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Stephen Hawking: The Future of Space -Manned vs Robotic Missions?

In astronomy, extraterrestrial, sci-fi, technology on March 7, 2010 at 4:06 pm

“Robotic missions are much cheaper and may provide more scientific information, but they don’t catch the public imagination in the same way, and they don’t spread the human race into space, which I’m arguing should be our long-term strategy. If the human race is to continue for another million years, we will have to boldly go where no one has gone before.”

Stephen Hawking, Cambridge University

Will unmanned robotic missions be able to detect weird microscopic life-forms they are not programmed to recognize that might be lurking below the surface of Saturn’s Titan, or beneath the murky seas of Jupiter’s jumbo moon, Europa?

The answer to this question is at the core of one of the greatest of the ongoing debates in space exploration: the question of man vs. unmanned robotic missions.

NASA currently operates more than 50 robotic spacecraft that are studying Earth and reaching throughout the solar system, from Mercury to Pluto and beyond. Another 40 unmanned NASA missions are in development, and space agencies in Europe, Russia, Japan, India and China are running or building their own robotic craft.

What is not commonly known however is that many of NASA’s leading scientists also champion human exploration as a worthy goal in its own right and as a critically important part of space science in the 21st century. The Obama administration’s new NASA strategy that strongly favors robotic exploration, has opened the debate anew.

In a past issue of Scientific American Jim Bell, an astronomer and planetary scientist at Cornell University, and author of “Postcards from Mars,”  notes that “…you might think that researchers like me who are involved in robotic space exploration would dismiss astronaut missions as costly and unnecessary.”

But he then he goes on, “Although astronaut missions are much more expensive and risky than robotic craft, they are absolutely critical to the success of our exploration program.”

Astroboy171104_2The heart of the debate is this: robotic machines will only do what they are programmed to do; they are not programmed to detect weirdness: the unimaginable, the unknown, the strange non-carbon life that we may have encountered on Mars, for example with the two Viking vehicles, in 1976. Each carried equipment for sampling the Martian soil and miniature chemistry laboratories to test the samples for signs of life.The results these automated labs radioed back to Earth were enigmatic: the chemical reactions from the Martian soil were strange, unlike anything seen on Earth. But they were also unlike any reactions that living organisms would produce.

Ben Bova, the science-fiction author of Titan and The Aftermath, his most recent novels in is his ongoing series about the expansion of the human race throughout the Solar System, points out in an interview that most scientists examining the Viking results, reluctantly concluded that was lifeless: “But the fact is that the landers were equipped only to detect signs of Earth-type life. The chemical reactions observed could have been the results of Martian life. They certainly were not ordinary inorganic chemistry.”

The debate over the meaning of the Viking results, Bova concludes, is still unsettled, more than 30 years later. But a human biologist or biochemist could have learned a lot more and settled the matter, one way or the other, within a few hours.

What are we looking for, exactly, when we search for alien life? That’s the cosmic question pondered in the report from the National Research Council, The Limits of Organic Life in Planetary Systems. For more than five years, a committee of scientists tried to imagine what life-as-we-don’t-know-it might be like. Their conclusion: Life may exist in non-carbon forms completely unlike anything we see on Earth.

The human vs.machine debate is a false construct: robotic unmanned spacecraft are directed by human beings on Earth. Unless disabled by fierce sandstorms, our rovers are in constant realtime communication with their masters at the Jet Propulsion Laboratory, as will the New Horizons spacecraft now heading for Pluto with human monitors watching over it.

Stephen Hawking, world-celebrated expert on the cosmological theories of gravity and black holes who holds Issac Newton’s Lucasian Chair at Cambridge University, has strong views on the future of the human species and space trael. At last year’s 50th anniversary for NASA. Hawking proposed that the world should devote about 10 times as much as NASA’s current budget – or 0.25% of the world’s financial resources – to space exploration. Hawking backed the space agency’s goals of returning astronauts to the Moon by 2020 and sending humans to Mars shortly after that.

The Moon is a good place to start because it is “close by and relatively easy to reach”, Hawking said. “The Moon could be a base for travel to the rest of the solar system,” he added. would be “the obvious next target”, with its abundant supplies of frozen water, and the intriguing possibility that life may have been present there in the past.

