Across the Universe: View from afar
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  This column first ran in The Tablet in February 2013 I traveled to Tucson to measure the fluctuating brightness of some small bodies in the outer solar system using the Vatican’s Advanced Technology Telescope. By how often they brighten and dim, we measure how fast these bodies spin; by how much their brightness changes during these cycles, we get a measure of their irregular shapes. It is not particularly thrilling work. We point the telescope at a given object; take a three-minute exposure with our electronic camera; and then another exposure; and another; and another… These objects typically take about eight hours or more per spin; so we observe one body per night as it rises, crosses the sky, and sets in the west… checking the images for clarity, tweaking the focus, watching the skies to make sure that clouds are not moving in. (We got three clear nights out of five.) Data in hand, our work is still … Continue reading

Across the Universe: Spinning our Hopes
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This article was first published in The Tablet in December, 2005. I also ran it a year ago on this blog, before many of you became regular readers… and before I knew how to embed pictures. So I am running it again, with pictures this time. Every December, along with the Christmas rush and the endless round of holiday parties, planetary astronomers have another deadline facing them: the annual Lunar and Planetary Science conference. The meeting is in March; the deadline for submitting papers is early January. [For 2016, it’s January 12.] It’s challenging enough to write up results on deadline; but what is harder, is that really you ought to have some results worth writing up. My last month has been a scramble as I try chasing after the faintest wisp of an idea to see if it has enough substance to talk about in front of a thousand highly critical peers. Lately [this was 2005] we’ve been observing Centaurs, … Continue reading

Across the Universe: Everything You Know Is Wrong
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Pluto continues to make the news… this column dates from November, 2004, in the Tablet. The latest news from out where Pluto orbits has brought to my mind that ‘60s satire of TV science shows, “Everything You Know Is Wrong.” Readers of this column may remember how surprised we were last spring [2004] to find an object, since named Sedna, orbiting nearly twice as far from the Sun as any previously discovered solar system body. That far away, it must be pretty big to reflect even the meager bit of sunlight that we see glancing off its surface; perhaps as big as Pluto itself? How big? That depends on how bright its surface is. We know from their motions how far away from the Sun (and us) Sedna and the other Trans-Neptunian Objects (TNOs) lie. And we can measure how much light from them reaches our telescopes. For a given brightness, that amount of light could mean they were very … Continue reading

Across the Universe: Tradition… and Pluto
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The imminent flyby of Pluto by New Horizons has brought that Dwarf Planet back into everyone’s mind. The following column was written in 2006, just after the IAU had voted to name Pluto a Dwarf. It ran in The Tablet in August, 2006. Never mind the 2,500 astronomers attending dozens of seminars and joint discussions about stars and galaxies in Prague; the news this week [2006] at the triennial General Assembly of the International Astronomical Union (IAU) is the changing status of Pluto. General Assemblies are different from typical scientific congresses. Rather than being focused exclusively on presenting scientific results, the main point here is to decide on all the arbitrary but necessary definitions that let us talk to each other and understand each others’ data. For example, we’re worrying about tweaking definition of latitude and longitude on the Moon to match the the expected precision of the coming generation of lunar spacecraft from India, China, Japan, and the US. Likewise, defining “what … Continue reading

Across the Universe: The Exploding Centaur
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This column first appeared in The Tablet in April, 2006 It was April Fool’s Day at the Vatican’s telescope in southeastern Arizona, and we’d had three nights of cloudy weather. This night looked promising, however. Bill Romanishin, our colleague at the University of Oklahoma, had given us a list of Kuiper Belt Objects to observe, orbiting out beyond Neptune. Included were some Centaurs, objects that some day might become comets plunging close to the Sun. At the telescope, I was with Steve Tegler from Northern Arizona University. Along with each object, we also observed bits of blank sky, so we could find and remove all the dust spots on the images; and fields of stars whose colours and brightnesses were already well known, so that we could calibrate our objects against these known standards. Around midnight, about halfway into a field of standard stars, Steve looked over his list again and remembered, “Oh, Bill wanted us to try 60558. It’s a Centaur … Continue reading

Encore: Across the Universe: What’s in a Name?
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Encore: on Wednesdays, we repost the best posts from previous months, and make them publicly available. To comment, please see the original post. (A column from The Tablet, first published in March, 2004) On the other side of Neptune live the Trans-Neptunian Objects, or TNOs. They are worlds so faint that to measure their colors, we use a mirror nearly two meters across to gather their light, which we focus into a spot of only a few hundreds of a millimeter, collecting it with an ultra-sensitive electronic chip, over a five-minute time exposure. They move – more than five minutes and the spot turns into a streak. But take enough exposures over a few hours and you can plot their motions against the background stars and galaxies. The TNOs are thought to be the home of a class of comets, and they may represent material that’s been kept in “deep freeze” since the solar system was first formed. Though theorized … Continue reading

Across the Universe: The best way to travel
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First published in The Tablet in January, 2007   Dark and dreary, January is a time to take off to new and exotic climes; or at least, to daydream about such trips. My own January voyage was a visit to my old hometown, snow-dusted Detroit, to attend a science fiction convention. But a panel discussion at that meeting, “Travel Destinations of the Solar System,” challenged us to imagine really exotic localities. Where among the planets would we love to go? And what it would be like to be standing there, in person? Panelist Bill Higgins, a radiation physicist at Fermi Lab in Chicago, regularly presents spaceflight results as a Nasa “Solar System Ambassador” at events like this. He described how Pluto and its moon Charon orbit each other while locked in a spin state that keeps each body always facing the other. “What if we could stretch a “beanstalk” across the 17,000 km gap between them?” he asked. “We could … Continue reading

Across the Universe: What’s in a Name?
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(A column from The Tablet, first published in March, 2004) On the other side of Neptune live the Trans-Neptunian Objects, or TNOs. They are worlds so faint that to measure their colors, we use a mirror nearly two meters across to gather their light, which we focus into a spot of only a few hundreds of a millimeter, collecting it with an ultra-sensitive electronic chip, over a five-minute time exposure. They move – more than five minutes and the spot turns into a streak. But take enough exposures over a few hours and you can plot their motions against the background stars and galaxies. The TNOs are thought to be the home of a class of comets, and they may represent material that’s been kept in “deep freeze” since the solar system was first formed. Though theorized about for years, it’s only in the last decade that new telescopes, more sensitive detectors, and a crew of patient observers have begun … Continue reading