into a beautiful woman...

...who might accept my offer and fall in love with me."

The owner says, "Lots of single beautiful women come in here every day.

Why don't you buy an ice cream for one of them...

...and they might fall in love with you.“

And the physicist says, "Yeah, but what are the odds of that happening?"

It's a little insulting, don't you think?

And so we have here is a-- The basic diagram of quantum tunneling.

Which would be basically what's the physics behind that joke.

We trust David Saltzberg a lot. He may be, you know, completely conning us...

...and this is all nonsense, so we wouldn't know.

I liked your paper on grand unification using string network condensates...

...and wonder how you determined that three dimensional string nets...

...provided a unified picture of fermions and gauge bosons.

I also once had a chance to play a very inside joke.

I had an Honors Physics class...

...and they came to the audience to watch the show. They were fans.

And on the white boards, I had the answers to the exam they just took.

How would I know? I'm not even sure I get it.

PRADY: They are a group of people...

...who are working to understand the fabric of the universe.

The people who sort of look into the eye of God every day as a job.

And what an amazing group of people they are.

And we made the decision to make them physicists.

Whatever small contribution I have is maybe...

...what particular experiment they're doing that week or that season, or--

You know, what particular little objects Raj might be looking at.

So in the details, I get a chance to contribute.

I gotta ask. Why didn't you just get a license at 16, like everybody else?

I was otherwise engaged.

Doing what?

Examining perturbative amplitudes in n=4 super symmetric theories...

...leading to a re-examination of the ultraviolet properties...

...of multi-loop n=8 supergravity using modern twistor theory.

So Sheldon is a theoretical physicist.

And people like him, probably best described...

...as intellectual descendants of people like Einstein or Niels Bohr.

Oh, there's my missing neutrino.

You were hiding from me as an unbalanced charge...

...weren't you, you little subatomic dickens?

They're trying to make a mathematical description of everything in the universe.

A small order.

It takes a certain amount of arrogance to think one can do it...

...but there's been quite a lot of success in that field too.

We're examining the radiation levels of photomultiplier tubes...

...for our new dark matter detector.

Sweetie, sweetie, Dave was talking.

Most recently, the problem that Leonard's been working on...

...is a problem called, what is the dark matter in the universe?

A lot of indirect measurements show us that 90 percent of the universe--

Ninety percent of mass in the universe...

...is made of something that we don't know what it is.

And so there are lots of experiments going on right now...

...people trying to detect what is this matter moving around in the galaxy?

What is it made of?

So, what's your news?

Remember that object I spotted beyond the Kuiper Belt?

Oh, yeah. 2008-NQ Sub 17.

Or as I call it, Planet Bollywood.

So Raj is an astronomer or astrophysicist.

Anything?

Actually, I was just checking my e-mail.

And his research has him studying objects orbiting the sun...

...but in orbits very far from ours.

And these are something that we would have called planets back in the day.

But ever since Pluto was demoted...

...they're now called dwarf planets or something smaller.

- Thank God, you're here. - What's the emergency?

I got the Mars Rover stuck in a ditch.

- Where? - On a dusty highway...

...just outside Bakersfield.

Where do you think? On Mars.

Howard is actually not one of the scientists.

Howard is an engineer.

- Dr. Gablehauser. - Dr. Kootrappali.

- Dr. Gablehauser. - Dr. Hofstadter.

- Dr. Gablehauser. - Dr. Cooper.

- Dr. Gablehauser. - Mr. Wolowitz.

So of the four, he's the only that doesn't have a Ph.D.

Which is something which they've pointed out to him...

...and why Sheldon called him one of the Oompa Loompas of science.

A loop counter...

...and an escape to the least objectionable activity.

Howard, that's brilliant.

I'm surprised you saw that.

Gee, why can't Sheldon make friends?

When I first got involved in the show...

...there was only, maybe, one episode out there, just the pilot.

A lot of physicists that approached me were a little bit nervous...

...and they were a little bit afraid that physicists would be portrayed maybe--

Geeks with a kind of mean spirit.

Anecdotal evidence suggests that in a game of Rock, Paper, Scissors...

...players familiar with each other will tie 75 to 80 percent of the time...

...due to the limited number of outcomes.

I suggest, rock, paper, scissors, lizards, Spock.

And now, it's completely changed.

Now that it's been second season, I get nothing but positive feedback.

These are smart people. These are gen--

I mean, we call them nerds because we don't get it.

They're not nerds, they're geniuses...

...who just don't process things the way that normal people do.

- It's fine with you if I'm not smart? - Absolutely.

The response has been overwhelmingly positive by the scientists...

...who love the show, and their husbands and wives...

...I think love the show even more.

- What do you want me to do? - Smile.

PRADY: We had an article about us in Science Magazine...

...North America's leading journal of things scientific.

A lot more exciting than Variety.

Who would think you'd see an article...

...about a situation comedy in a physics magazine?

Comedy is as old as science.

It's interesting that every time I try to think of something funny...

...there's all sorts of scientific reasons why it won't work out...

...that the writers have taught me.