On My Bookshelf: Are We Being Watched?

I just finished Paul Murdin’s 2013 book, Are We Being Watched? The subtitle gives it away as a science book, not conspiracy theory: The Search for Life in the Cosmos.

An astronomer pens a book that amasses planetary science, geology, chemistry, history of science, and significantly, biology. Dr Murdin is an excellent writer, and except for a few small factual burps (like Jupiter’s moon Callisto being the size of the moon–it’s not) this is a very informative book. It succeeds for being an intelligent and readable work without dumbing it down. Though a reader’s science background will make it very digestible.

On the plus side, the author takes the reader through many sciences in exploring the possibility for life off Earth. His chapter summarizing the search for life on Mars is about the best treatment I’ve read of a subject I’m not sure I ever understood very well. Especially the question about the Viking landers: what the heck did they find in 1976?

Count me as a skeptic on the likelihood of finding intelligent life elsewhere in the universe. I’m a proud member of the Rare Earth club. Aliens are not watching us. I feel pretty solid on that. But I enjoyed this book because of a calm, reasoned, and thorough examination of the multiple scientific disciplines that modern astronomy brings together to address the question.

 

Satellite Imagination: Pioneer’s Near Miss

In 1961, UCLA grad student Michael Minovitch (image here) figured out the gravity assist maneuver for space travel. The young mathematician, working for the Jet Propulsion Laboratory (JPL), crunched some numbers. And the numbers showed that if a rocket was aimed carefully at a planet at just the right time, its course could be bent to arrive at a second planet with a savings in both fuel and time.

A few years later, another grad student spending his summer at JPL, Gary Flandro (image here), was tasked to design some exploratory missions to the outer planets: Jupiter, Saturn, Uranus, and Neptune. He noticed that all four of them would align in the late 70′s to permit one space probe to visit two, three, or even all four of them. And better yet, it could get to Neptune in something like twelve years, as opposed to forty or more if it flew there unassisted. It seemed too good to be true. But NASA had to get hopping. These alignments only occurred every two centuries. Could they put a mission together in a decade?

In those days, NASA had just gotten its feet wet with single-planet missions. Mariner 2 flew by Venus in 1962 and Mariner 4 visited Mars in passing three years later. But eventually the muckety mucks came around and the Grand Tour was rolled out for congressional approval in 1971. The following year, its budget was sliced, and scientists cut back from four to two planets, and from four to two probes.

On the bright side, Dr Flandro’s idea was successfully employed as the 10th Mariner, aimed first at Venus, and later gave us our first close-up views of the planet Mercury.

So the JPL scientists poured their efforts into Voyager space probes to each visit Jupiter and Saturn. They secretly kept their options open for Uranus, Neptune, and Pluto. But they didn’t tell Congress.

To guide this “stealth” mission to the way-out planets, Voyager would have to survive a fairly close pass to Saturn’s rings. Potential problem: Saturn is almost a billion miles away. And what if Saturn’s neighborhood were messy with ring debris and other gunk? The JPL Voyager folks needed a sacrificial lamb, a test project to clear the road, as it were. They found one in Pioneer 11. (Artist’s depiction below.)

Pioneers 10 and 11 were not JPL projects. These explorers were managed by the Ames Research Center. Northern California. The Jet Propulsion Laboratory is Pasadena. SoCal. Can you smell rivalry?

I recommend Mark Wolverton’s The Depths of Space: The Story of the Pioneer Planetary Probes. Excellent book. Tells a great story. The eleventh Pioneer was the crowning achievement of that series. And its Silicon Valley handlers weren’t excited about sacrificing their probe for the sexy, souped-up Voyagers.

The Pioneer project began as inner solar system explorers–built with economy, and aimed at studying the sun and the space between the inner planets. They scored big time to put together NASA’s first mission beyond the asteroid belt. Unlike what you see in Star Wars and Star Trek, navigating the sun’s asteroid belt isn’t evasive maneuvers. But still, people weren’t sure about things like small particles, meteors, and such. Maybe the intrepid Pioneers couldn’t make it to Jupiter.

But they did.

After a successful Pioneer 10, Ames Research Center decided to pull a Gary Flandro. They stole a page from JPL and targeted their Pioneer 11 mission 43,000 miles above the cloud tops of Jupiter, bending its trajectory over the orbit plane of the planets (right) to aim at Saturn which then, was on the opposite side of the sun from target number one.

