Dawn Probe to Remain in Ceres Orbit
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NASA's Dawn spacecraft has completed its primary mission - to explore the two most massive bodies in the main asteroid belt: asteroid 4 Vesta, and dwarf planet Ceres. After a recent mission extension, Dawn will continue studying Ceres - essentially becoming a long-term reconnaissance orbiter.

One of the advantages of long-term observations is seeing changes that occur over time, as with the seasonally recurring slope lineae on Mars, and fresh impact craters on both the Moon and Mars. There was a brief period of confusion on various social media sites, as rumors that Dawn was possibly going to leave Ceres and fly-by asteroid 145 Adeona, but Jim Green, NASA’s Director of Planetary Science, noted that long-term monitoring of Ceres had more of a potential for significant scientific discoveries than a flyby of Adeona.

Dawn Mission infographic

NASA's Dawn mission exceeded all expectations during its primary mission to Vesta and Ceres. Credit: NASA/JPL-Caltech

Scientists have found permanently shadowed craters on Ceres; if the temperature in these creates remains below -151°C (-240°F), these craters can collect ice. These so-called "cold traps" could have been doing this for billions of years. Scientists will monitor these craters as part of Dawn's extended mission.

Shadowed Craters on Ceres

"Cold trap" craters may have been collecting ice for billions of years. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

High abundances of carbonates in Occator crater (red in the image below) may be the result of  hydrothermal activity within Ceres. The bright patches in Occator represent the highest concentration of carbonate minerals ever seen outside of the Earth.

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/ASI/INAF

The Dawn feed on Twitter is continuously posting spectacular new images from Ceres:

Wothin Zadeni Crater

A moody scene within Zadeni Crater on Ceres. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn currently orbits Ceres at an altitude of 385 km (240 mi).

Position of Dawn spacecraft on July 24, 2016 at 9:19 AM EST. Credit: NASA Eyes on the Solar System / Bob Trembley

Position of Dawn spacecraft on July 24, 2016 at 9:19 AM EST. Credit: NASA Eyes on the Solar System / Bob Trembley

Position of dwarf planet Ceres on July 24, 2016. Credit: NASA Eyes on the Solar System / Bob Trembley

Position of dwarf planet Ceres on July 24, 2016. Credit: NASA Eyes on the Solar System / Bob Trembley

Across the Universe: Three Lunatic Answers
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This column first ran in The Tablet in July 2009

July 20 – the 21st, in Rome – marks the anniversary of the landing of the Apollo 11 astronauts to the Moon. Here are a few lunar topics probably not covered by most folks remembering that event...

Pope Paul VI seeing the moon through the finder of our Schmidt telescope, July 21 [Rome time], 1969

Pope Paul VI seeing the moon through the finder of our Schmidt telescope, July 21 [Rome time], 1969

I saw a photo of Pope Paul VI looking at the Apollo 11 Moon landing through a telescope. Why didn’t he watch it on TV like everyone else? For the Moon landings, world leaders were invited to address the astronauts on a world-wide television link-up, and the Pope read his greetings (in front of a TV) from the Vatican Observatory dome in Castel Gandolfo (in the gardens near the Pope's summer palace). In fact, the system of geosynchronous satellites to send TV pictures live around the world was still pretty new; those of us of a certain age can remember the Beatles introducing All You Need is Love on one of the first Europe/North America TV link-ups, in 1967.

Pope Paul watched the moon landing on TV from our telescope dome, then addressed the astronauts from there

Pope Paul watched the moon landing on TV from our telescope dome, then addressed the astronauts from there

Afterwards, the Pope looked at the Moon through the small finder scope attached to that telescope; that’s the picture all the papers ran. The big telescope itself was actually a camera designed to photograph the sky, with no eyepiece to look through. The Pope’s view of the Moon through the finder scope was delightful, no doubt, but there was no way that even the biggest telescope on Earth could have seen the astronauts themselves. Interestingly, NASA has an orbiter around the Moon now that has imaged the Apollo sites; the landers are still there!

Is there religion on the Moon? Theological discussions of God’s imminence and transcendence aside, the Apollo astronaut Buzz Aldrin did bring with him the communion species from his Presbyterian church near the NASA center in Houston.

