Goodbye – Cassini’s Last Splendiferous Hurrah
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        The English language is lacking in positive affirmations glowing enough to encompass the significance of the Cassini Mission to Saturn. Side winding its way into my mind in the effort to find the right words came a memory of an old TV variety show. In the show, the host announces the artists to perform by pronouncing very large words in rapid precision. Each word is preceded by a judgemental gavel blow. The hyperbolic introductions primed the audience to welcome the splendiferous offerings of the forthcoming show. The pulchritudinous (excellent) nature of the mission has produced an abundance of most noteworthy images. The collection can spectacularly stimulate our senses to levitate our minds and souls. Cassini therefore invites us to relish the beauty of Saturn and its many moons. NASA has magnanimously offered the images videos and gifs to all who wish to enjoy the resplendent wonder of this epic mission. If the same host was to … Continue reading

A Heartfelt Farewell to NASA’s Cassini Mission to Saturn
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The Cassini mission to Saturn ranks right at the top of my list of favorite space missions; this morning, on NASA TV, I watched Cassini’s final moments as it plunged into the atmosphere of Saturn… and I had a good cry. It’s an odd juxtaposition of feelings: being overjoyed and incredibly sad at the same time. When Cassini launched in 1997, my daughters were aged 12 and 9; my wife likes to recall the story of my phoning my eldest in 2004, then in college, to tell her that Cassini was making its orbital insertion burn! She also claims that I can be “such a geek.” Yesterday, I heard a story on NPR with a NASA engineer that was at the very first Cassini planning meeting – 30 years ago! For several people, this mission has been their entire career! In an interview I heard this morning, one mission specialist said that most of what’s in recent science textbooks about … 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: 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

This Post is Heretical! (and best read on long flight)
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This past Spring semester a student in my Astronomy 101 class at Jefferson Community & Technical College here in Louisville asked an interesting question: “Are Star Wars and Star Trek science fiction, or are they fantasy?”  Well, if science fiction requires scientific plausibility, then they are probably fantasy.  Why?  Because they rely on faster-than-light travel.  As best we can tell from the laws of physics, faster-than-light travel and communication are highly problematic from a theoretical perspective.  Moreover, even far slower travel has turned out to be problematic from a practical perspective.  Technology is not advancing in these key areas, and in one way we are significantly retreating.  Technology is endlessly hyped and marketed, so to say such things in today’s culture—or pop culture, if we are thinking of Star Wars and Star Trek—is to speak heresy.  But is it not true? Star Wars and Star Trek are built around an imagined advanced technology that allows for rapid travel and communication … Continue reading

Kicking up some more dust – Apollo 11 Memories part 2
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The Apollo 11 Moon landing in July 1969 had a profound effect on my life. It gave me an interest in astronomy and space that has stayed with me ever since. It has inspired my paintings and my outreach education efforts later in life. In September 1969 I went back to school full of anticipation that my teacher would talk about the biggest global event of the summer. For some reason I truly thought, she would tell us more about it and make a big deal of it in class. No, not a word, not a mention, nothing at all. I was beyond disappointed at the time, that has stuck in my craw ever since. Back in 1969, you did not really engage with your teacher, ask questions or bring up issues. You sat at your desk (wooden with an ink well) with 54 other children and absorbed whatever they dished out. My last year in primary school was in … Continue reading

Across the Universe: Where’s the olivine?
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This column first ran in The Tablet in July 2014 It was a beautiful theory, while it lasted. Most meteorites are well-compressed lumps of primordial dust and little beads of rock. But some are chips of lava, bits of some small asteroid that melted and sorted itself into a small iron core and a crust of frozen basaltic lava. We’ve even seen one such asteroid: the spectra colors of Vesta (the brightest, and second-biggest, of the asteroids) uniquely match these basaltic meteorites [in particular, the Howardite-Eucrite-Diogenite meteorites known familiarly as the HED meteorites]. When a mixture of various minerals gets hot, as inside a volcano, only some of those minerals melt; they make the lava that erupts to the surface, leaving behind other unmolten minerals deep below the volcano. These meteorite lavas should behave the same way. During my student days in the 1970s, we calculated that that for every basaltic meteorite, there should be about four times as much … Continue reading

Kicking up some dust – Apollo 11 Memories Part 1
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July 20 1969, I was  12 years old living in a regular suburban house with regular suburban parents. In my family I the eldest of five at the time. As with most families then we had to be in bed at 8 pm on weeknights, maybe 9.30pm at weekend’s school holidays or not that was the way it was. The Moon landing held a big interest for me, I really wanted to see it. Irish TV (Telefis Eireann) were going to cover the story with a special programme. Much to my surprise, the pestering of my parents in just the right way and at just the right time produced a yes. Deirdre was allowed to stay up and see how the story unfolded. Telefis Eireann didn’t start broadcasting until 6 pm in those days, the Moon landing programme started at 9 pm and was presented by Kevin O’Kelly. We had a small black and white TV with a rabbit-ear aerial. … Continue reading

Jupiter’s Great Red Spot from Juno
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The Juno spacecraft made its seventh close approach (perijove) to Jupiter on July 10th, flying directly over the Great Red Spot. The raw images from the mission are publicly available, and have been post-processed by several different individuals. The results are as beautiful as they are varied. This stunning image, processed by Seán Doran, was featured on the Astronomy Picture of the Day on July 15, 2017: Here are some more examples of post-processing from the imaging community: This image was processed by Jason Major, who runs the fantastic Lights in the Dark website; the image was used in this post by NASA. This video was created using the NASA’s Eyes on the Solar System app shows the Juno spacecraft coming up on the Great Red Spot; I knew the storm was big, but I’ve never seen it from this perspective… it’s BIG! This video gives you a good idea of how close the Juno spacecraft gets to Jupiter during … Continue reading

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