The recent discovery of an Earthlike - if searingly hot - planet far from our solar system reminded many that our dreams of space live on. Even with shrinking science budgets and no cold war to spur things on, visionaries throughout the international space community continue to muse about extraterrestrial life, interstellar probes and long-range missions to other worlds.

Some would even skip the inconvenient second half to President Kennedy’s famous challenge “of landing a man on the Moon and returning him safely to Earth.” Send astronauts to Mars, they argue, but don’t worry about returning them safely.

Lawrence M. Krauss, a theoretical physicist and author of “The Physics of Star Trek,” wrote in an essay for The New York Times that the combined weight of fuel and shields needed to protect astronauts from the sun’s radiation while in space could prove prohibitive for many decades to come. But if astronauts, especially older ones, are willing to die on Mars, the high cost of a round-trip mission would no longer be an issue.

As for volunteers, Dr. Krauss wrote of an unofficial poll of scientists at the Jet Propulsion Laboratory in Arizona. “Every member of the group raised his hand” when asked if he would sign up for a nine-month, one-way journey to Mars.

The possibility of finding life in other solar systems continues to fire imaginations, and not just in Hollywood. Alan Boss, an astronomer and theoretical physicist, told The Times’s Claudia Dreifus that “life on Earth is so vigorous and so able to thrive and fill every niche, how could it not be elsewhere?”

He is not giving much thought, however, to aliens - whether hostile or friendly - visiting us. “Distances between stars are so immense,” he told Ms. Dreifus, “that there’s zero probability that anybody could come here to invade.”

But even interstellar travel may be moving from the realm of science fiction to plausible science theory. Seth Shostak, an astronomer and author, argued in a Times opinion page article that with atomic rocket engines - which were banned from space in the 1960’s - a robot craft could leave the Earth later in this century and beam back detailed images and data in the middle of the next. A conventional rocket would take 800 centuries to reach a nearby star.

Meanwhile, the search for extrasolar planets continues. On September 16, scientists at the Thuringer observatory in Germany reported finding the most Earthlike planet yet. Unlike the 300 gaseous, giant planets discovered so far, this one, named Corot-7b, is rocky and only 1.5 times larger than Earth. With its 1,980 degree Celsius temperature, however, it is not a good candidate for a one-way trip.

But if a better candidate and a faster way to reach it is discovered someday, those suicidal space volunteers may not be considered quite so eccentric.

As Dr. Krauss wrote, “Give us a century or two and we might turn the whole planet into a place from which many people would be happy to depart.”


Some scientists say that they would be willing to live, and even die, on Mars.


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