This is the chalice that Buzz Aldrin took with him to the Moon

This is the chalice that Buzz Aldrin took with him to the Moon

There are lots of interesting religious questions that come up when you leave Earth and travel to another planet. The Jewish and Islamic calendars are based in part on where the Moon is in the sky; what do you do when it’s not in the sky, but under your feet? It’s easier for Christians; one principle of Pope Gregory XIII’s reform of the calendar in 1582 was to set the date of Easter and other religious holidays not by the position of the Moon but by a mathematical formula anyone can use, anywhere in the world (or off it). It only roughly approximates the “first Sunday after the first full Moon of Spring.”

The Jesuit who helped explain this formula, Christopher Clavius, has a crater named for him on the Moon. So do 35 other Jesuits. How did that happen? The men who made the telescopic map defining the nomenclature we use today were themselves Jesuits. (And they named the Moon’s most prominent crater for Copernicus – this, in Rome, less than 20 years after the Galileo trial.)

Did we really go to the Moon, or was it all faked? I have touched the rocks. I have looked at them through petrographic microscopes, and measured their properties in my lab. They are distinctly different from any Earth rocks, different enough to insure that they are not from this planet. And, for all our work over the last 40 years, we still can’t quite agree about how they were made. If they were faked, whoever did it was cleverer than any of the geologists who have worked on them ever since.

When my colleague Dan Britt got some Apollo samples to measure, he let me hold one...

When my colleague Dan Britt got some Apollo samples to measure, he let me hold one...

That puts me in a privileged position, I know. I believe in the Moon landings because I have seen; most people have to be blessed with believing even though they haven’t seen the direct evidence like I have. Perhaps St. Thomas (the one who doubted) was the first scientist… not because he refused to believe without evidence – a lot of people are quick to doubt – but because when he finally did touch the evidence for himself, he was able to alter his understanding.

Also in Across the Universe

  1. Across the Universe: What’s in a Name?
  2. Across the Universe: Fools from the East
  3. Across the Universe: Hunches
  4. Across the Universe: Desert or a dessert?
  5. Across the Universe: Stardust messages
  6. Across the Universe: The best way to travel
  7. Across the Universe: Original Proof
  8. Across the Universe: Pearls among Swine
  9. Across the Universe: One Fix Leads to Another
  10. Across the Universe: Limits to Understanding
  11. Across the Universe: Words, Words, Worlds: Have We Found Planet X?
  12. Across the Universe: The Glory of a Giant
  13. Across the Universe: Fire and Ice
  14. Across the Universe: Science as Story
  15. Across the Universe: Recognition
  16. Across the Universe: Tending Towards Paganism
  17. Across the Universe: The Ethics of Extraterrestrials
  18. Across the Universe: Orbiting a New Sun
  19. Across the Universe: Seeing the Light
  20. Across the Universe: DIY Religion
  21. Across the Universe: Truth, Beauty, and a Good Lawyer
  22. Across the Universe: Techie Dreams
  23. Across the Universe: By Paper, to the Stars
  24. Across the Universe: Transit of Venus
  25. Across the Universe: Ordinary Time
  26. Across the Universe: Deep Impact
  27. Across the Universe: New Worlds
  28. Across the Universe: Tom Swift and his Helium Pycnometer
  29. Across the Universe: Tradition… and Pluto
  30. Across the Universe: Bucks or Buck Rogers?
  31. Across the Universe: Key to the Sea and Sky
  32. Across the Universe: Off The Beach
  33. Across the Universe: All of the Above
  34. From the Tablet: Tales of Earthlings
  35. Across the Universe: Heavenly peace?
  36. Across the Universe: Help My Unbelief
  37. Across the Universe: Stories of Another World
  38. Across the Universe: Planetary Counsels
  39. Across the Universe: Words that Change Reality
  40. Across the Universe: New Heavens, New Earth
  41. Across the Universe: Souvenirs from Space
  42. Across the Universe: For the love of the stars…
  43. Across the Universe: Spicy planet stories
  44. Across the Universe: Asking the right questions
  45. Across the Universe: Everything You Know Is Wrong
  46. Across the Universe: Errata
  47. Across the Universe: Clouds of Unknowing
  48. Across the Universe: Being Asked the Right Questions
  49. Across the Universe: Recognizing the Star
  50. Across the Universe: Heavenly Visitors
  51. Across the Universe: Christmas Presence
  52. Across the Universe: When Reason Itself Becomes Flesh
  53. Across the Universe: Spinning our Hopes
  54. Across the Universe: Relish the Red Planet
  55. Across the Universe: Obedience
  56. Across the Universe: Traveling Light
  57. Across the Universe: The Still Voice in the Chaos
  58. Across the Universe: Europa
  59. Across the Universe: Defamiliarization
  60. Across the Universe: Forbidden Transitions
  61. Across the Universe: Genre and Truth
  62. Across the Universe: False Economies
  63. Across the Universe: Reflections on a Mirror
  64. Across the Universe: Japan
  65. From the Tablet: Why is Easter So Early This Year?
  66. Across the Universe: Oops!
  67. Across the Universe: Dramatic Science
  68. Across the Universe: Me and My Shadows
  69. Across the Universe: Touch the Sky
  70. Across the Universe: Treasure from Heaven
  71. Across the Universe: Gift of Tongues
  72. Across the Universe: Maverick Genius
  73. Across the Universe: Awareness
  74. Across the Universe: Friends in high places
  75. Across the Universe: A Moving Experience
  76. Across the Universe: Grain of truth
  77. Across the Universe: Clerical Work
  78. Across the Universe: Teaching new stars
  79. Across the Universe: Science for the Masses
  80. Across the Universe: Changelings
  81. Across the Universe: Three Lunatic Answers

