Dusted by stars
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I have had Jon Larsen’s  In Search of Stardust on my stack of books to read because last spring the upper division research methods course I taught did an experiment to measure the heat capacities of meteorites, using the method developed by the Vatican Observatory’s Guy Consolmagno, SJ and Bob Macke, SJ and colleagues. The students were curious about the astrochemistry context (where do the samples come from, how can you distinguish regular rocks from these stony aliens) and I’ve been collecting resources for this coming spring when a new batch of students will make these measurements. I tend to think of meteor strikes as spectacular and rare events, fireballs roaring through the sky that finally come crashing to earth.  Still they aren’t as rare was you might think — tens of thousands of meteorites weighing as much or more than a euro coin hit the earth’s surface each year, most of them landing in the water.  It gives me a visceral … 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: Hidden inclusions
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This column first ran in The Tablet in July 2013 I was in a state of high excitement (or what passes for such when you’re sixty years old): the Pope was coming to lunch with our Jesuit community at the Vatican Observatory! Meanwhile, I was also preparing a paper for the annual Meteoritical Society meeting, and I had just noticed a wonderful correlation in my data. These sorts of insights are as rare as Papal visits… if indeed I had really made one. I’ve been studying iron meteorites; and it’s been hard work. For one thing, they are, quite literally, hard – lumps of nickel-iron, too hard to cut up easily to see what’s inside. I’ve seen iron meteorites being cut at the Smithsonian in Washington, DC; their saw sits in a room the size of gymnasium, makes an awful racket, and spews water everywhere. (The water cools the meteorite while a diamond-encrusted wire scrapes through it.) When you do … Continue reading

Across the Universe: Touched by Heaven
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This column first ran in The Tablet in January 2014 On February, 15, 2013 [one year before this column first ran], a twenty-meter chunk of space rock hit the Earth over Chelyabinsk, Siberia. Shining brighter than the sun, its fall was recorded by video cameras as far as 700 km away. Thousands of people in Chelyabinsk ran to their windows to see what that bright light was; a few moments later, the impact’s sonic boom arrived and shattered those windows. More than 1500 people were hurt by flying glass and debris. Seventy kilometers west of Chelyabinsk, an eight meter wide hole was found in the ice of Lake Chebarkul; last summer, a half-ton meteorite was recovered from the lake bottom. It’s not every day that a rock with half a megaton of energy hits the Earth above a major city (a million people live in Chelyabinsk). But near earth asteroids are hardly rare. The Minor Planet Center in Cambridge, Massachusetts, keeps … Continue reading

Across the Universe: Heavenly Visitors
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This column first ran in The Tablet in December 2006 The reporter from the BBC was shocked that I wasn’t shocked: Could the seeds of life have come to Earth from outer space? He was interviewing me about a new [in 2006] discovery published in Science. In a meteorite retrieved from a frozen lake in northern Canada, researchers found chemical compounds that could be the precursors of life, sitting in small round voids that could have served as the templates for early cells. Meteorites are my business, and the scientists cited are colleagues and friends of mine, but even so I couldn’t understand why a BBC reporter in London was trying to interview me. The data are new and intriguing, yes, but it’s hardly a new idea. For more than 150 years, meteorites have been known to contain organic chemicals. “But doesn’t the stuff of life coming to us from off the Earth contradict the Church’s teaching that only Earth is … Continue reading

Across the Universe: Featureless Features
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At the end of September 2016, Rosetta finally ended its mission by crashing into its comet. This column, about an earlier aspect of the Rosetta mission, first appeared in The Tablet in October 2010   Back in July [2010], ESA’s Rosetta spacecraft, en route to a comet rendezvous in 2014, flew past asteroid Lutetia, a 100 km pile of rock orbiting between Mars and Jupiter. The result of that encounter was a hot topic of both the European Planetary Science Conference in Rome in September and a meeting of American planetary astronomers in Pasadena in October [2010]. Studying asteroids has always been challenging. Even in the largest telescopes they’re mere dots of light, too small to show any shapes, much less surface details. We can only infer their nature from the most subtle of hints: how their brightness varies as they spin, how much infrared light they radiate, their visible and infrared colours. Minerals that contain iron oxide or water reveal themselves by … Continue reading

