But what if a meteor was on a collision course with Earth?
"If it did happen, we would just blow up, right?" Gloria Hickey, 10, asked.
"It depends on the mass," said Alice Monet, a retired U.S. Navy astronomer. "This is very unlikely. Very unlikely."
But Gloria appeared unconvinced.
"I want to make it to 11!" she said.
Monet, who worked at the U.S. Naval Observatory for 35 years, repeated that being struck by a meteor big enough to blow up the planet was unlikely. A comet whipping through the cosmos, on the other hand. . . .
The group, made up of fifth-graders from Taylor Elementary School, a sixth-grader from Swanson Middle School and the students' parents, is a new book club. Its members call themselves RAAKstars, for Reading Adventures for Adults and Kids.
This month's selection was "George's Secret Key to the Universe," by Lucy and Stephen Hawking. Monet, the club's guest speaker, led a discussion at the Clarendon Barnes & Noble on Feb. 10.
"I always thought the universe was too far out there for us to reach," said Robby Gessel, 10. "Scientists have gotten further than I thought they ever could."
The students discussed technology, Newton's laws of motion and how cool it would be to have a portal to space in their home. Some held sidetrack chats about tasty vegetables and whether computers could rot a brain.
All of the kids love to read. Julia Fayer, 11, reads so many books, "she could eat them," she said. To avoid losing a small fortune, Julia gives her library card a workout, said her mother, Daniela Fayer.
"At this age, they don't want to do anything with us. . . . This gives us something to talk about," said Fayer, who added that she had learned a few things from the Hawkings' book.
The club's organizer, Brig Pari, got the idea for it when her son's school, Taylor Elementary, was reading a young reader version of Greg Mortenson's "Three Cups of Tea." The school's PTA gave students copies and the school collected $2,400 in pennies for the author's Penny for Peace organization, which builds schools in the Middle East.
Pari wanted the book club to include speakers to further what the youngsters learned by reading.
Next month the club members will discuss "Percy Jackson and the Olympians - The Lightening Thief" by Rich Riordan. The guest will be Charles McNelis, a Georgetown University classics professor.
"Instead of just reading what the author put down, you talk to somebody who actually knows about it," Michael Pari, 11, said.
Julia said she likes that she can ask experts a question, "and they can answer it better than your parents."
Monet, president of Friends of the David M. Brown Planetarium, which has raised about $280,000 toward saving the facility, said she had a great time speaking with the club members.
"They were articulate. I don't think anybody held back," Monet said. "Their questions were not just about what they read but had gotten them thinking. That was very sophisticated."