View the entire series

Solar Sketching in h-alpha – Prominences dancing on the limb
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Proms-Drawing-WEB

Click on the image to see the sequence of my prom drawings that created the animated gif. See all the movement at the end of this page

Astronomical sketching is not just about drawing pictures it is  about learning. This kind of  sketching is about observing very closely the subject at the far end of your telescope. Sketching at the eyepiece is challenging but  rewarding,  however solar sketching in hydrogen alpha  (h-alpha) is for me the ultimate challenge.  As I have mentioned in another post on sketching  a person does not have to be good at drawing  to produce a  sketch  or learn about a target.

A persons first efforts are not going to be very accurate, whether the target is an apple or the sun. Some increment of wisdom will come with every endeavour . Improvement comes with effort, trial and error over time .

Unlike astrophotography, the sketcher processes the dynamics of the subject in his or her head not in software, however the brain may be a hardware of sorts if one considers all it does for us . The sketcher seizes the moment or the hours on the spot. The sun is so complex ,an ever-changing vista of vigorous motion the action of which appears to be still. In my 40mm Personal Solar Telescope (PST) using an 8mm eyepiece the sun appears to almost fill my field of view . A tiny sphere with enormous and powerful action playing out before my eye. Miniscule filaments belie their size as thousands of miles of plasma behave like ropes twisting wildly in an unimaginable stellar environment.

My first adventures with the sun involved drawing prominences on the solar limb. The movements of these eruptions are not immediately visible because of the 93 million miles between my pupil and our star. The 8mm eyepiece gives me the best view of detail in the prominences and allows me to sketch accurately. This eyepiece coupled with a continuing a fine balancing act between focusing and tuning enables me to see the shapes the gasses make as they move. It allows me to observe  their anchor points and sometimes their disconnecting events as they leave the sun.

Because the seeing conditions can change very often during an observation it is important to adjust the focus regularly. Tuning also needs altering during the sessions in order to keep the action sharp and see the best image possible. With a h- alpha telescope one can see some detail on and around sunspots, the umbra's, penumbra's and the shape of the spots themselves. Active regions are very detailed , fibrils, plage, and flares all combine with the dark sunspots to make these areas a challenge to capture. Prominences on the limb and filaments against the disc can lure your eye into a task that can be forever daunting. So that is most likely why I began my solar sketching with just prominences off the limb as it seemed to be the easier choice as opposed to trying to capture the entire commotion on the disc.

I remember being both amused and delighted when I found out that particular shaped prominences have specific names such as broccoli proms and hedgerow proms. Prominences can also look like trees with many branches. They can present as complex loops within loops as the electrified plasma follows and reveals the invisible magnetic field lines which are present but hidden to our eyes.

