With its image of blue sky and fluffy clouds, the rectangle floating lately over I-95 near Allegheny Avenue suggests something dreamy, almost heavenly.
At least from a distance.
Drivers headed north toward the giant billboard might first discern the words God and Believe and suppose this to be the work of a fundamentalist church.
But this is the work of no church.
"Don't believe in God?" it asks. "You are not alone."
Think of it as a sign of the times.
Mounted by a consortium of local atheists, it is an invitation to the area's atheists, agnostics, skeptics, rationalists and religious freethinkers (no one label fits them all) to overcome their differences and form a coalition.
"Hundreds of thousands of your neighbors in the Delaware Valley feel the same as you do," according to the Web site www.phillyCOR.org, to which the billboard directs passing motorists.
"Our mission is not to convince fundamentalists to change their position," Steve Rade, a Huntingdon Valley businessman, said last week. He donated the $22,500 needed to mount the billboard, which appeared May 1 and is to remain until the end of August.
"What we want to do is give people questioning their beliefs a place to go for more information and to meet like-minded people."
No horns poke through Rade's wiry gray hair. He is tall and bony, quick to laugh, and dressed for the office - he is president of Wireless Accessories Inc. - in shorts and sneakers. He has the restless energy of a teenager. He is 70.
"I'd like everyone to believe what I do," he said, referring to his "absolute certainty" that there is no divine being running the universe and no life after death. "I think it would be a better world if they did."
The son of a West Oak Lane synagogue president who insisted that his children attend Shabbat services every Saturday, Rade was bar mitzvahed at 13 and confirmed at 16. But his youthful doubts about God and supernaturalism hardened while an undergraduate at Pennsylvania State University, where he was a finance major.
"It was just my own critical, rational thinking," he said Thursday with a shrug. "I accept that the universe began with the Big Bang, but I don't believe there were snakes talking in the Garden of Eden. . . . If God shows himself to me, I'll believe."
His grand plan - organizing the region's religious skeptics - began just three months ago, when he asked the American Humanist Association in Washington how to find its local chapter.
In March, he met for dinner with Joe Fox, president of the Humanist Association of Greater Philadelphia. Fox told him that there were many atheist groups in the region, but that few communicated with one another.
"Joe saw it as a lack of focus," Rade recalled. "I saw it as disarray."
Days later, he invited Fox and the heads of seven other like-minded organizations to dinner at a Chinese restaurant and asked if they wanted to expand and unify.
They agreed to create an umbrella group called the Greater Philadelphia Coalition of Reason (PhillyCOR), and Rade agreed to pay the salary of its half-time executive director.
After that, "the idea for a billboard was easy to come by."
The 20-by-60-foot sign has generated 7,000 hits for the Web site, which offers links to such member organizations as the Humanist Association of Greater Philadelphia, the Freethought Society of Greater Philadelphia, Philadelphia Atheists Meetup, and the Secular Society of Temple University.
The sign's original, geographically limited toll-free phone number generated only about 300 calls, however. The new number, 1-877-99HUMANIST, is reachable from any area code.
A recording describes PhillyCOR as a "local free thought group" for "those without supernatural beliefs."
"I'm so appreciative of Steve," Sally Cramer, president of the 300-member Freethought Society, said Friday. "I love the message. I'm really pleased we're able to be a part of this."
At age 24, she has no way to know if it is easier for today's atheists to be "out of the closet," but she said she had encountered hostility. The mother of a previous boyfriend "wouldn't talk to me when she found out I'm an atheist," she said.
No one knows how many American adults identify themselves as being in the atheist spectrum, but surveys suggest between 4 percent and 9 percent, the lowest of any industrialized nation.
Fred Edwords, spokesman for the roughly 10,000-member American Humanist Association, said he thought it was easier for atheists and agnostics to be public than in previous decades.
"In the 1980s, people were saying we're part of a great conspiracy, trying to take over the schools and courts."
The recent spate of best-sellers bearing such titles as The God Delusion, God Is Not Great and The End of Faith suggests a broader public interest in religious skepticism, Edwords said. "But we still feel we're the last minority group it's OK to say bad things about."