I can imagine the JPL crew was a little pee-oh’ed at getting beat to a second planet. They had designed the Grand Tour mission, and the resulting Voyagers which weren’t due to launch until 1977. Here this little upstart 600-lb weakling was going to get a first look at Saturn. And it relied on the JPL imagination of Gary Flandro, the guy who originally imagined multiple-planet missions.

But Pioneer 11 has to survive an extra five year jaunt. And whatever mess is to be found near Saturn’s rings.

If you’ve been following this series, by now you’re probably wondering where the satellites enter the show. Well, look at the pair there on your left.

In the 1960′s these two satellites were imaged from earthbound telescopes. But astronomers lacked the imagination to think of two bodies sharing nearly the same orbit. None of the observations worked out, so that expected one moon inside the orbit of Mimas was a big question mark.

One year before Pioneer 11 hit up the neighborhood, astronomers Stephen M. Larson and John W. Fountain suggested that two satellites were a better fit for the observation profile. Maybe Pioneer would settle it. Little did they know …

The danger 20,000 miles above Saturn’s clouds turned out not to be ring particles and small debris. Much closer to the intrepid space probe was Epimetheus, one of those two Larson-Fountain satellites. Closer than California and Cape Canaveral. Twenty-five hundred miles close, which, on Earth doesn’t seem all that close. But remember that Pioneer 11 traveled over a billion miles to miss a moon by so little. It’s like nailing a golf hole-in-one … from two or three miles away with a bank shot. But a fifty-mile wide satellite nearly wiped out the little Pioneer–they didn’t see it coming.

Voyager nailed down the two moons–Epimetheus indeed has a partner, Janus (imaged left, from Cassini). And they have an interesting relationship, despite not quite sharing the same orbit. They almost share an orbit. The inner satellite slowly gains on the outer, taking four years to catch up. Then something cool happens. The two moons switch orbits–as the inner one closes in on the outer, it moves to the outside, and the outer gets bumped closer to Saturn, thus starting another four-year chase. Lather, rinse, repeat.

Pioneer and Voyager opened our eyes to new satellites, close in to their father planets. Shepherd moons. Orbit-sharing. Crazy misses by a cosmic fraction. 1979 ushered in a new era of satellite imagination.

 

Astro Ramadan

I see that Muslims in France have adopted an astronomical start to Ramadan, rather than believe their eyes on that first crescent moon in the western sky.

Muslim scientists have been arguing for using astronomy to  determine Islamic dates for years, especially now that  globalized communications make it increasingly awkward for  different countries to start Ramadan on different days.

I wasn’t aware that this was a problem. Arabs were at the forefront of the science of astronomy through most of the European Medieval period. Many dozens of stars have Arabic names that predate their modern designation of Greek letter plus Latin constellation name.

I wonder what Muslims will do when they leave the Earth and travel to planets with more moons or none. Will the Earth calendar be followed from a distance? Will Muslim councils determine a different method from the lunar calendar?

 

Carnival of Space 293

They threw my book review into the 293rd Carnival of Space. The first 290 are linked here. Most of them, anyway.

 

On My Bookshelf: Understanding Variable Stars

As years pass, various interests wax and wane in astronomy. Some might says fads come and go. Early in the 20th century, there’s big interest for finding that second Earth–a blue and green planet somewhere in the universe where maybe aliens like us live. Our probes poke at Mars and try to tease out hints that life once existed there. Or maybe still does. And with a few recent hits and near misses, we look to stadium-sized rocks in our orbital neighborhood and wonder if our crash helmet will be enough next time.

John Percy’s book Understanding Variable Stars addresses none of today’s popular topics, really. He’s focused not on microbes, fossils, or skyfall, but on big game. Stars. And more, stars that change in brightness.

Why do stars change in brightness? It can happen when they are very young or very old. As it happens, stars pulse, blast, flare, flatten, sputter, spin, spill stuff onto other stars, eclipse, erupt, hide, reappear, degenerate, explode, and do all sorts of interesting things. Indeed, after I finished this book, I began to reflect that maybe our sun is the oddball. It just rises every morning and sets every evening and always comes up the same every day.

This is an advanced book for amateur astronomers. To get the most out of it, one will need a strong science background. Indeed, it reads like a textbook for an undergrad course in stellar astronomy. Lots of graphs. Lots of physics and some stellar chemistry. But an amateur with this book under her belt will be a force to be reckoned with in the world of AAVSO, the American Association of Variable Star Observers. And that means something because diligent amateurs, equipped with a good telescope, good viewing conditions, and a basic array of modern equipment, can make substantial contributions to stellar astronomy.

