Across the Universe: Return to Dust
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This column first ran in The Tablet in October 2013 For about six months, our Moon had a moon of its own: a small artificial satellite called “Ladee”, the Lunar Atmosphere and Dust Environment Explorer. Costing just under $300 million, a bargain, it is a little bit smaller than a Smart Car, a little bit larger than a Tardis: 7.7 feet tall, with a hexagonal cross section 4.7 feet in diameter. NASA launched it with an assembly of rockets built from old “Peacemaker” ICBM missiles. Originally designed to send nuclear bombs to the Soviet Union, these rockets are strictly controlled under a US-Russian arms treaty: the small facility at Wallops Island, off the Virginia coast, is one of the few places allowed to launch them. Thus, a bit before midnight on September 6, 2013, the rockets’ red glare was visible from nearby Washington DC and the eyes of the Congress who’d paid for it. These small rockets put the spacecraft … Continue reading

Across the Universe: Feeding Curiosity
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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. Granted, 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 … Continue reading

Across the Universe: Clouds of witnesses
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This column first ran in The Tablet in September, 2016 Scientists communicate with images. We want to know not simply one value, but how each value compares with other values measured in other situations: other times, other samples, other planets. Picturing our data as spots on a grid is worth a thousand numbers. At the 2016 meeting of the Meteoritical Society in Berlin, every paper relied on images with specks of many colors (each color also a different shape, for the the color-blind) representing different sets of data. No number is perfect; no single measurement is perfect. We repeat each measurement tens, hundreds, thousands of times. If you were to plot each measurement you’d get a cloud of dots and hope that the truth is somewhere within that cloud. The better your precision, the tighter your cloud, the better you can guess where the truth may lie. Instead of plotting all the thousands of individual measurements, though, it’s usually sufficient to … Continue reading

Across the Universe: Reaching out
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This column first ran in The Tablet in September 2015 Eighty years ago, on September 29, 1935, Pope Pius XI dedicated new quarters and telescopes of the Vatican Observatory in his summer palace in Castel Gandolfo. To celebrate the anniversary,in September 2015 we held a symposium in Castel Gandolfo, including a visit to the old domes that Pius XI had dedicated. The party ended in a private audience in Rome with Pope Francis (less than 24 hours before he left for Cuba and the US). After giving us a short address, the Pope looked up and caught my eye. He smiled, and said, “Ah! The New Director!” It’s true. As of that day, I became the new director of the Vatican Observatory. (I actually didn’t completely believe it until I heard him say it.) Would I continue to write articles like these (for the Tablet)? Yes, as long as there’s a place for me. It’s not only because I love being … Continue reading

Across the Universe: The Church of UFO
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This column first ran in The Tablet in September 2014 “Preparing for Discovery,” a two day symposium at the US Library of Congress to discuss the possible impact on society of finding life in space, was my destination [September 2014]. Discovering life outside Earth would be a major advance in understanding biology; finding intelligent life would colour how we understand being human. But it’s a magnet for our hopes and fears. The field of astrobiology still has a hard time escaping the taint of “little green men.” Thus nearly all the speakers went out of their way to emphasize that they were Serious Scientists, viewing life and intelligence from a purely secular and, indeed, materialistic viewpoint. Constant reference was made to the “N=1” problem: how can you define life, much less intelligence, when the number of planets known to harbour life only equals one? Still, the laws of physics do provide some guideposts. And understanding the origin of that one … Continue reading

Across the Universe: Leaving the neighborhood
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This column first ran in The Tablet in September 2013 At the annual European Planetary Science Congress [held in September 2013] in London, I was chatting with some postgraduate students about their studies of Jupiter’s icy moon, Europa. It’s the target of the Jupiter Icy Moon Explorer mission that the European Space Agency hopes to launch in 2022. Europa’s subcrustal oceans may be the best place in our solar system to look for non-terrestrial life forms – an idea that I can claim credit for first proposing in print in 1975, based not so much on my computer models as on all the science fiction I’d been reading.           It’s exciting to see a crazy idea of mine (and, to be honest, of many other folk) turned into a space mission. But it’s sobering to realize I will be 78 years old in 2030, when it arrives. Indeed, not only were those postgraduate students not yet … Continue reading

