Skytalk

The dim red star Proxima Centauri, 4.2 lightyears from Earth, is known to have an EarthPlus-planet in the star’s habitable zone. Now a second planet has been detected, but this one is 5.8 times the mass of our planet and orbits its star only once every five years. Unfortunately, it’s also too far from the cool star to be warm enough for liquid water. So, it’s not habitable – at least for us. Which leads to a proposal to send 1,000 tiny spacecraft – really just a computer chip attached to a solar sail driven by ground-based lasers with 100 gigawatts of power to drive them along. The idea is that the tiny chips, with so little mass, could be driven up to 15-20% of the speed of light, making the 4.2 light year trip in just 20-30 years. Initial funding of $100 million comes from Russian Yuri Milner, backed by Mark Zuckerberg and Stephen Hawking. –When totaling up all the matter in the universe, cosmologists believe that about 80% of the mass of the universe is completely unseen dark matter, 21% is dar