In order to show movement over time with proms on the solar limb it is necessary to draw a sequence of sketches over the course of several hours. As you can see in the drawings above there is a sequence of sketches between 10:50 UT and 19:50 UT May 15th 2008 . Conte sticks on black card give the best edge for drawing these , however I have also used ink on white paper with a fine brush from time to time. This sequence was animated via Photoshop by a friend using my still photographs of the proms . You can see the proms over time moving and swaying like trees in a storm. Another method to produce a relatively fluid sequence set is to use one of the many free gif makers online . iMovies on a Mac can also create mini films if you use a tight transition.

Animated Gif of all Deirdre's the prom sketches above. Gif made in Photoshop by Sally Russell

Radio Eyes on the Sky
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Historically radio astronomy held a rather modest place. Around 40-50 years ago it was thought that only a few objects in space would emit radio waves strong enough to be detected by receivers on Earth, thereby making it not profitable to build radio telescopes at all.

This conclusion was incorrect not because astronomers made mistakes with computing the numbers, but because the majority of sources had not yet been discovered. Now we know that all galaxies emit radio waves at some level, and that certain types of galaxies are powerful sources, the so-called radio galaxies. The strong radio emission is thought to be produced as a result of the violent process of material in-falling into the center onto supermassive black holes.

Even apart from the fascinating radio galaxies, radio astronomy is interesting because this particular color of light has the longest wavelengths, from millimeters to kilometers in size. The great benefit of such long wavelengths is that other telescopes that operate at the same wavelengths can be used contemporaneously to give an effective telescope size equal to the distance between the two telescopes!

This trick of ‘phasing’ the light can only work for radio telescopes, and allows us to see fine details of distant objects such as the accretion disks of the most powerful supermassive black holes in the centers of radio galaxies.

At the same time, there is the cost that the collecting area of the two telescopes involved is equal only to the meager sum of the area of the two dish receivers. This drawback allows only the strongest of radio signals to be detected. How can we discover the vast majority of the galaxies which are too faint to detect with current technology?

There is a massive project underway to build the “Square Kilometer Array” (SKA). SKA uses the trick of phasing the wavelengths detected by multiple radio receivers all observing the same object at the same. It gets past the problem that radio emitters in space tend to be faint by assembling a great many receivers into its array.

The SKA has 16 telescopes all working collectively at present, and by 2030 will consist of thousands of radio antennas spread out over a large distance extending from South Africa to Australia. With it, we should be able to detect the atomic element hydrogen present at the time the first stars were made in the universe.

From the Cabinet of Physics: Conveying Heat across Space
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Today's demonstration from the Cabinet of Physics appears at first to be about optics but, in a surprising twist (SPOILER ALERT), turns out to be about heat.

A curved mirror, a paraboloid, reflects the light of a candle flame to another curved mirror some distance away. The candle sits at the focal point of the first mirror. The second mirror brings the light to its own focal point; hold a white card at this precise spot, and you'll see an image of the candle flame.

Now the candle is replaced by a collection of burning lumps of charcoal. Across the room, a piece of tinder is placed at the focus of the second mirror. To the eye, the coals seem much dimmer than the candle flame. The mirrors are gathering not only the visible light, but also the more copious invisible infrared light emitted by the coals.

The unseen radiant heat is energetic enough to ignite the tinder. Soon it too is glowing red, and smoke is rising. It's a nice example of the close kinship between light and radiant heat.

Perhaps the novelist H. G. Wells had a demonstration like this in mind in 1897 when, in War of the Worlds, he imagined Martian invaders incinerating the English landscape with "heat rays."

This apparatus reminds me of a story. The physicist Theodore Taylor was responsible for a most peculiar application of focused heat radiation. At an observation post in a Nevada desert on 5 June 1952, Taylor was waiting for the test of a nuclear bomb he had designed.  He took a small parabolic mirror and attached a rig, made out of wire, that could hold the tip of a cigarette at the mirror's focal point.   He aimed the mirror carefully at the distant weapon. At the end of a countdown, intense visible and infrared light engulfed the test site. Miles away, Taylor withdrew his Pall Mall from the mirror and took a puff. He had invented the first nuclear-powered cigarette lighter.

