Late Saturday morning, Neil deGrasse Tyson dominated a cozy panel before an audience of 250 at the Horton Grand Theatre, just down the street from the San Diego Convention Center as one of San Diego Comic-Con’s offsite ticketed presentations. As “Game of Thrones” and “Star Wars” artist Rob Prior worked on a painting of Tyson, Len Wein (co-creator of the Swamp Thing, Wolverine and the New X-Men),  Tyson, Bill Prady (co-creator, writer and executive producer of “The Big Bang Theory), and Peter S. Beagle (The Last Unicorn”) discussed how one goes about creating believable universes in a world where man has walked on the moon and in the next few decades, is determined to set foot on Mars.

Spoiler alert. This article may jeopardize your childhood memories of Mary Poppins and Superman.

After introducing the panel, Wein opened the talk with a statement: “The only thing more vast than the universe is human curiosity.”

Prady cracked that in reality it was human stupidity, but Tyson contended using “human” was problematic because it “shows the hubris of our species to suggest that our curiosity is somehow some supreme measure of interest and complexity” because it “doesn’t recognize the possibility of vastly more intelligent alien species who would look upon us as though we were worms.” Instead, he suggested using “dimensions of imagination undreamt of.” He wanted to allow that so “we don’t think too highly of ourselves; that’s just part of the cosmic perspective that we’re all worth nothing.”

Beagle related that he used to sing a song about an alien coming to earth and discovering that he’s on the wrong planet, but saying he’ll be back, perhaps when we’ve become more interesting. Tyson quipped, “In other words, there’s no intelligent life on earth?”

To which Prady added, “Not in this election season.”

Tyson commented that the question reminded him of King Alphonse X of Spain who commented that if he had been around at the time of creation, he would have given the Lord a few suggestions. He went on to say, “In astrophysics graduate school one of the fun early calculations you do is ask yourself; ‘What would happen if I changed slightly one of the fundamental constants of the nature?'” In the end one realizes that, “the universe we occupy works for us and you start messing with it, there’s not telling what unintended consequences would derive from it.”

Wein recalled that a fan once queried about Nightcrawler’s ability to teleport, and Wein replied, “You know for me, it works for me because I say it works.” Nightcrawler is a mutant member of the X-Men who is super agile, can teleport and has adhesive hands and feet. In the 2003 movie, “X2: X-Men United,” he was portrayed by Alan Cumming.

Tyson noted that at SDCC, “You have this intellectual resource of hugely creative people who will fill in all those gaps.” He recalled a Twitter tussle about light sabers. “If light sabers were actually made of light, they would just pass through each other,” he explained. It would essentially be like two flashlights and not very exciting. Another physicist eventually suggested gamma rays which would interact with each other. but Tyson noted that gamma rays wouldn’t be visible to your eyes.

That might be possible, Tyson was willing to concede but he also noted that lasers as weapons would be hard to dodge. “When you fire lasers at people, you cannot duck because you cannot see light coming toward you until the light hits your eyes and then  you’re dead.”

Beagle recalled when he was working on a project with Isaac Asimov, “I made a change. I called Isaac in New York to read it to him. I asked, ‘Would it be feasible?’ He said, “Absolutely not. Now, what we have to do is make it plausible.”

In creating universes, the panel discussed different approaches. There’s the Spiderman approach where you can claim a bite from a radioactive spider makes changes at the DNA level, but there’s also the Dr. Who approach.  Wein noted, “If you assume Time Lords and tardises and things like that you assume some things human beings wouldn’t be able understand.”

Tyson commented, “I like that fact that you can just create things,  that stuff goes on and it’s natural for them. It’s like ‘It’s bigger on the inside.’ It’s like a mantra. That’s what gives us evidence to makes us pretty sure that Mary Poppins was a Time Lord” because “from her bag she reaches out and pulls out entire lamps.” While other characters are initially stunned, they celebrate the fact she has those powers and we don’t.

Other panelists were not so sure about that. In real life, one panelist suggested you might scream.  From Mary Poppins, the discussion turned to Superman. “The goal from a fantasy point of view is that he exists in our world,” Prady contended. During the first season of “The Big Bang Theory,” the guys look at the Lois Lane problem from the laws of physics. The scenario is Lois Lane is falling from a great height. She’s falling, she’s building up velocity.