Let’s get back to that textbook thought. If this book is any indication of what it’s like to sit in one of Professor Percy’s classes, I would love to take Astro 261 Stellar Astronomy from the guy. He infuses just the right amount of history and personal interest. He communicates exuberance for his topic through text and data. Dr Percy loves astronomy, pure and simple.

Personally, I gravitate to the planetary regions of astronomy, but I borrowed this book from the university library just to broaden my horizons a bit. It’s good, especially for amateurs, to have a broad base of knowledge. I’m not sure why I needed to learn why the element lithium churns in the atmospheres of young stars and is barely found at all in the sun. But it was interesting to learn the up-to-date speculations about Eta Carinae. The first two chapters are as good an introduction to stars as I’ve seen anywhere. Chapter three sets the table for the topic in 32 pages. More than 200 pages breaks down most all types of variable stars as we know them–and this is the part where you really have to pay attention. I read this book in three weeks, and I certainly wouldn’t get top marks for the little I could recall.

I can’t imagine a better in-depth introduction to variable stars. If this branch of astronomy is your passion, this book needs a spot on your shelf. If you prefer galaxies, cosmology, or planets, it’s still a recommended read. How stars function and especially change will impact planets. What stars quadrillions of miles away from the Earth do is amazing. First, for how much information we can tease out of the universe just by watching it. Second, an appreciation that the sun is not a variable star. Third, for the implications of planet formation and eventually, I suppose, where the human race will settle after we leave the solar system. And then there’s just the wonder of it all. That last one’s enough for me.

The image is an infrared “movie” of Algol, a double star in which the components orbit almost edge on as seen from Earth. The dimmer of the two eclipses the brighter and even without a telescope, an observer can tell.

 

Carnival of Space 290

I used to contribute sporadically to blog carnivals. But they seemed to have disappeared mostly, at least from the Catholic bloggerhood. Or the hoods I visit regularly to occasionally. That would be an interesting phenomenon to study. But another day.

Enjoy the 290th Space Carnival, where I’ve made my first small carnival contribution in some time.

 

The Brightest Stars

I’ve been reading quite a bit in 2013, including some books on astronomy. In the next few weeks, I’ll take a look at some volumes currently on my bookshelf and assess them for readability by the general public, for amateur astronomers, and possibly, science pros.

I like a good book with information and that assumes some intelligence on the part of the reader. The Brightest Stars fits the bill. It’s accessible by a middle-schooler with a deep interest in astronomy, and contains some good bits for the seasoned adult skywatcher. Fred Schaaf is a long time amateur astronomer, multi-book author, and columnist for various magazines. He gives the reader one-third of the book with background on stars. He devotes the final two-thirds to twenty-one profiles of the brightest stars as seen from Earth.

My favorite part: tracking the movement of stars through the sky over hundreds of thousands of years. Did you know that 420,000 years ago, Earth had two very bright stars marking the north pole in the sky? The so-called fixed stars revolve around the center of the galaxy. But some stars aren’t following the same path as the sun. They “fly” into our neighborhood quickly and leave–all on the time scale of a million years or so.

Mr Schaaf includes personal anecdotes–good color. He gives both mythical lore and scientific history on our twenty-one stars. Also fascinating stuff. I appreciate the attempt to appeal to those with interest in science, history, and culture. He hits on all of that and held my attention.

My only quibble with the book is that it’s not well edited. Sometimes there’s too much repetitive information given, and it comes across as filler. Maybe editors leave veteran authors alone by their thirteenth book. Too bad. A good editor would have turned this B-plus book into an A.

 

Once-In-A-Century Fireball

Universe Today has amazing video footage from many sources of the meteor’s encounter with Russia. This might convince a few doubters it’s a very good idea to track as much space stuff as we possibly can.

 

Tau Ceti Musings: Interstellar Obsolescence

With the discovery of five planets orbiting the star Tau Ceti, does this mean all the sf literature on that system is now obsolete?