The Foundation for Science and Technics, or Fondazione Scienza e Tecnica, of Florence, Italy, has made available many videos exploring the Cabinet of Physics, a large collection of antique scientific demonstration instruments.  The Foundation's homepage may be found here, and its Youtube channel, florencefst, here.

Across the Universe: Changelings
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This column first ran in The Tablet in July 2010

In 1803, a team of French scientists investigated a fall of meteorites near the town of L’Aigle, and concluded that they were indeed samples from outside of Earth. It was a revolution comparable to Copernicus’: the Earth we live on does not exist isolated from all the other planets.

NGC 609 is an open cluster of young stars, siblings formed at the same time. Stars like our sun form in these sort of clusters. Early in their lifetime, when they were still close to each other, they may have shared and swapped comets from system to system. The water we drink on Earth may come from another own solar system! (VATT image)

NGC 609 is an open cluster of young stars, siblings formed at the same time. Stars like our sun form in these sort of clusters. Early in their lifetime, when they were still close to each other, they may have shared and swapped comets from system to system. The water we drink on Earth may come from another own solar system! (VATT image)

Well, at least, not isolated from the asteroids, whose chips may come to us in the form of meteorites or, more often, as harmless showers of meteors. Surely the real planets, orbiting in simple, stable paths far from Earth, don’t touch us.

But about sixty years ago, we finally realized that some bits of outer space bigger than dust or rocks manage to hit us, exploding on impact with the energy of nuclear bombs, leaving giant craters. Thirty years ago, we came to admit that one that hit 65 million years ago was big enough to wipe out the dinosaurs. (About that time we also found meteorites from the Moon and Mars.)

Then, twenty years ago came the discovery of planets around other stars. Yes, Earth sits in a “Goldilocks” orbit, not too cold and not too hot, around our Sun; and the other planets in our system are comfortably far away from us, so that their gravitational pull is not likely to move us out of this comfort zone. But in the thousands of other planetary systems about other stars, such simple near-circular orbits are a rarity. Most planetary systems are far more chaotic.

About ten years ago, computer models for the orbits of the planets in our own solar system showed that it was itself once just as chaotic.

Since the mid 1800s we’ve known that orbits of the asteroids between Mars and Jupiter have been shaped by Jupiter’s gravity, which has tossed most of those bodies out of our own solar system. But conservation of momentum and energy means that as the asteroid debris was scattered outwards, Jupiter must have been moving inwards. That means there would have been a time when Jupiter wound up in an orbit (not all that far from where it is now) in a resonance with Saturn. And just as playing a musical note in resonance with the natural vibration of a glass causes it to shatter, having Jupiter pull on Saturn at a frequency in resonance with Saturn’s orbit would have shattered its orbit into a very eccentric path, one that in turn would have scattered Uranus and Neptune out to their present positions in the outer solar system. We can even see evidence for that scattering in the pattern of orbits of the newly-discovered trans-Neptunian objects, the thousand icy asteroids out where Pluto orbits.

In June [2010], at a workshop in Philadelphia on these trans-Neptunian objects, two more consequences of this game of orbital billiards were explored. One new model suggested that Uranus and Neptune weren’t the only giant planets moved about by Saturn during this episode. It proposed that another giant planet, formed with them, got itself completely ejected from our solar system during that time.

Even more startling was the suggestion that such episodes were also occurring in the other stars of the cluster from which our own Sun was formed. (We know stars are formed in clusters with hundreds of members; the Pleiades, visible to the naked eye, are an example of such a star cluster.) It could be that a lot of the comets in our own solar system started out as pieces of other stars’ systems.

Those comets may well have been the source of the water and carbon on Earth today. Our home planet has not merely been touched by other planets; our very bodies may be made from the ices of other stars.

The greater universe does not merely touch us. It is us.

