Fifty years ago tomorrow -- on Feb. 20, 1954 -- President Dwight Eisenhower interrupted his vacation in Palm Springs, Calif., to make a secret nocturnal trip to a nearby Air Force base to meet two extraterrestrial aliens. Or maybe not. Maybe Ike just went to the dentist. There's some dispute about this.

The Ike-met-with-ETs theory is advanced by Michael Salla, a former American University professor who now runs the Peace Ambassador Program at AU's Center for Global Peace.

The Ike-went-to-the-dentist theory is advanced by the folks at the Dwight D. Eisenhower Library in Abilene, Kan. And by James M. Mixson, a dentist, professor of dentistry and historian of presidential dental work. Just to make things more intriguing: On the night in question, the Associated Press reported this: "Pres. Eisenhower died tonight of a heart attack in Palm Springs."  Two minutes later, the AP retracted that bulletin and reported that Ike was still alive.

Indeed, Ike was alive. And he continued living until 1969. But in the decades since his death, his activities on the night of Feb. 20, 1954, have become fodder for strange theories about alien beings.

Some facts are beyond dispute: Eisenhower was on a golf vacation in Palm Springs on Feb. 20, 1954. After dinner that night, he made an unscheduled departure from the Smoking Tree Ranch, where he was staying. The next morning, he attended a church service in Los Angeles. Also that morning, his spokesman announced to the press that Ike had visited a dentist the previous night because he'd chipped a tooth while eating a chicken wing at dinner.

Salla, who has a PhD in government from the University of Queensland in his native Australia, doesn't believe it. He figures the dentist trip is just a cover story. He believes Ike went to Edwards Air Force Base, where he met with two ETs with white hair, pale blue eyes and colorless lips.

These aliens -- nicknamed "Nordics" in UFO circles because they resemble Scandinavian humans -- traveled to Edwards from another solar system in a flying saucer and, Salla says, they spoke to Eisenhower.

"There was telepathic communication," says Salla, 45, as he sits in his suburban Falls Church living room. "It's as though you're hearing a person but they're not speaking."

The "Nordics" offered to share their superior technology and their spiritual wisdom with Ike if he would agree to eliminate America's nuclear weapons.

"They were afraid we might blow up some of our nuclear technology," Salla says, "and apparently that does something to time and space and it impacts on extraterrestrial races on other planets."

Ike declined the ETs' offer, Salla says, because he did not want to give up the nukes. Sometime later in 1954, Ike reached a deal with another race of extraterrestrials, known as the "Greys" -- allowing them to capture earthling cattle and humans for medical experiments, provided that they returned the humans safely home. Since then, Salla says, the "Greys" have kidnapped "millions" of humans.

Salla, author of "The Hero's Journey Toward a Second American Century," published his ET theories in his new book, "Exopolitics: Political Implications of the Extraterrestrial Presence" and in an article on his "Exopolitics" Web site.

For much of the '90s, Salla studied conflict resolution and tried unsuccessfully to apply that knowledge to prevent war in East Timor and the Balkans, he says. Frustrated, he began looking for an extraterrestrial connection to human misery and, he says, he found evidence of ET visitations -- including the Ike encounter -- on the Internet.

"There's a lot of stuff on the Internet," he says, "and I just went around and pieced it together."

Meanwhile, he taught at the School of International Service at American University. In 2003 he founded the university's Peace Ambassador Program, described on the AU Web site as a,

"summer program that combines study, meditative practices, and prayer ceremonies at selected Washington DC sites aimed at promoting individual self-empowerment and Divine Governance in Washington DC."

Salla stresses that his ET research is not connected with his work at AU's Center for Global Peace. The folks at the Center for Global Peace are also quite eager to stress that fact.

"The research that Michael Salla is doing is not research that he is conducting on behalf of the center or in collaboration with the center," says Betty Sitka, associate director of the Center for Global Peace. "This is his own personal research."

Meanwhile, the question remains: Did Ike really meet with ETs 50 years ago? "Not to our knowledge," says Jim Leyerzapf, an archivist at the Eisenhower Library. "There's nothing in the archives that indicates that." Then Leyerzapf bursts out laughing. He has heard this theory before. "We've had so many requests on that subject that we have a person who specializes in this."

That person is archivist Herb Pankratz.

"He specialized in transportation," Leyerzapf says, "and we decided to add UFOs to that. He does trains, planes, automobiles -- and flying saucers."

The library fielded dozens of questions about the alleged Ike-ET meeting in the late '80s and early '90s, when several UFO books advanced the theory, Pankratz says.

"It's interesting how these stories have changed," Pankratz noted in an e-mail. "Initially, the accounts claimed the President made a secret trip to Edwards Air Force Base to view the remains of aliens who had crashed at Roswell, N.M., in 1947. Later stories then claimed he had actually visited with live aliens."

Pankratz doesn't buy either theory. He believes the dentist story, and he cites James Mixson, the dental historian and professor at the University of Missouri-Kansas City School of Dentistry. Mixson's article "A History of Dwight D. Eisenhower's Oral Health" -- published in the November 1995 issue of the Bulletin of the History of Dentistry -- is the definitive work on Ike's teeth.

Citing the U.S. surgeon general's records on Ike's medical and dental history, opened to researchers in 1991, Mixson reported that on the fateful night of Feb. 20, 1954, Ike chipped the porcelain cap of his "upper left central incisor" and it was repaired by Dr. Francis A. Purcell. Alas, Purcell is unavailable for comment. He died in 1974, according to Pankratz.

"The lack of a dental record from Purcell's office," Mixson wrote, "has helped fuel belief in this UFO encounter." But, Mixson quickly added, "the President had well-documented difficulties with this crown."

Indeed, the crown, which was installed in July 1952, was chipped and repaired in December 1952, the February in question, and again in July 1954, when the president's dentist, Col. James M. Fairchild, replaced it with a "thin cast gold/platinum thimble crown."

That may be more than you wanted to know about Ike's dental work. If not, Mixson goes on at some length, quoting a long, lyrical passage written by Fairchild on this troublesome presidential incisor. Meanwhile, there's another perplexing question: Why did the AP report that Ike died that night?

"Somebody was fooling around and it went out," Pankratz says. "It wasn't supposed to go out but it did."

Ike never made any public statement about meeting ETs, Pankratz says. But did he perhaps spill the beans to his family? Ike's son, John S.D. Eisenhower, is a retired Army brigadier general and author of several books on history, including "General Ike: A Personal Reminiscence." Asked via e-mail if his father had ever mentioned meeting with aliens, Eisenhower responded with a short but emphatic reply: "No." He declined to comment further.