Could “Planet Nine” be Considered a Planet?
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I got to wondering: given the International Astronomical Union’s (IAU) current definition of a planet, if a hypothesized “Planet Nine” were to be found in the outer reaches of our solar system, could it (or anything in that region) be considered “a planet?” The IAU definition of a planet is a celestial body that: (a) is in orbit around the Sun. (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape. (c) has cleared the neighborhood around its orbit. An astronomical units (AU) is a unit of measurement equal to the mean distance from the center of the earth to the center of the sun – 149.6 million kilometers. The Kuiper belt is a disc-shaped region of icy bodies in the solar system – including dwarf planets such as Pluto – and comets beyond the orbit of Neptune. It extends from about 30 to 55 AU. A trans-Neptunian object (TNO) is any … Continue reading

Kepler Team Releases Catalog with 219 new Exoplanet Candidates
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The story of the Kepler space telescope is a saga of discovery, heartbreak, and redemption. Launched in 2009, Kepler’s mission was to search for Earth-size and smaller planets orbiting nearby stars, and to estimate how many stars in the Milky Way have such planets. Within the first few weeks of observations, five previously unknown exoplanets were found orbiting close to their parent star. Over the next few years, thousands of planetary candidates were discovered. In July of 2012, one of the telescope’s four reaction wheels failed; these are a type of flywheel that keep the spacecraft pointed at its target, and the telescope needs three to function properly. In May of 2013 a second reaction wheel failed, ending new data collection for the original mission and putting the continuation of the mission into jeopardy. In November of 2013, a new mission plan dubbed K2 “Second Light” was devised – by balancing “light pressure” from the Sun on spacecraft’s solar panels to act as a … Continue reading

Across the Universe: Ephemeral science
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  This column first ran in The Tablet in June 2016 Over the past thirty years the Vatican Observatory in Castel Gandolfo has been hosting a biennial summer school, where we invite young scholars from around the world to spend four weeks with us, exploring in depth some topic in astrophysics. [The 2016] school was centered on water in the solar system and beyond. It’s an area that I’ve worked in since I was a young scholar myself; my master’s thesis, now more than 40 years old, was all about Jupiter and Saturn’s icy moons. All of my work on the topic, of course, is long obsolete. Just four years after I had made my computer models to predict what we’d see at those moons, the Voyager spacecraft actually visited Jupiter and revealed its moons to be worlds far more elaborate than anything I could have proposed. Still, the basic science hasn’t changed; at our school we taught how to use properties like … Continue reading

Asteroid Day 2017
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It’s June, Asteroid Day approaches! Asteroid Day is a global coalition of scientists, astronauts, physicists, artists, musicians and concerned citizens that have come together to focus the world’s attention on the nature of asteroids, and the solutions that could protect all life on Earth from future asteroid impacts, and inspire the next generation. Since the summer of 2015, worldwide Asteroid Day events have been held on June 30th, the date of the historic Tunguska Impact Event of 1908. The founders of Asteroid Day drafted the 100X Declaration. In short: Over the last decade and a half, we’ve discovered a LOT of near-Earth asteroids, and continue to do so. Some of these asteroids can potentially impact the Earth. Some of these asteroids are large enough that an impact would be “a bad thing.” We need to accelerate the discovery and tracking of Near-Earth Asteroids to 100,000 per year within the next ten years. We need to get government, private and philanthropic organizations … Continue reading

New Cassini Module in NASA Eyes App
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The new Cassini Mission module is live in the NASA Eyes on the Solar System app! The module is JAM-PACKED with features, including a cinematic simulation the entire 20-year mission, images of Saturn, its rings and moons, an interactive timeline – where you can follow the spacecraft throughout its mission, and simulations of several Cassini Grand Finale events. NASA Eyes is a free app for the PC/MAC and a GREAT educational tool. With NASA Eyes, you can go to any planet in our solar system, many moons, asteroids, and comets. You can zoom to several different active space missions, and simulate what they are doing in real-time, or fast-forward or backward to any point in their mission; several missions have built-in tours – like Cassini. There’s a module about the 2017 eclipse, and the Eyes on the Earth module has several different visualizations of climate data. The Eyes on Exoplanets module lets you zoom to hundreds of different exoplanet systems, see what … Continue reading

Eta Aquariids Meteor Shower 2017
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The Eta Aquariids meteor shower appears strongest when when viewed from the southern tropics. From the equator northward, the shower typically produces only medium rates of 10-30 per hour just before dawn. Meteor activity is good for a week centered the night of peak activity. These meteors travel at a high rate of speed, and produce a good percentage of persistent trains, but few fireballs. Peak: May 6-7th Active from: April 19th to May 26th Radiant: 22:32 -1° (see image above) Hourly Rate: 55 Velocity: 42 miles/sec (swift – 66.9km/sec) Parent Object: 1P/Halley The moon will be a waxing gibbous, setting around 4:00 AM. Source: American Meteor Society … Continue reading