Also in Across the Universe

  1. Across the Universe: What’s in a Name?
  2. Across the Universe: Fools from the East
  3. Across the Universe: Hunches
  4. Across the Universe: Desert or a dessert?
  5. Across the Universe: Stardust messages
  6. Across the Universe: The best way to travel
  7. Across the Universe: Original Proof
  8. Across the Universe: Pearls among Swine
  9. Across the Universe: One Fix Leads to Another
  10. Across the Universe: Limits to Understanding
  11. Across the Universe: Words, Words, Worlds: Have We Found Planet X?
  12. Across the Universe: The Glory of a Giant
  13. Across the Universe: Fire and Ice
  14. Across the Universe: Science as Story
  15. Across the Universe: Recognition
  16. Across the Universe: Tending Towards Paganism
  17. Across the Universe: The Ethics of Extraterrestrials
  18. Across the Universe: Orbiting a New Sun
  19. Across the Universe: Seeing the Light
  20. Across the Universe: DIY Religion
  21. Across the Universe: Truth, Beauty, and a Good Lawyer
  22. Across the Universe: Techie Dreams
  23. Across the Universe: By Paper, to the Stars
  24. Across the Universe: Transit of Venus
  25. Across the Universe: Ordinary Time
  26. Across the Universe: Deep Impact
  27. Across the Universe: New Worlds
  28. Across the Universe: Tom Swift and his Helium Pycnometer
  29. Across the Universe: Tradition… and Pluto
  30. Across the Universe: Bucks or Buck Rogers?
  31. Across the Universe: Key to the Sea and Sky
  32. Across the Universe: Off The Beach
  33. Across the Universe: All of the Above
  34. From the Tablet: Tales of Earthlings
  35. Across the Universe: Heavenly peace?
  36. Across the Universe: Help My Unbelief
  37. Across the Universe: Stories of Another World
  38. Across the Universe: Planetary Counsels
  39. Across the Universe: Words that Change Reality
  40. Across the Universe: New Heavens, New Earth
  41. Across the Universe: Souvenirs from Space
  42. Across the Universe: For the love of the stars…
  43. Across the Universe: Spicy planet stories
  44. Across the Universe: Asking the right questions
  45. Across the Universe: Everything You Know Is Wrong
  46. Across the Universe: Errata
  47. Across the Universe: Clouds of Unknowing
  48. Across the Universe: Being Asked the Right Questions
  49. Across the Universe: Recognizing the Star
  50. Across the Universe: Heavenly Visitors
  51. Across the Universe: Christmas Presence
  52. Across the Universe: When Reason Itself Becomes Flesh
  53. Across the Universe: Spinning our Hopes
  54. Across the Universe: Relish the Red Planet
  55. Across the Universe: Obedience
  56. Across the Universe: Traveling Light
  57. Across the Universe: The Still Voice in the Chaos
  58. Across the Universe: Europa
  59. Across the Universe: Defamiliarization
  60. Across the Universe: Forbidden Transitions
  61. Across the Universe: Genre and Truth
  62. Across the Universe: False Economies
  63. Across the Universe: Reflections on a Mirror
  64. Across the Universe: Japan
  65. From the Tablet: Why is Easter So Early This Year?
  66. Across the Universe: Oops!
  67. Across the Universe: Dramatic Science
  68. Across the Universe: Me and My Shadows
  69. Across the Universe: Touch the Sky
  70. Across the Universe: Treasure from Heaven
  71. Across the Universe: Gift of Tongues
  72. Across the Universe: Maverick Genius
  73. Across the Universe: Awareness
  74. Across the Universe: Friends in high places
  75. Across the Universe: A Moving Experience
  76. Across the Universe: Grain of truth
  77. Across the Universe: Clerical Work
  78. Across the Universe: Teaching new stars
  79. Across the Universe: Science for the Masses
  80. Across the Universe: Changelings
  81. Across the Universe: Three Lunatic Answers

View the entire series

The Modern Solar System, the Diversity of Worlds, and William Whewell (II)
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Last week I introduced readers to a newly published paper by Michael J. Crowe entitled “William Whewell, the Plurality of Worlds, and the Modern Solar System.” Crowe is the Rev. John Cavanaugh, C.S.C., Professor Emeritus in the Program of Liberal Studies and the Graduate Program in History and Philosophy of Science at the University of Notre Dame, and one of a relatively small number of scholars who study the history of human thought concerning intelligent life on other worlds, and Crowe suggests that Whewell (1794–1866), Master of Trinity College of Cambridge University, was the first person to envision the modern solar system.  As noted last week, from Copernicus up through the early nineteenth century astronomers assumed that intelligent life was abundant outside of Earth—and in particular, abundant within the solar system.  To use the language of the times, they believed in a “Plurality of Worlds” like Earth.