My take is that Asimov, Clarke, Niven, and others will eventually pass into the realm of Jules Verne and Edgar Rice Burroughs. These guys were skilled authors with great imaginations. Memorable characters, too. But eventually the factual truth about the universe–in this case other planetary systems–will come out. And we’ll be left to entertain ourselves by the quality of the writing. From the Universe Today site:

(T)his new discovery is the closest single sun-like star that we know of to host of an entire system of planets. The five planets are estimated to have masses between two and six times the mass of the Earth, making it the lowest-mass planetary system yet detected. The planet in the habitable zone of the star has a mass around five times that of Earth, making it the smallest planet found to be orbiting in the habitable zone of any Sun-like star.

I want to get to that “habitable zone” in a bit. But first, a thought that Tau Ceti may be more appealing than twentieth century guesswork in the books:

- As you can see above, when compared to the sun (left) Tau Ceti is bit smaller, less spotty, and more orange than our home star. If God decided to pull a cosmic switcheroo and give our solar system Tau Ceti one morning, we’d be deep in an ice age within a few years. Earthlike planets will need to huddle closer to that star.

- Tau Ceti is thought to be older than the sun. Generally speaking, astronomers think lower metal content in a star implies a formation farther back in time, before as many supernovae blasted as much iron, nickel, gold, etc. into the cosmos. One presumes that Tau Ceti’s planets will have less iron and rock, and more lighter elements and compounds: carbon, nitrogen, water, methane, ammonia, etc..

- Astronomers have detected about ten times as much “debris” around Tau Ceti. Amateurs are surprised to find out that it is easier for Earthlings to detect dust belts, gas clouds, and debris than it is to find planets. Ten times more asteroids, comets, and space dust swirl in Tau Ceti orbit. Given these new planets are so close in (inside the orbit of Mars in our system) I wonder if all the debris isn’t orbiting a bit farther out. I wonder if astronomers have fine tuned the location of all that junk.

- Astronomers have ruled out a Jupiter-sized planet, unless it’s way, way out from the other five. Jupiter is thought to protect Earth from too many comets and asteroids because it has swallowed up so many over the past billions of years. But on the other hand, without a Jupiter, Tau Ceti’s inner planets may be relatively safe from the occasional asteroid perturbed into an inner system visit.

Here’s why I’m a skeptic on habitable zones. Planets and moons can be warmed by things other than sunlight. Radioactive decay warms the Earth’s interior to the temperature of the sun. Tides of the moons of Jupiter keep rock molten and subsurface oceans liquid.

There is another reason that habitable planets are probably never going to be relevant for human travel in space, if we ever make it to the stars. It will take a ship thousands of years to travel the interstellar gulf. That ship will probably be the size of an asteroid or small moon, and will carry all the creature comforts of home. Even if Tau Ceti travellers were to find a nice planet on arrival, a large portion of the human occupants might prefer to stay on board ship. Why disembark to a planet with lots of unknowns?

 

Advent Lectionary: The Cosmology of Psalm 72

The psalm for Advent’s first Tuesday is the 72nd. It appears prominently on Epiphany, but we get a daytime preview of it on the third Mass of Advent. What do you make of the cosmology implied in verse 7?

Justice shall flower in his days,
and profound peace, till the moon be no more.

And here, in verse 17a?

May his name be blessed forever;
as long as the sun his name shall remain.

The likely end of the moon will be during the sun’s expansion into the red giant phase. The outer layers of the enlarged sun might slow down our massive satellite enough to spiral into the planet. Or expelled gas from the sun before that final stage might be enough to send the Earth spiraling out just enough to avoid the fate of collision and burning to a cinder.

Psalm 72 has had its interpreters focus on the Messianic aspects, otherwise the notion of a human king ruling till the end of the solar system seems an extreme exaggeration. We know, of course, that the reign of God will extend far beyond the end of the solar system. Planets will be swallowed up, or be ejected from the sun’s vicinity. The sun itself will swell up, then shrink to a white dwarf, and eventually cool to a dark ball of frozen carbon, neon, and oxygen. But grace and faith will remain, those tens of billions of years into the future, and beyond. The psalmist may not have had a glimpse into the ultimate future of the sun and moon, but his lyrical words are no less true.

 

On My Bookshelf: Martian Summer

I just finished Andrew Kessler’s Martian Summer: Robot Arms, Cowboy Spacemen, and My 90 Days with the Phoenix Mars Mission.

This book gives a peppy, irreverent, and informative inside view of the 2008 mission to the polar region of Mars. There are many books out there on space missions. Like those others, Mr Kessler’s book gives a wealth of science information as well as interpersonal exchanges between Phoenix scientists, engineers, journalists, and bureaucrats.