Superman may have arms of steel, but Lane is just human flesh and bones. Prady insisted that If she fell and was building up velocity and Superman sticks out his two arms of steel, she is trisected. “His best move is to use his heat vision and kill her.”

Tyson noted the same thing happened in The Matrix series.  Neo comes to save Trinity.

Prady argued that Superman would at some point brake her, although after initial confusion Tyson made sure it was “brake” instead of “break.”  Superman would have to match her speed and eventually stop her. Another suggestion: Superman’s arms were super shock absorbers.

Then the conversation took a turn for a little intellectual gutter humor. Tyson remembered how someone called in to his Star Talk program and asked if “Superman has super flatulence.” That got Tyson to thinking.  “Methane is flammable. If it’s super then he has super methane ” Superman also has heat vision and that would mean Superman has a new weapon: flaming farts because he could “ignite his farts with his x-ray vision.”

Prady imagined Superman talking to Lois Lane, saying, “I can get us out of here, but you’re never going to look at me the same way again.”

Beagle interjected, “If you’re good enough, anything works.” But the other panelists noted that’s a big if. From the DC Comic world of Superman, the conversation veered into Star Trek. If you recall that episode “Operation–Annihilate,” Spock volunteered for an experimental treatment which used bright light to kill a parasite found on the Deneva colony. The light blinded him, but further tests indicate that the blinding light wasn’t actually necessary because the parasites were actually killed by ultraviolet light. McCoy realizes that Spock didn’t need to be blinded. Yet at the very end of the episode, Spock returns to the bridge; he can see again because Vulcans have an inner eyelid. Tyson noted one doesn’t forget one has an inner eyelid and then suddenly remember.

Prady noted a more important fact, the first question you need to ask when you turn up somewhere is: “Do you have a Spock and does he have a beard?” (See “Star Trek: The Original Series” episode “Mirror, Mirror.”)

More seriously, Prady explained that “iIf the laws of the universe are inconsistent in the world you’ve created, you never know if your characters are going away from or toward danger.” For his characters in “The Big Bang Theory,” he doesn’t want them to make a discovery because that would have real world complications.

On a more serious note, Beagle  commented that he wanted to make his world as realistic as possible. The world has to have rules. Yet sometimes those rules change. “Long ago, everything was fantasy. People believed firmly in dragons. People believed in witches. The people in the next village talked funny and were probably demons.” Beagle continued by saying that in Mark Twain’s  “The Adventures of Huckleberry Finn,” Huck “firmly believes he’s going to hell” for helping the slave Jim to escape. That’s a grand moment in literature, but Beagle contends there’s an even better moment when Huck gradually realizes that black people feel about their children the same way that white folks do. It doesn’t seem natural to Huck at first, but he reckons it is so. Such a revelation of what is natural or seems natural in one’s world can be vast.

After applause and a brief lull, the conversation picked up about creating of worlds and creating emotional connections.

Prady said think about Star Trek. “The Enterprise arrives at a planet and it’s a primitive culture.” The problem becomes: How do you put the crew in jeopardy? You don’t want to always pit the crew against superior beings. That is why Superman has kryptonite.

There are other ways of compensating. In the case of Wolverine, it’s emotional angst and even anger management.

Tyson noted the recent “The Martian” was “a first on many fronts” because “the suspense, the anguish, the love, the hate, the desire were all filtered through the lens of science, engineering and technology–not through interpersonal relations.” Tyson noted usually “the familial connection” the most important aspect. In “The Martian,” the question was not will he return to his loved ones, but: “Is he clever enough to not die?” Tyson continued, “The love was the love of science; the suspense was: Will it work?”

Wein noted, “I’ve always felt that way about MacGyver.”

Prady noted that when you have devoted fans, there’s something of a covenant where “we promise to lie really good and consistently.” When that isn’t done, the reaction can be harsh. Prady recalled when the writers forgot they had already given a name to Penny’s father and when they finally decided to have him appear, they mistakenly gave him a different name.

A similar problem happened with “Star Trek: The Original Series” when James Kirk was given the middle initial of “R” in “Where No Man Has Gone Before” although later it was made clear that his full name was James Tiberius Kirk.

That’s the problem with continuity of storytelling and creating universes: being consistent and remembering all the details. Yet people still love Star Trek despite the mistakes and such things become fodder for trivia games.