Gas fuels the motorcycles as they enter the arena, the sound of their engines slapping the air.
The power comes from the basic internal combustion any mechanic learns on the first day of training. It's a fairly simple reaction.
But what fuels the men and women on the motorcycles as they steer their two-wheelers into a 16-foot metal sphere known as the globe of steel? At first guess, you think insanity. What else, you wonder, prompts a person to engage in this mind-numbing display of centrifugal force, defying gravity by going around and around inside the ball.
They must be crazy, right?
No. The science the Torres Family will exhibit during the Ringling Bros. and Barnum & Bailey Circus at the Tampa Bay Times Forum Wednesday through Sunday stands as a more complicated formula. It's unmeasured doses of adrenaline and trust and practice and courage and knowledge.
But it's not insanity.
Most of all, it's the sound of cheers — adults and kids (especially the kids) wildly clapping and whistling — that propel the riders to whiz around inside the ball, taking on real-life challenges by replicating a toymaker's creation.
Like Lady Gaga, they live for the applause.
"The people give us the courage," said Angelo Fuentes, a Torres cousin and one of the daredevils who will perform in the shows. "When we hear the people scream, it's our gasoline."
Ringling talent director David Kiser says the passion that drives the Torres Family lives in almost every circus performer. The instant gratification they get from the audience lights an internal fire that can't be extinguished.
"It's the reason they push the envelope, the reason they perform and put their life on the line every show," Kiser said. "It's the reason they take the risks that they do."
But couldn't they draw cheers by singing karaoke in a crowded bar, or playing softball or soccer in an adult league before a smattering of fans?
Of course not. They deliver thrills and chills to the crowd because that's what they want in return, the goose bumps that rise when the ovation echoes in an arena normally dominated by music and sports superstars.
"When the fans start clapping, you never feel more comfortable," Ariel Torres said. "You don't think scared."
Torres, 43, first engaged in this fearless practice 17 years ago. A motocross rider, he witnessed a show in Argentina and said, "I have to do that."
Now, according to circus officials, the Torres Family holds the record for most motorcycles in a 16-foot sphere with eight — all speeding in a circle at 75 miles per hour.
Others have had more riders, but the sphere is larger.
Such feats don't occur without practice. Fuentes said on days they don't have shows — and sometimes they do three shows in a day — practice will run for two hours. The feats require an immense amount of coordination and timing, but even with precision, the risks remain.
"There is an absolute element of danger they can't control," Kiser said.
Like any circus act, the Torres Family continues to seek and find new ways to add to its act. Torres says they have a "big surprise" for the public.
The latest feat may be so death-defying you may hold your breath. You may be afraid to look. But don't cover your eyes with your hands. Keep clapping.
The Torres Family needs the fuel.
That's all I'm saying.