Of course today we know that the solar system is not full of worlds like Earth.  We have so far found no extraterrestrial life at all within the solar system.  We do not expect to find any intelligent life here, and it is possible we will never find any extraterrestrial life of any sort within the solar system.

Crowe notes that in 1853 Whewell anonymously published his Of the Plurality of Worlds: An Essay, attacking the idea of a universe widely inhabited with intelligent life.  Crowe writes that a key argument of Whewell’s was applications of the inverse-square-law as it relates to gravitational force, light, and heat radiation.  This is the law that says that if planet B is twice the distance from the sun as planet A, it will receive one quarter the heat and light from the sun, all else equal.  Thus, were the Earth a little closer to the sun, or a little further away, it would be significantly hotter or colder than it is now.  Crowe argues that Whewell was one of the first people to consider the idea of a “habitable zone” around a star—an idea he put forward in the Essay.  Whewell also used geology to argue against widespread extraterrestrial intelligence.  Crowe notes that Whewell had been elected president of England’s Geological Society and that—

Whewell’s argument was that evidence for the age of the Earth showed that throughout most of Earth’s history it had been bereft of intelligent life, which suggested that the Creator’s plan for the cosmos was capacious enough to leave vast regions of it lacking ETIs [intelligent extraterrestrials] for long periods of time.

Whewell did not rule out the idea of lower life forms within the solar system.  For example, he speculated on life existing on Jupiter, writing that Jovian life forms might be “aqueous, gelatinous creatures; too sluggish, almost, to be deemed alive, floating on their ice-cold water, shrouded forever by their humid skies.”  However, time has not been good to even the idea of lower forms of extraterrestrial life within the solar system; were we to find even a microscopic gelatinous creature on Mars, that would be considered a monumental discovery.

Huygens diagram.

Huygens diagram.

Crowe argues that the evidence for a diversity of worlds—that is, for planets that are not like Earth, as opposed to planets that are like Earth—was present long before Whewell.  For example, Christiaan Huygens, in the same later seventeenth-century book in which he wrote—

A Man that is of Copernicus's Opinion, that this Earth of ours is a planet, carry'd round and enlighten'd by the Sun, like the rest of them, cannot but sometimes have a fancy, that it's not improbable that the rest of the Planets have their Dress and Furniture, nay and their Inhabitants too as well as this Earth of ours: Especially if he considers the later Discoveries made since Copernicus's time of the Attendents of Jupiter and Saturn, and the Champain and hilly Countrys in the Moon, which are an Argument of a relation and kind between our Earth and them....

—includes a fairly accurate diagram of relative sizes of the planets.  Likewise, says Crowe, Isaac Newton included in the third edition of his Principia calculations showing the substantial differences in the mass, density, and surface gravity of different solar system bodies.  Both Huygens’ diagram and Newton’s numbers illustrate planetary diversity, not planetary homogeneity.  They in fact suggest reason to admit that, unlike our Earth, the other planets might be devoid of dress and furniture and inhabitants.

From the Principia.

From the Principia.

But Huygens and Newton lived a century prior to Whewell.  Why did Whewell come to reject the idea of a plurality of worlds when so many others did not?  Crowe argues that what brought on Whewell’s resistance to the idea was that Whewell, a priest in the Church of England, came to believe that a plurality of worlds posed problems for Christianity.  For, he said, Earth is—

the Stage of the Great Drama of God’s Mercy and Man’s Salvation; the Sanctuary of the Universe; the Holy Land of Creation; the Royal Abode, for a time at least, of the Eternal King. This being the character which has thus been conferred upon it, how can we assent to the assertions of Astronomers, when they tell us that it is only one among millions of similar habitations...?

Thus Crowe argues that Whewell’s religious convictions prompted him to question the ruling paradigms of the day (the “Copernican Principle” that said there is nothing special about Earth, and the “Principle of Plenitude” that said that God or Nature would not waste the efforts involved in producing the universe without placing within it widespread intelligent life) and to look at the existing data in a new light.  Whewell wrote, “I obtain my views of the physical universe from the acknowledged genuine sources: observation and calculation.”