Across the Universe: Perturbing the Universe
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  This column first ran in The Tablet in April 2014 A member of our Vatican Observatory community, Fr. Bill Stoeger, died of cancer last month [2014]. I could say that Bill was both the smartest man and the holiest man I have known; but he would have rejected that characterization out of hand. So I will only say that his goodness and his genius never ceased to move me. He’s the only person I know who could work the mathematics of the Big Bang, and also direct retreats for religious women. Bill’s religious faith did not control the science he did, but how he did it. For example, more often than not he collaborated with scientists from the developing world – South Africa and Brazil in particular. And he showed a special patience with those members of our scientific community who could be brilliant but eccentric and sometimes hard to deal with. His scientific output was astonishing. At Cambridge … Continue reading

Lyrids Meteor Shower 2017
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The Lyrids meteor shower is a medium strength shower that typically produces good rates for three nights centered on the maximum. These meteors usually lack persistent trails, but have been known to produce fireballs. This shower is best seen from the northern hemisphere, where the radiant is high in the dawn sky. This shower can be seen from the southern hemisphere, but at a lower rate. Peak: April 21-22nd Active from: April 16th to April 25th Radiant: 18:04 +34° (see image above) Hourly Rate: 18 Velocity: 30 miles/sec (medium – 48.4km/sec) Parent Object: C/1861 G1 (Thatcher) The moon will be a waning crescent, rising shortly before dawn. Source: American Meteor Society … Continue reading

Across the Universe: Maybe
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  This column first ran in The Tablet in April 2013 The Kepler Space Telescope, monitoring a hundred thousand stars to catch the faint flickers of light that might indicate the shadows of planets, announced [April 2013] the discovery of a star that may have two super-Earths orbiting within its “Goldilocks zone.” That’s the distance from the star where liquid water should be stable. The idea of a system with two planets that could harbor life brings up all sorts of exciting science-fictional possibilities. Well, maybe. We don’t know for sure yet that either planet really is Earth-like; they could be small gas balls. We don’t know yet if either planet has an atmosphere, much less the sorts of chemicals we associate with life. And after all, our own solar system has two bodies within its Goldilocks zone – Earth and its Moon – but only one has life. For that matter, Mars is close enough to that stable zone … Continue reading

Strange Tales of Galileo and Proving: Omitted Data and the Tides
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Last week I wrote a post on how even books for children and travel books state (incorrectly) that Galileo proved that the Earth circles the sun, as Copernicus had said it did.  This post tells a strange story about Galileo’s efforts to prove that the Earth circles the sun. In Galileo’s time, no telescopic observation was likely to prove Earth’s motion.  Before the telescope had even been invented, Tycho Brahe had proposed a geocentric theory in which the planets circled the sun while the sun, moon, and stars circled the Earth.  Brahe’s theory was mathematically and observationally identical to Copernicus’s heliocentric theory insofar as the Earth, sun, moon, and planets were concerned: the “machinery” of both systems was the same, it was just that in Brahe’s the Earth stood still, whereas in Copernicus’s the sun stood still.  Galileo’s telescopic observations proved that Venus circled the sun—but Venus circled the sun in both Brahe’s geocentric theory and in Copernicus’s heliocentric theory.  … Continue reading

Grand Finale – Painting inspired by the Cassini Mission to Saturn
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Also in Exploring the Solar System Exploring the Solar System: The Mass of the Sun Marvellous Mars Drawing Workshop at Dunsink Observatory Dublin Astronomical Sketching – Education in action Stars Wonderful Stars at Wexford Town Library Ireland Get ready the Perseids are coming Space the final Frontier – World Space Week 2016 On the richness of the lunar surface Dark Sky Magic at Ballycroy National Park Mayo Ireland Grand Finale – Painting inspired by the Cassini Mission to Saturn Cosmic Lobster Pot A Slice of Solar Drawing in h-alpha View the entire series … Continue reading

Across the Universe: Faith and Expectations
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This column first ran in The Tablet in March 2013, soon after the election of Pope Francis How do I feel about a Pope who is not only a fellow Jesuit, but one who’s studied science (in his case, chemistry) as well? To be honest, I am terrified. For the past twenty years I have lived off the expectations that others have of Jesuits and scientists; now I am going to have to deal with someone who can see past the mystique. Familiarity breeds a certain discomfort. I can only imagine what it’s like for our Observatory’s director, Fr. Funes, who is himself not only a Jesuit and scientist but also from Argentina. [In fact, as it later came out, when José first began the process of entering the Jesuits as a young man, one of the Argentinian Jesuits who interviewed him was a certain Father Bergoglio…] Pope Francis’ chemistry background has not gone unnoticed in the scientific world. A … Continue reading