From here to Alpha Centauri

If you’d like some bragging rights to your friends in Tokyo, Seoul, or Shanghai, here’s a name to lay on them: Alpha Centauri. It’s a star that you can see from Saipan, but it can’t be seen from the higher northern latitudes, including the cities I just mentioned.

Alpha Centauri was one of the big astronomy stories of 2016. Today we’ll catch up with that story by doing some armchair space-travel. So drop an ice cube in your drink, fire up a fresh smoke, and let’s get going.

Alpha Centauri is the third-brightest star in the night sky. In Saipan it’s visible over the southern horizon just before dawn. You really have to go to the southern hemisphere for Alpha Centauri to have some decent altitude. In any case, though, to the bare eyeball Alpha Centauri looks like a single point of light.

It’s really a system of three stars, though. The term Alpha Centauri is often used as a blanket word to cover the entire trio.

Two of the stars are pretty much like our sun, and are locked into orbit with each other because of their mutual gravitation. But it’s the third star that’s in the news right now. This star is called Proxima Centauri. If the term “Proxima” seems a lot like “proximate,” you’re right: Proxima Centauri is the closest star to our own sun. In cosmic terms, it’s right next door at 4.2 light-years.

In stellar terms, it’s a dim pipsqueak known as a red dwarf. It’s only a little bit bigger than the planet Jupiter. It turns out that many, perhaps most, of the stars in our galaxy are red dwarfs. People who search for extra-terrestrial life, then, must contemplate whether or not red dwarfs can support planets that might be able to support life. If red dwarfs could deliver on that note, it would be a big deal.

And just such a big deal was unveiled in August. That’s when it was announced that Proxima Centauri appears to have a planet. The planet may be a rocky planet (Earth is also a rocky planet, as opposed to a gaseous planet) and its orbital distance may put it in the “habitable zone” where water can exist in a liquid state. This planet is called “Proxima b.”

Promixa b has not been directly observed. Its existence was surmised by observing the behavior of Proxima Centauri, which is influenced by the tug of the planet’s gravity. So there’s a lot of scientific conjecture here, as opposed to rock-solid proof.

Still, for hunters of extra-terrestrial life, finding that our very nearest stellar neighbor harbors a candidate for habitability has kicked off a lot of excitement.

Unfortunately, even though 4.2 light-years is a puny distance on the cosmic scale, our earthling technology is far too feeble to tackle it. Assuming the space shuttle could go that far, it would take, according to the EarthSky website (EarthSky.org), 165,000 years to make the trip. I’ve been around aviation long enough to know that there’s no way that any chief pilot would approve that much per diem pay for the flight crew. So a trip like this just isn’t realistic.

But there is a research project in the works that hopes to get some ultra-small space probes (each probe the size of a sugar cube) zooming to Alpha Centauri at a speed of 20 percent of the speed of light. The trip would take about 20 years, and then it would take 4.2 years for any radio signals (such as a photo of Proxima b) to get back to Earth. The big idea is to use super-duper powerful lasers on Earth to push a “light sail” that propels the little space probes. The name of the project is “Breakthrough Starshot.” If you run a Web search for the term you’ll see lots of information.

Even in the best case scenario, with all the time it would take to get something like this working I’ll probably be long gone before any photos of Proxima b ever reach Earth. Actuaries, alas, can’t be denied any more than chief pilots can. But some of you younger Saipan Tribune readers could conceivably live to see the day when news from Proxima b reaches Earth. In that case, I hope you’ll raise a toast to the memory of your star-struck newspaper columnist.

In fact, a toast seems like a pretty good idea right about now; after all, we’ve safely returned from our armchair space mission. Alpha Centauri isn’t Saipan’s most famous sight, but it’s proving to be a doorway to astronomical adventure.