This column first ran in The Tablet in October 2012
Finally [in 2012!], a planet has been discovered orbiting Alpha Centauri. That star, a neighbor of the Southern Cross, is actually a triplet of stars orbiting each other – as first discovered by a Jesuit missionary, Fr. Jean Richaud, some 300 years ago. And it’s is our nearest neighbor, merely four and a half light years away.
NASA’s Juno spacecraft was racing away from Jupiter following its seventh close pass of the planet when JunoCam snapped this image on May 19, 2017, from about 29,100 miles (46,900 kilometers) above the cloud tops. The spacecraft was over 65.9 degrees south latitude, with a lovely view of the south polar region of the planet. This image was processed to enhance color differences, showing the amazing variety in Jupiter’s stormy atmosphere. The result is a surreal world of vibrant color, clarity and contrast. Four of the white oval storms known as the “String of Pearls” are visible near the top of the image. Interestingly, one orange-colored storm can be seen at the belt-zone boundary, while other storms are more of a cream color. JunoCam’s raw images are available for the public to peruse and process into image products at: www.missionjuno.swri.edu/junocamGranted, the new planet orbits so close to its star (the middle member of the triplet) that its surface would be hotter than molten lava. But its existence gives hope that Alpha Centauri could also host another planet at a more temperate location, which we just haven’t seen yet. Unlike other detected planetary systems, you could actually envision a conversation with hypothetical intelligences inhabiting such a hypothetical planet; the conversation lag would be a mere nine years between exchanges.
Could we go there? Half a century ago, it took Apollo about a week to get to the Moon and back. Getting people to Mars (round trip, two years with present technology) is technically doable but so challenging and expensive that we’ve only sent robots on one-way trips so far. But Alpha Centauri is a bit further away. A chart that placed our Moon one centimeter from Earth would need to be a thousand kilometers wide before you could map Alpha Centauri’s position. At the rate Apollo went to the Moon, it would take a million years to get there.
The same week that this announcement was made in Switzerland, I was with six hundred planetary astronomers in Nevada at the annual meeting of the American Astronomical Society’s Division for Planetary Sciences. The reaction there to Alpha Centauri’s planet was, “cool!” – followed immediately by each of us returning to all the talks and posters and collaborations-in-the-hallways that make up a typical scientific meeting. Science is not only done in major discoveries; it is also many tiny bits of work, innumerable puzzle pieces, accumulated by a small, dedicated, slightly crazy clan of scruffy astronomers.
We heard a new twist on the standard theory for the origin of the Moon, immediately challenged by a fellow modeler… who later told me, “that was the best paper of the meeting, even though I don’t agree with her results.” We heard plans to image the poles of Jupiter with a camera on a Nasa mission due to arrive in four years. That’s the Juno mission, whose results and incredible polar images can now be seen here.] For the first time, a planet’s been found orbiting a star that’s part of a quadruple system.
These last two items had a special twist. The quadruple star’s planet was found by amateurs using the “Planet Hunters” citizen science website (planethunters.org). And, likewise, on-line amateurs will make the target selection decisions for the Jupiter camera and reduce the resulting images, cleaning up the computer glitches and balancing the colors. Those amateurs are already providing images of Jupiter with backyard telescopes that rival what once only the best professional telescopes could provide.
Amateurs’ telescopes are often the fruits of their lucrative high tech careers; we professionals spend our lives grubbing for the grants that pay for our Curiosities. But amateurs don’t get paid to dedicate all their thinking hours to the latest discoveries in the field. Nor do they get to gossip over coffee with friends who’ve known each other since student days, mixing new data on Mercury with news on who’s just become a grandfather.
The discovery of a planet around a nearby star can inspire the imagination of the amateurs (and taxpayers), our biggest fans and supporters. But we professionals are consumed by the minutia of daily data. Only with such work can we help the amateurs make sense of what they’ve seen, like a spiritual director guiding someone through a numinous experience.
And in return, their enthusiasm reminds us of why we do the work.