“A goal of a base on the Moon by 2020 and of a manned landing on Mars by 2025 would reignite the space program and give it a sense of purpose in the same way that President Kennedy’s Moon target did in the 1960s,” he said.

Hawking said that any long-term site for a human base should have a significant gravity field, because long missions in microgravity lead to health issues such as bone loss.

Hawking favors human space exploration, rather than just sending robots to explore space, a position taken by Nobel laureate Steven Weinberg, among others.

Eventually, Hawking said, humanity should try to expand to Earth-like planets around other stars. If only 1% of the 1000 or so stars within 30 light years of Earth has an Earth-size planet at the right distance from its star for liquid water to exist, that would make for 10 such planets in our solar system’s neighbourhood, he said.

“We cannot envision visiting them with current technology, but we should make interstellar travel a long-term aim,” he said. “By long term, I mean over the next 200 to 500 years.” Humanity can afford to battle earthly problems like climate change and still have plenty of resources left over for colonizing space, he said.

“Even if we were to increase the international [space exploration] budget 20 times to make a serious effort to go into space, it would only be a small fraction of world GDP,” he said. GDP, or Gross Domestic Product, is a measure of a country’s economic activity.

Hawking  believes that traveling into space is the only way humans will be able to survive in the long-term. “Life on Earth,” Hawking has said, “is at the ever-increasing risk of being wiped out by a disaster such as sudden global warming, nuclear war, a genetically engineered virus or other dangers … I think the human race has no future if it doesn’t go into space.”

Another of his famous quotes reiterates his position that we need to get off the planet relatively soon. “I don’t think the human race will survive the next 1,000 years unless we spread into space.”

The problems with Hawking’s solution is that while it may save a “seed” of human life- a few lucky specimens- it won’t save Earth’s inhabitants. The majority of Earthlings would surely be left behind on a planet increasingly unfit for life.

Hawking argued that the world can afford 0.25% of its collective GDP to devote to space colonization. “Isn’t our future worth a quarter of a percent?” he asked. The physicist also speculated on the reasons that SETI (Search for Extra-Terrestrial Intelligence) projects have not yet detected any alien civilizations, offering three possibilities: that life of any kind is very rare in the universe; that simple life forms are common, but intelligent life rare; or that intelligent life tends to quickly destroy itself.

“Personally, I favour the second possibility – that primitive life is relatively common, but that intelligent life is very rare,” he said. “Some would say it has yet to occur on Earth.”

Source: DailyGalaxy

“The Great Silence” -Stephen Hawking & Others Look At Why Life Has Yet to be Discovered Beyond Earth

In astronomy, sci-fi on February 28, 2010 at 10:23 am

“The idea that we are the only intelligent creatures in a cosmos of a hundred billion galaxies is so preposterous that there are very few astronomers today who would take it seriously. It is safest to assume therefore, that they are out there and to consider the manner in which this may impinge upon human society.”

Arthur C. Clarke, physicist and author of 2001: A Space Odyssey

One of the greatest philosophical and scientific challenges that currently confronts humanity is the unsolved question of the existence of extraterrestrial intelligence.

The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for or contact with such civilizations.

The 14-billion-year age of the universe and its 130 billion galaxies and a Milky Way Galaxy with some 400 billion stars suggest that if the Earth is typical, should be common. Nobel laureate Enrico Fermi, discussing this observation with colleagues over lunch in 1950, asked, logically: “Where are they?” Why, if advanced extraterrestrial civilizations exist in our Milky Way galaxy, hasn’t evidence such as probes, spacecraft, or radio transmissions been found?

As our technologies become ever more sophisticated and the search for extraterrestrial intelligence continues to fail, the “Great Silence” becomes louder than ever. The seemingly empty cosmos is screaming out to us that something is amiss. Or is it?

Using a computer simulation of our own galaxy, the Milky Way, Rasmus Bjork, a physicist at the Niels Bohr Institute in Copenhagen, proposed an answer to the Fermi Paradox. Bjork proposed that an alien civilization might build intergalactic probes and launch them on missions to search for life.

He found, however, that even if the alien ships could hurtle through space at a tenth of the speed of light, or 30,000km a second, – NASA’s current Cassini mission to Saturn is gliding along at 32km a second – it would take 10 billion years, roughly half the age of the universe, to explore a mere four percent of the galaxy.

