Alpha Centauri, here we come.

Stephen Hawking wants to send tiny space probes to the stars
'Nanocraft' would explore Alpha Centauri

UPDATED 4:46 AM PDT Apr 13, 2016


Text Size:AAAStephen Hawking, blurb photo
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(CNN) —Imagine hundreds of spacecraft the size of a butterfly, propelled by light beams at record-shattering speeds and journeying to distant stars 4.37 light years away -- far deeper into space than human-built probes have ever ventured.

It's arguably the most ambitious space exploration project in history, and it may not be completed in our lifetimes.

But if anyone can pull it off, it's these guys.

Some of the world's most brilliant minds, including physicist Stephen Hawking and Facebook founder Mark Zuckerberg, are behind a $100 million program to send tiny "nanocraft" to explore Alpha Centauri, our nearest star system.

"Today, we commit to this next great leap into the cosmos," Hawking said alongside billionaire entrepreneur Yuri Milner at a press conference Tuesday in New York. "Because we are human, and our nature is to fly."

Hawking, Milner and Zuckerberg make up the board of directors for the mission, which is called Breakthrough Starshot and seeks to apply Silicon Valley ingenuity to space travel. The project is led by Pete Worden, former director of NASA's Ames Research Center, and advised by a committee of top scientists and engineers.

Their plan goes like this: They hope to build hundreds of little space probes, each weighing just a few grams and carrying cameras, photon thrusters, power supply, navigation and communication equipment. A rocket would ferry these nanocraft into space, where they would unfold tiny sails.

Powerful laser beams from Earth would then push the sails, propelling the little nanocraft up to 100 million mph -- that's 20% of light speed, far faster than today's spacecraft can travel -- to Alpha Centauri, where they would collect images and other data and beam them back to Earth.

Project leaders estimate that today's fastest spacecraft would take about 30,000 years to reach the Alpha Centauri star system, some 25 trillion miles away. But they believe these nanocraft could fly more than 1,000 times faster, which would allow them to reach Alpha Centauri in about 20 years.

The project's leaders admit they face big engineering challenges, and that any launch is many years and billions of dollars away. But they say their plans are based on technology that already exists or is likely to become available soon.

They also plan to ask the world's scientists for their help by posting public-domain research and soliciting ideas online.

Some scientists are skeptical they can make this happen, given the current limits of technology and the difficulty of raising enough money to fund the project. The Russian-born Milner estimates it could cost as much as $10 billion.

But he and his colleagues for now are optimistic.

"The human story is one of great leaps," Milner said in a statement. "Fifty-five years ago today, (Russian cosmonaut) Yuri Gagarin became the first human in space. Today, we are preparing for the next great leap -- to the stars." by Brandon Griggs

"The question of whether advanced civilizations exist elsewhere in the universe has always been vexed with three large uncertainties in the Drake equation," said Adam Frank, professor of physics and astronomy at the University of Rochester and co-author of the paper. "We've known for a long time approximately how many stars exist. We didn't know how many of those stars had planets that could potentially harbor life, how often life might evolve and lead to intelligent beings, and how long any civilizations might last before becoming extinct."

The result? By applying the new exoplanet data to the Universe as a whole, Frank and Sullivan find that human civilization is likely to be unique in the cosmos only if the odds of a civilization developing on a habitable planet are less than about one in 10 billion trillion, or one part in 10 to the 22th power.

"One in 10 billion trillion is incredibly small," says Frank "To me, this implies that other intelligent, technology producing species very likely have evolved before us. Think of it this way. Before our result you'd be considered a pessimist if you imagined the probability of evolving a civilization on a habitable planet were, say, one in a trillion. But even that guess, one chance in a trillion, implies that what has happened here on Earth with humanity has in fact happened about a 10 billion other times over cosmic history!"

For smaller volumes the numbers are less extreme. For example, another technological species likely has evolved on a habitable planet in our own Milky Way galaxy if the odds against it evolving on any one habitable planet are better than one chance in 60 billion.

But if those numbers seem to give ammunition to the "optimists" about the existence of alien civilizations, Sullivan points out that the full Drake equation -- which calculates the odds that other civilizations are around today -- may give solace to the pessimists.

"The universe is more than 13 billion years old," said Sullivan. "That means that even if there have been a thousand civilizations in our own galaxy, if they live only as long as we have been around -- roughly ten thousand years -- then all of them are likely already extinct. And others won't evolve until we are long gone. For us to have much chance of success in finding another "contemporary" active technological civilization, on average they must last much longer than our present lifetime."