It’s the Big Bang and then some at the American Museum of Natural History tonight. All 924 seats in the Hayden Planetarium’s LeFrak Theater are booked out, and two adjoining auditoriums with video screens will be thrown open as an overflow crowd goes searching for nothing less than signs of intelligent life in the universe.

Welcome to the sixth annual Isaac Asimov Memorial Panel Debate, in which a panel of leading astrophysicists and cosmologists will argue the possibilities of multiple universes and unknown dimensions. These are hot topics in cosmology – and a mindstretch for those who have even a working knowledge of the Big Bang and what lies beyond.

This year’s panelists include Michio Kaku of City College, CUNY, author of “Parallel Worlds”; Lisa Randall of Harvard University, author of “Warped Passages: Unraveling the Mysteries of the Universe’s Hidden Dimensions”; Lawrence Krauss of Case Western Reserve University, author of “Hiding in the Mirror: The Mysterious Allure of Extra Dimensions”; Andrei Linde of Stanford University, a theoretical cosmologist who is one of the original architects of the multiverse concept, and Virginia Trimble, a professor of astronomy at the University of California, Irvine.

“People want to know whether or not we’re alone,” an astrophysicist and director of the Hayden Planetarium, Neil deGrasse Tyson, who is moderating the debate, said. “The public has a great appetite for all things cosmic. There’s also a great curiosity about what happens on the scientific frontier.”

His panelists agree. “Ever since humans first looked up at the night sky and wondered what it all means, they have wanted to know what’s up there, and now science is giving us for the first time, tangible numbers,” Mr. Kaku said. He said he believes our “multiverse” is much like a “soap bubble that is expanding, and may coexist with other bubbles or universes floating in a much larger arena of 11-dimensional hyperspace.”

With a spirited discussion looming about other hotly debated theories, such as the “weak-gravity universe,” attendees are advised to fasten their seat belts. “Gravity is strong somewhere else, but weak where we are,” said Ms. Randall, a high-flying Harvard professor who has opened new frontiers as a model builder, tying together ideas from particle physics and cosmology to define the rubric of extra dimensions of space. “The energy of space warps space-time so much that gravity gets concentrated in another region and is weak everywhere else.”

Ms. Randall blames Albert Einstein and his General Theory of Relativity. “Einstein talked about warped geometry in the context of explaining gravity in the concept of curved space-time; however the particular warped space time geometry we found was very new,” she said.

Ms. Randall said she didn’t anticipate becoming a scientist. Yes, she had read Asimov and the works of other science fiction writers, but she also enjoyed Jane Austen. She predicted that in our lifetime, “We may understand what gives particles their mass and causes weakness of gravity, beyond that, I can’t tell you.” The Harvard professor is skeptical about more exotic theories of multiple or parallel universes.

The annual debates are inspired by, and in honor of, the prolific author Isaac Asimov, with proceeds benefiting the Hayden Planetarium’s scientific and educational programs. Asimov, author of “The Foundation Series,” “I, Robot” and other classic works of science fiction, died in 1992, having published more than 500 books.