UNITED NATIONS — There is no U.N. special envoy for space aliens, let’s get that straight from the outset, nor even an official designated to pick up the phone should one call.

It is true, however, that a U.N. Office for Outer Space Affairs sits in Vienna. (No, it has nothing to do with amorous astronauts, either.) Its task consists basically of monitoring or refereeing cosmic matters — space debris, for example, or maintaining a list of about 3,000 objects sent hurtling into orbit in the past roughly 50 years.

Until this week, one could argue that with the exception of the scientific community, the office was more obscure than outer space itself. But it has been thrust into the limelight by a scientific conference in Britain whose panels included space-related topics like "Calling ET, or Not Even Answering the Phone?" and "Extraterrestrial Life and Arising Political Issues for the U.N. Agenda."

The idea, basically, is that one day, maybe soon, some manner of life or maybe a signal will materialize from another galaxy far, far away. How should earthlings react? Might, for example, the United Nations be designated the spokesman for the entire planet if Darth Vader comes to call?

The conference organizers totally dismissed that latter possibility.

"It is not the little green man in the flying saucer — that is the wrong image," said an organizer, Martin Dominik, a physicist at the University of St. Andrews.

What is meant, he explained, were microbes, or perhaps an electronic signal.

"There could be interaction between life on our planet and life elsewhere so how do we deal with that," Dominik said, warming to the topic.

What if the microbes are harmful, for example, or the signal hostile?

"The question is should we send messages into outer space or not?" Dominik added. "Is this dangerous? Should we make ourselves visible to extraterrestrial life or not? If they know we are here, do they want to destroy us, will they help us, do we gain something from that? These are all open questions."

The issue becomes more pressing as knowledge of other planetary systems expands and radio telescopes can beam ever more powerful signals into the void. The United Nations could play a valuable role, Dominik and others noted, in preventing a single nation, or perhaps, the U.S. military from hogging the dance card of the first alien, even if it is a microbe.

Not that the United Nations will take a position, exactly. The secretary-general, Ban Ki-moon, refused to comment.

"There is no United Nations position on extraterrestrial life," said Mazlan Othman, the Malaysian astrophysicist who runs the Office for Outer Space Affairs. ("I am not the ambassador to aliens!" she said.)

There is also a certain recognition that since the 192 U.N. members are generally incapable of reaching agreement on pressing earthly matters like climate change, negotiating a protocol for alien encounters will be one long slog.

The discussion on coping with a threatening asteroid collision has been grinding on in a subcommittee since 1999, Othman noted.

"To get consensus on anything at all is difficult at the United Nations — water, peacekeeping, it is not just extraterrestrials," she said.