Through the combined efforts of a Polish pope and a priest whose order was founded to root out heretics, the Roman Catholic Church is ready to concede officially that the earth revolves around the sun.

The signal came in the Vatican's announcement yesterday that the 17th century heresy trial of Italian astronomer Galileo Galilei will be reopened. c

The decision was made at the express wish of Pope John Paul II, whose fellow Pole, Nicholas Copernicus, was the first Renaissance astronomer to speculate that the earth was not the stationary center of the universe, a highly heretical thesis for which Galileo provided the mathematical proofs. "Still, it moves," muttered Galileo after recanting to avoid the death sentence by the Inquisition.

John Paul's motivation was not simply to exonerate the most important figure in Polish intellectual history, implicitly condemned along with Galileo. The pope's action is also designed to wipe out a judgment that in living memory was being used by adversaries of the church as a symbol of its opposition to intellectual freedom.

John Paul said last year that Galileo had been wrongly condemned, but bringing the church to reopen the trial held in 1633 was the culmination of a campaign begun when Emperor Napoleon made off with the treasures of the Vatican -- including the official transcript of the trial. Putting Galileo in the dock was the antithesis of the French Revolution's rational creed, in the name of which Bonaparte conquered Europe.

The record of the trial remained in France for two decades. After the revolutionary wave had spent itself, the restored French monarchy returned it to the Vatican with condition that facilitates reopening the trial -- French scholars were to be allowed free access to the documents.

So it was no accident that a French priest, the Rev. Dominique Dubarle, should lead the latest campaign to clear Galileo.Appropriately, he is a Dominican. The Dominican order supervised the Inquisition and has perceived a responsibility to wipe out the stain on its record.

Dubarle, also an atomic scientist, appealed during the Vatican II Ecumenical Council in the early 1960s for the then pope, JOHN XXIII, to accept a retrial to "reconcile the Catholic Church with science." Dubarle had first broached the idea to the pope during the years that he was the papal nuncio, the Vatican's ambassador, in Paris.

Using his rights as a French scholar, Dubarle studied the record in the Vatican Library, and worked out a set of arguments for Galileo based strictly on canonical law. But pope John, who had opened the windows of the church to the modern world, had died by the time the brief was ready for submission. His more cautious successor, Paul VI, would not follow the course advocated by Dubarle.

Friends of the priest said that Dubarle, now 75 and ailing, recounts how distraught he was by Paul's attitude. But, as a teaching priest at the Catholic Institute of Paris, he submitted to discipline.

Yet Dubarle did not give up hope. The international vice president of the Pugwash Conference international discussion group, Dubarle continued to work for the causes he believed in -- such as the reconciliation of the German and Polish Catholic churches. In that role he served as the intermediary between then Cardinal Karol Wojtyla, now the pope, and his West German opposite number.

Dubarle was also a major figure in the movement to get the church to revise portions of the liturgy that provided a theological basis for anti-Semitism. During World War II, the Nazis had expelled him from a French prisoner-of-war camp -- and into the French Resistance -- because as the prisoners' elected representative he was making it too difficult for the captors to treat Jewish POWs differently from the others.

So Galileo's posthumous victory over the remnants of medieval obscurantism also will be a victory for a dedicated 20th-century priest who is now paralyzed in a Strasbourg hospital after a life of working for a church stripped of impediments with the rest of a world that has continued to turn.