Across the Universe: Dawn of My Belief
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This column first ran in The Tablet in June 2011 As a graduate student in 1976 I gave a paper to the Meteoritical Society about a theory that I (and my thesis advisor) had developed concerning a rare class of meteorites which appeared to be bits of lava from the surface of an asteroid. While most asteroids are collections of metal and rock, we knew that some of them must have melted; for one, asteroid Vesta’s infrared colors exactly matched the spectra of these basaltic meteorites. Our work determined that for every gram of lava in these meteorites, there should have been another nine grams of residue in its parent asteroid. After my talk, a grand old man of the field approached me. “If these meteorites come from an melted asteroid,” he asked, “lavas flowing to the top and residue in the center, then once it was broken into meteorites, shouldn’t we have we seen nine times as many meteorites from … Continue reading

Across the Universe: Grain of truth
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This column first ran in The Tablet in June, 2010. Travel, a favorite summer pastime, carries with it certain social perils. After I came back from my Peace Corps service, it was astonishing how often I would find myself uttering “when I was in Africa…” as every conversation would seem to trigger some memory I just had to share. Ten years later I added “when I was in Antarctica” to my repertoire. Thank God for patient friends. I recall telling a colleague about a star-gazing trip I was planning to Australia in August. He lamented that his only trip there was cloudy the entire week, so he didn’t get a chance to see any of the southern stars. “The only time I remember ever getting to see the Southern Cross was out Shuttle’s porthole…” One-upped by an astronaut! (Thanks, Tom Jones.) But even my astronaut friend has not had a voyage like the space probe Hayabusa. Launched by the Japanese Space Agency in … Continue reading

Across the Universe: Treasure from Heaven
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This column first ran in The Tablet in May, 2009 Above the Arizona sky the night of October 5, 2008, a faint moving dot of light was captured in the Skywatch telescope. Soon its orbit was calculated, showing that this newly discovered asteroid, 2008 TC3, had only 20 hours left before it was to hit the Earth. Two dozen teams of astronomers made every possible use of that time, measuring its colors and changing brightness as it spun across the sky, and further refining its orbital path. On the morning of October 7 (local time), a tumbling lump the size of a white van struck the sky over northern Sudan. Seven months later, in a quiet conference room in Prague, Peter Jenniskens told a rapt audience of bolide and meteorite specialists (I was one) the story of what happened next. Through e-mails to friends and colleagues, this Dutch-American meteor specialist had made contact with a geologist at the University of … Continue reading

Across the Universe: Touch the Sky
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This column first ran in The Tablet in April, 2010 Next summer [2011], the “Dawn” spacecraft will go into orbit around Ceres and Vesta, biggest and brightest of the asteroids. (Indeed they are so much larger than the other asteroids that they may be better classified as dwarf planets.) These bodies have been well studied by telescope for more than 200 years – Ceres was discovered on New Year’s Day, 1801, by the Sicilian priest-astronomer Giuseppe Piazzi – but seeing them remotely is nothing like getting a close-up view. [In April of 2010], a team of scientists and engineers met in Rome to prepare for Dawn’s arrival, and they spent a morning visiting our observatory in Castel Gandolfo. For reasons ranging from the way they reflect infrared light to the conclusions of computer models for their chemical evolution (including work I was involved with more than thirty years ago), we believe that certain meteorites in our collections are actual samples of … Continue reading

Across the Universe: The Still Voice in the Chaos
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This column first appeared in The Tablet in January, 2010. During the Apollo 17 walk on the Moon, the astronauts collected a rock for the specific purpose of providing samples to pass out to nations around the world. About 200 Apollo 17 samples were distributed in this way. But Robert Pearlman, who runs the space-news website collectspace.com, wrote in 2010 that NASA can now account for only 61 of them. (The one sent to the Vatican resides in our display case at the Vatican Observatory.) I’m not surprised; keeping track of samples is harder than it looks. The humor of the “Night at the Museum” movies comes from the conceit that the specimens in a museum’s display cases are alive, that they get up and move around during the night. Every collector knows that feeling. It’s surprisingly hard to keep our collections in order. One of the little breakthroughs in my own research was finding that a simple measurement of a … Continue reading

Across the Universe: Words that Change Reality
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My columns for The Tablet often act as a diary of sorts, recording important events in science or in my own life. Such is this column, which first ran in September, 2006. Ten years ago last month [2006], Dave McKay and his colleagues at Nasa’s Johnson Space Center in Houston announced that a meteorite, believed to have come from Mars, showed evidence of microbial life. Their interpretations are still widely disputed by the meteoritics community. But, oddly, their announcement resulted in one major change of attitudes. Before, there were still skeptics who were not sure that those rocks came from Mars; now, as the skeptics argue about the putative biogenic grains found in it, no one doubts the Martian origin anymore! Some of us can only be skeptical of one thing at a time, I guess. Still, what you call the meteorite doesn’t really change its nature. Either it is, or it is not, from Mars. Either it is, or … Continue reading