Like humans, alien civilizations could shorten the time to find extra-terrestrials by picking up television and radio broadcasts that might leak from colonized planets. “Even then,” he reported, “unless they can develop an exotic form of transport that gets them across the galaxy in two weeks it’s still going to take millions of years to find us. There are so many stars in the galaxy that probably life could exist elsewhere, but will we ever get in contact with them? Not in our lifetime.”

The problem of distance is compounded by the fact that timescales that provide a “window of opportunity” for detection or contact might be quite small. Advanced civilizations may periodically arise and fall throughout our galaxy as they do here, on Earth, but this may be such a rare event, relatively speaking, that the odds of two or more such civilizations existing at the same time are low.

In short, there may have been intelligent civilizations in the galaxy before the emergence of intelligence on Earth, and there may be intelligent civilizations after its extinction, but it is possible that human beings are the only intelligent civilization in existence “now.” “Now” assumes that an extraterrestrial intelligence is not able to travel to our vicinity at faster-than-light speeds, in order to detect an intelligence 1,000 light-years distant, that intelligence will need to have been active 1,000 years ago.

There is also a possibility that archaeological evidence of past civilizations may be detected through deep space observations — especially if they left behind large artifacts such as Dyson spheres.

Perhaps…but in our search for life and intelligence we have to keep in mind that the Milky Way Galaxy is two or three times the age of our Solar System, so there are going to be some societies out there that are millions of years, maybe more, beyond ours, which may have proceeded beyond biology—that have invented intelligent, self-replicating machines and it could be that what we first find is something that’s artificially constructed if we have the ability to recognize it as such. It may very well be that our greatest discovery will be that the very nature of alien communication will prevent our being able to communicate with it.

In his famous lecture on Life in the Universe, Stephen Hawking asks: “What are the chances that we will encounter some alien form of life, as we explore the galaxy?”

If the argument about the time scale for the appearance of life on Earth is correct, Hawking says “there ought to be many other stars, whose planets have life on them. Some of these stellar systems could have formed 5 billion years before the Earth. So why is the galaxy not crawling with self-designing mechanical or biological life forms?”

Why hasn’t the Earth been visited, and even colonized? Hawking asks. “I discount suggestions that UFO’s contain beings from outer space. I think any visits by aliens, would be much more obvious, and probably also, much more unpleasant.”

Hawking continues: “What is the explanation of why we have not been visited? One possibility is that the argument, about the appearance of life on Earth, is wrong. Maybe the probability of life spontaneously appearing is so low, that Earth is the only planet in the galaxy, or in the observable universe, in which it happened. Another possibility is that there was a reasonable probability of forming self reproducing systems, like cells, but that most of these forms of life did not evolve intelligence.”

We are used to thinking of intelligent life, as an inevitable consequence of evolution, Hawking emphasized, but it is more likely that evolution is a random process, with intelligence as only one of a large number of possible outcomes.

Intelligence, Hawking believes contrary to our human-centric existece, may not have any long-term survival value. In comparison the microbial world, will live on, even if all other life on Earth is wiped out by our actions. Hawking’s main insight is that intelligence was an unlikely development for life on Earth, from the chronology of evolution: “It took a very long time, two and a half billion years, to go from single cells to multi-cell beings, which are a necessary precursor to intelligence. This is a good fraction of the total time available, before the Sun blows up. So it would be consistent with the hypothesis, that the probability for life to develop intelligence, is low. In this case, we might expect to find many other life forms in the galaxy, but we are unlikely to find intelligent life.”

Another possibility is that there is a reasonable probability for life to form, and to evolve to intelligent beings, but at some point in their technological development “the system becomes unstable, and the intelligent life destroys itself. This would be a very pessimistic conclusion. I very much hope it isn’t true.”

Hawkling prefers another possibility: that there are other forms of intelligent life out there, but that we have been overlooked. If we should pick up signals from alien civilizations, Hawking warns,”we should have be wary of answering back, until we have evolved” a bit further. Meeting a more advanced civilization, at our present stage,’ Hawking says “might be a bit like the original inhabitants of America meeting Columbus. I don’t think they were better off for it.”