New Planets and How to Get There

There were several major announcements in the field of astronomy this month, but two stood out in particular. 

On February 22, NASA announced the discovery of seven Earth-sized planets orbiting a star known as TRAPPIST-1,  located at a relatively close 40 light years away. Exoplanets are discovered fairly often these days, but three of these planets are orbiting in the elusive habitable zone, setting the record for the number of potentially habitable planets in one system.

Now, obviously “in the habitable zone” doesn’t mean that a planet has life, or even that it’s necessarily habitable at all. Just that it has the potential for this. Mars is technically in the habitable zone of our solar system, but unless it undergoes some pretty drastic changes you’ll never be able to walk on it without a spacesuit.

As I’ve explained in another blog, finding a planet in a star’s habitable zone just fulfills one more factor in the Drake Equation.

But even if these planets were habitable oases, filled with lush forests and fresh water, 40 light years is impossibly far away right now. It took the New Horizon’s spacecraft 9.5 years to reach Pluto, traveling at a constant velocity of 27,000 miles per hour. Even assuming that a human could travel at space shuttle speeds for unlimited amounts of time without stopping, the trip would take 25 years. And Pluto is only 7.4 light hours away from the Earth at the furthest point in its orbit.

This is where we come to the second astronomy headline: some scientists have proposed a plan to put a probe around one of the planets of our nearest cosmic neighbor, Proxima Centauri, a relatively close 4.24 light years away.

Last year, Stephen Hawking had proposed a similar plan, but it had one major “flaw.” In order to reach the star within a reasonable time frame (20 years), a probe would be have to be traveling so quickly that it wouldn’t be in the star system longer than a few minutes.  But a new plan, proposed by astrophysicists Michael Hippke and René Heller, could slow a probe down long enough to put it in orbit around one of the three stars in that system.  Unfortunately, slowing the probe down enough to get it in orbit will tack on so much time to the trip that nobody working on it will be able to see it through. With the new plan, it would take 95 years for the probe to reach the first star, and 46 more to reach its final destination — not to mention that the technology to propel the probe that far still needs to be developed. 

 You can read more about this plan here: 

And you can watch a video by NASA’s Jet Propulsion Laboratory on the TRAPPIST-1 discovery here: