Why One Big Bang Theory Mystery Will Never Be Revealed

Johnny Galecki Leonard Hofstadter Kaley Cuoco Penny The Big Bang Theory CBS

The Big Bang Theory is ending after Season 12, and it will end with at least one mystery intact. Here's a list of the main characters on the show. See if you can spot what's missing:

• Leonard Hofstadter (Johnny Galecki)• Sheldon Cooper (Jim Parsons)• Penny (Kaley Cuoco)• Howard Wolowitz (Simon Helberg)• Rajesh "Raj" Koothrappali (Kunal Nayyar)• Amy Farrah Fowler (Mayim Bialik)• Bernadette Rostenkowski-Wolowitz (Melissa Rauch)• Stuart Bloom (Kevin Sussman)

Everyone has a last name, except for Penny. Technically she does have a last name now -- Leonard's last name Hofstadter.

The Big Bang Theory had a WonderCon panel on Saturday, and a fan asked if viewers would ever learn Penny's maiden name. That's a negative, and Executive Producer Steve Molaro explained why:

[Eventually] we got nervous and superstitious about giving her one. It will always be [her married name] Hofstadter.

So they went long enough with Penny just being Penny that they decided it would be bad luck to make her Penny Such-and-Such until she married Leonard in Season 9 and became Penny Hofstadter.

Kaley Cuoco recently revealed she was originally rejected from The Big Bang Theory, back when the role as conceived as a girl named Katie, because she was considered too young. The role was revised to be the Penny fans know and love, but without ever adding a second name.

They could've revealed Penny's maiden name along the way, since we did first meet her father Wyatt (Keith Carradine) in Season 4 and that would've been an easy way to slide in new intel. In fact, that had come up before, when a fan asked in 2009 if we'd ever meet Penny's family and tell the fans her last name. The answers at the time were "yes and yes" but the second "yes" will apparently not happen after all.

Of course, fans also asked if the elevator would ever be fixed. That's something that Kaley Cuoco herself has brought up as something she'd like to see solved by the finale. No promises on that, but it's possible.

The Big Bang Theory finale will air May 16, but they actually shoot the series finale on April 30th, which is Kunal Nayyar's birthday. So they have less than a month to film the rest of the season.

Executive Producer Steve Holland talked more about the endgame plans during the WonderCon panel (via THR):

In a lucky way, we knew it was the final season pretty early … it gave us a lot of time to talk about where we wanted to leave these characters. That [work] was able to push some of [the emotion] off. Now we’re getting closer and closer, and it’s [hitting us that it's] the last time we’re going to do this or that.

Wil Wheaton moderated the WonderCon panel, and he previously said he figured he was done on the show after his most recent episode. We'll have to wait and see if that's true. There's going to be a lot of emotion on-and-off screen as the show readies to say goodbye. Kaley Cuoco already has a plan for what she wants to take from set, and how she wants to honor the show in a year or two.

The Big Bang Theory Season 12 has been on pause for nearly a month, which is kind of frustrating considering it's the final season. But it will return with new episodes starting this week with Episode 18, "The Laureate Accumulation," which airs Thursday, April 4 at 8 p.m. ET on CBS.

Gina Carbone

Gina grew up in Massachusetts and California in her own version of The Parent Trap. She went to three different middle schools, four high schools, and three universities -- including half a year in Perth, Western Australia. She currently lives in a small town in Maine, the kind Stephen King regularly sets terrible things in, so this may be the last you hear from her.