Across the Universe: Myriad planets
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This column first ran in The Tablet in September 2012 One hundred thousand planets. That’s the census we can infer for just one corner of the Milky Way Galaxy being watched by the Kepler space telescope, according to results presented [August 2012] at the International Astronomical Union in Beijing. Watching each of 145,000 stars in a bit of the Milky Way about 10 degrees wide over many years (three and a half years, [as of that time]), Kepler is looking for faint dips in brightness occurring on a regular basis that can be attributed to the passage, a “transit”, of a planet in front of that star. So far some 2300 candidate planets have been identified. (Many stars have more than one candidate.) But in order for us to see such a blip, the planet’s orbit must be lined up almost exactly between the star and us; we’re missing any planets whose orbits are tilted above or below their star … Continue reading

Across the Universe: Super Earths
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This column first ran in The Tablet in August 2015 Half the planets in our solar system are relatively small, rocky, and found near our sun. The other half are all significantly bigger, covered in giant atmospheres, and orbit far away from the sun. Explaining this trend in size and orbits is simple. If the planets formed from a disk of gas and dust (we’ve actually observed such disks around young stars) then planets forming farther from the sun are colder. If they’re far enough from the sun that water in the gas freezes into ice, they’ll jump up in size — a gas cloud has twice as much water as rocky material to snowball into a planet. And once a planet reaches a critical size, it captures gas from the nebula to make a thick atmosphere. So, inner rocky planets stay small; but once the icy outer planets get big enough, they jump up to even larger sizes. The … Continue reading

Across the Universe: Ice dreams
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This is a slightly edited version of a column that first ran in The Tablet in August 2014 ESA’s Rosetta spacecraft arrived at comet 67P/Churyumov–Gerasimenko on August 6, 2014. Launched more than ten years earlier, upon arrival it took up an orbit around the sun that parallels the comet’s path, to keep the comet in its cameras from a distance of only a few tens of kilometers. The next two months saw intense preparation for the final stage of the mission: in mid November, 2014, a lander was sent to the comet’s dark surface with instruments to measure its composition in close up detail. (The original plan was for it to drill about 20 cm into the comet itself, to pierce the dusty crust and reach the icy material beneath. Alas, it landed into a shadowed region and was not able to get enough power to do its job or communicate with the orbiter… its fate is described here, on … Continue reading

Across the Universe: Shrine to the stars
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The column first ran in The Tablet in August 2013 The Milky Way arched over my head, a swath of light through an inky-black sky streaking from Cassiopeia on the northern horizon, through the cross of Cygnus, to the hook of Scorpius just above the horizon due south. I was on a hilltop in southern Vermont attending this year’s annual convention of amateur telescope makers known as Stellafane. The name, we were told, means “shrine to the stars.” It’s not only the dark skies that attract amateurs to this location. Ninety years ago a group of twenty precision toolmakers in the small mill town of Springfield, Vermont, first gathered to share their knowledge of mirror-making and show off their equipment. In 1923, if you wanted a small telescope to look at the stars you either paid a small fortune or you made it yourself. Grinding a mirror into the parabolic shape that can focus faint starlight into a bright point … Continue reading

Across the Universe: Pennies from heaven
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A slightly shorter version of this column first ran in The Tablet in August 2012 Scientists who do experiments need material to experiment on. Thirty years ago, a grad student friend of mine ran into a problem researching motor skill development in infants because there were too many other students in her field writing theses, and not nearly enough infants available in her university town with parents willing to have them studied. (Ironically, my friend was herself pregnant at the time. Her baby, now grown, defended her own psychology dissertation in the fall of 2012; she’s now a psychology professor herself. And a mom, as well.) In meteoritics we cannot advertise for samples, much less produce them ourselves. We have to wait for our subject matter to fall, like manna, from the heavens. In 2012, however, we were fortunate to have two fascinating new meteorites land at our feet. They were each the subject of special sessions at the annual … Continue reading

Across the Universe: Planetary Prejudice
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This column first ran in The Tablet in July 2015 The wonderful excitement about Pluto, visited by the New Horizons spacecraft [July 2015], has resurrected the old issue of defining a “planet”. But why? Most people approaching this question have one clear goal: they want Pluto to be a planet. Once you realize that, you can make your definition clear and simple: “A planet is one of the bodies that I was taught was a planet when I was a child.” Of course, such a definition is useless for any other purposes. The IAU, which defined Pluto and similar bodies as “dwarf planets” back in 2006, needed a definition so it could name such objects and the features on them, to know whose committee and what set of rules will apply. But there’s another aspect to this issue. Fifteen years ago I was involved in a research program studying the Trans-Neptunian Objects (TNO) that orbit alongside Pluto, comparing their shapes … Continue reading