I found his narrative style a bit choppy. The book tends to get bogged down in small details–interesting details certainly, but not always connected to the big picture. The book reads like a series of blog posts. That’s not to say they’re not well-written; they certainly are. It’s just a different style of writing than what I’m accustomed to.

Recommended for Mars fanatics. Otherwise an interesting read, but not absolutely top-shelf.

 

Note The Moon’s Movements

Did you catch the full moon last night with Jupiter as a “punctuation mark” just above it? Over Iowa, the king of planets was almost washed out in the moonlight and hazy sky in the east last night.

Today’s Astronomy Picture of the Day shows the difference between “super” and “micro” full moons. Tonight’s nearly full moon will be slightly larger, but still very much smaller than the “super” of this past May. The moon’s orbit brings it about 2,000 miles closer tonight as compared to the same time last night. That difference will be very hard to detect without a reference point. Interesting to note that the “micro” moon travels more slowly in its orbit than the “super.” Any reference there is washed out by rotation of the Earth and the moon’s apparent movement through the sky. If you watched at different times last night through this morning, you would notice movement of the moon relative to the planet Jupiter.

In a dark sky, background stars will show this, with two observing times separated by a few hours. Winter affords younger children a chance to notice this. Go outside just after sunset and see if the moon is near a particular star or two. Then return just before bedtime and see if the position of our natural satellite has shifted. If the skies are clear the next night, you will see a big jump. But note: observe the moon at exactly the same time.

How much does the moon actually move against the background stars? That’s easy to figure out. 360 degrees make up a circle. The moon orbits the Earth in about a month. Divide and you get about twelve degrees a day. If you extend two fists side by side with straight arms, that’s almost 12 degrees.

If stars are hard to see in your city skies, you can also observe near moonrise or moonset. If, say, the moon is low in the east at 7pm tonight. Mark two fists toward the horizon and under your second hand will be about where the moon will appear at 7pm tomorrow night. Make sense? I hope so. One can also look up at the night slky. If you watch long enough, closely enough, you will see many subtle and beautiful things.

 

On My Bookshelf: Mirror Earth

For the past twenty years scientists have been finding planets outside the solar system. Michael Lemonick’s book is an excellent introduction to the science, as well as the story behind it: real people conducting extra-solar exploration.

It’s logical that astronomers find larger planets easier to detect. However, Jupiter-sized planets are not thought to be prime abodes for potential life in the universe. As detection methods improve, smaller and smaller worlds are found. The big hope is to find a place like Earth out there. Oxygen in the atmosphere. Water on the surface. Life getting by.

This book captures the effort to refine detection methods, to uncover new ones, and to move the search for life in the universe from the page of science fiction to telescopes and other tools and the application of human ingenuity to the challenges.

Finding that Earth-sized planet just the right distance from a star is the prize. (Not too close so as to be molten or have a steam atmosphere, and not too far away for a freeze-out.)

Mr Lemonick takes the reader through the excitement, planning, and expectations of the past two decades. The science is presented in such a way so as to be easily understandable to the casual reader. The human stories give added interest.

Spoiler: we haven’t found life off-planet yet. The effort continues. But this really good read gets you up-to-date as of early 2012.

 

No Craters on Methone, What’s Up?

No craters on this 3-mile moon of Saturn. What’s up with that? If this is a pile of ice rubble and dust, then why is it oblong? And maybe there are craters underneath a fluffy surface.

 

Give A Wink

I was thinking back to that summer night when I was ten, and had anticipated all evening the walk on the moon after the successful landing of the lunar module, Eagle.

I could not keep my eyes open for the whole moon walk; I fell asleep on the living room floor after about an hour. I was miffed that my mom didn’t wake me up. But her motto was that if your body’s telling you it needs sleep, then you should sleep. Besides, there will be other moonwalks. Not enough, in my opinion.

I didn’t react to the word of Neil Armstrong’s death as much as others. In another decade or two, no human will be left alive who walked on the surface of the nearest heavenly body. We all grow old. We all die. But young people can still dream, either in wakeful anticipation, or on a living room floor on far-off Planet Earth. From the Armstrong family statement:

For those who may ask what they can do to honor Neil, we have a simple request. Honor his example of service, accomplishment and modesty, and the next time you walk outside on a clear night and see the Moon smiling down at you, think of Neil Armstrong and give him a wink.