Our Stellar Neighbor Beckons

Listen 09:04
A shot of Proxima Centauri from the Hubble Telescope. Image: ESA/Hubble & NASA

A shot of Proxima Centauri from the Hubble Telescope. Image: ESA/Hubble & NASA

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 dark energy and just 4% is all the actual matter of the universe. According to all the mass of the universe that can be accounted for, the universe’s rate of expansion, left over after the universe’s inflation period, should indicate a gradual decrease in that expansion rate – the expansion should be slowing. But it isn’t. In fact, it’s accelerating!
To compensate, cosmologists have introduced the concept of dark energy – an unseen and undetectable force that seems to be pushing clusters of galaxies apart. If the expansion push is totaled up across the universe, the result accounts for the rate of expansion now seen in the universe. Now the basic premise behind dark energy, the unseen force that seems to be driving the universe’s increasing expansion rate, has a serious flaw related to how distance around the universe is determined.
If that discrepancy cannot be resolved, it may be that dark energy isn’t a piece of the cosmic puzzle at all.
The new observations haven’t been widely accepted and the results have to be tested by other research teams. Stay tuned.

The Moon and Mars are visible early this week in the 6:15 – 6:30 a.m. window in the East. Jupiter is now very low in the east at 6:30 a.m. Yes, that’s Venus in the south-west after sunset. It’ll be there for a few months, getting brighter and higher.

Want a digest of WHYY’s programs, events & stories? Sign up for our weekly newsletter.

Together we can reach 100% of WHYY’s fiscal year goal