Whewell was right, and those who argued that the solar system would abound with intelligent life were wrong.  Crowe concludes that Whewell’s work played a key role in our coming to the modern view of the solar system as “a rather desolate place.... wherein there is intelligent life but only on one object, and that object of rather unimpressive size.”

Patience, Patience, Patience: Why Haven’t We Heard Much From Jupiter?
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Any international trip involves overcoming a universal problem: Jet lag. Having traveled from the United States to Rome on a few occasions, I find the best approach to overcoming jet lag is to stay busy until evening on the day you arrive. After arriving at Fiumicino airport, I jump on the train, check into my hotel, get back on the train or bus, visit St. Peter’s Basilica, and then just walk for the rest of the day, camera in hand, doing my best impression of an over-zealous American tourist in Vatican Square. When night comes, I am exhausted, but always ready to face the new day in the morning. These first moments of arrival are an essential part of a successful trip to Rome, but often are not the most memorable. The memorable moments come with time, exploration, and surprises that didn’t make the initial itinerary. I think many of us, myself included, have adapted this “let’s get busy right away” … Continue reading

From the Cabinet of Physics: Joule, Electricity, Heat, and Light
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The English physicist James Prescott Joule (1818 – 1889) spent a lifetime working to understand the behavior of energy in its many forms. Today the Cabinet of Physics explores the Joule Effect, which concerns the connection between electricity and heat. Joule showed that the heat energy created by electrical current passing through a circuit is proportional to the the square of the amount of current, and also proportional to “resistance,” a measure of the ease with which current passes through a circuit. Copper is a pretty good conductor, but nonetheless a copper wire has some resistance, and will heat up if we send many amperes of current through it. In today’s video the copper wire gets hot enough to give off a dull red glow. It’s not a very useful light source, but it’s a hint toward the invention of an incandescent light. Of all metals, silver is the best at conducting electricity in a circuit like this one,* so … Continue reading

Stars Wonderful Stars at Wexford Town Library Ireland
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On a dull and drizzle splashed day in Wexford, children came to the local library to learn about our magnificent star. They were taking part in a new initiative run by Libraries Ireland , a national reading plan for children in the Summer months. The idea is that the children read at least six books and collect small encouraging rewards along the way culminating with an awards event at the end. ‘Summer Stars’ is the name of this year’s programme and of course my workshop, ‘Stars Wonderful Stars’ was a perfect fit. My workshops always begin with an explanation of what we will try to do and how we will go about our efforts . Stressing the importance of our star in everyday life is paramount in my initial presentation. Making sure the children understand the very special existence of our Earth in relation to the Sun is central. Pointing out the fact that we do not have to wear … Continue reading

Tidal Disruption Event: How a Black Hole “Eats” a star
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We cannot see black holes in the sky because they are completely dark. They do not shine like a star, nor do they even emit radiation like a planet. They do consume light and matter, which makes them ever so interesting to astronomers and the public alike. For example, if we were to shine a flashlight at a black hole the light would not reflect back at us or get re-emitted at some other wavelength. It would just disappear. As such, it is a challenge to find them. We do think that massive stars are capable of becoming black holes at the end of their lives, and that these stellar mass black holes can grow by gathering up the material that falls onto them. There is the common misconception that black holes “vacuum” up any material that gets near it. This is actually not the case. A person can lead a relatively normal life on a planet in orbit about … Continue reading

Across the Universe: Science for the Masses
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This column first ran in The Tablet in July 2008 [In July 2008], the members of the Vatican Observatory spent a week contemplating our hopes and plans for the future while enjoying the views from an Italian retreat house in the Abruzzi. The highlight of the week was a visit from the then newly-elected Jesuit Father General,  Fr. Adolfo Nicholás. In preparation for the General Congregation that elected him, we had prepared a number of documents suggesting that the Jesuit order take more notice of science and technology, both to answer the kinds of science and religion questions we get asked all the time, and to better minister to the growing number of people (in places like India, never mind the industrialized West) who make their living with computers and other high-tech equipment. It turns out, Fr. Nicholás had read those documents. When he spoke to us, he suggested that a new Jesuit order of studies should be developed that incorporates … Continue reading