The Essential Dinosaur Pack Disc 2: DVD Review

This disc, although it has a copyright date of 2008, is a collection of TV programs originally aired between 2003 and 2008. Thus none are really up to date.

“The Mystery Dinosaur,” from 2006, deals with the discovery of  “Jane.” This fossil has been variously identified as a Nanotyrannus and a juvenile Tyrannosaurus Rex. The program is primarily about the argument, which could date it, but as far as I can tell, the argument has never been resolved. Thus the program is still fairly current, though it is more science than entertainment.

“Dinosaurs: Return to Life” deals with the observations that the differences between dinosaurs and birds appear to be due to a relatively small number of mutations. Could birds be “reverse bioengineered” to produce something like dinosaurs? Would we really want to?

The four-program series “Dinosaur Planet” first aired in 2003, and unlike the rest of the programs in this set, it is definitely intended to be entertainment. Each of the four episodes focuses on one or two individual dinosaurs and follows them through a period of their lives. Each episode also covers something that is important or intriguing in the fossil record, and links back to that record. Thus “White Tip’s Journey,” featuring a Velociraptor,  suggests one explanation for the famed (real) fossil of a Velociraptor locked in a death struggle with a Protoceratops.

“Alpha’s Egg,” featuring the large sauropod Saltasaurus and the medium-sized predator Aucasaurus,  is based on the discovery of  a Saltasaurus nesting ground,  fossilized in Patagonia.

Pod of “Pod’s Travels” is based on a Pyroraptor,  a European raptor genus. The episode includes the natural hazards (earthquake, tsunami) that made occasional travel between the islands that made up Europe 80 million years ago possible. The focus of the program is on the dwarfing effect that islands tend to have on species. Pod is a Gulliver among Lilliputians when a tidal wave sweeps him to a much smaller island.

“Little Das’ Hunt” follows a juvenile Daspletosaurus  (an earlier close relative of Tyrannosaurus Rex) learning to hunt, and a herd of Maiasaura. The episode is based on a group of Daspletosaurus and Maiasaura found fossilized together in Montana, but the evidence for the kind of pack behavior shown in the episode is scanty and controversial.

Obviously there is a good deal of imagination going into the behavior, color, feathers or lack of them, musculature and behavior of all of these dinosaurs. Here I want to mention three, because they struck me so strongly.

The first is the underline of the creatures portrayed.  Theropod dinosaurs did indeed have a bone jutting back from the pelvis. However, the velociraptors are shown as having this bone stick out of the body, covered by a narrow wedge of tissue. It seems to me that this arrangement would be very susceptible to breakage, and that evolution would have reduced the length of the bone fairly fast. It makes much more sense that the tail and the posterior part of the belly were much deeper, with the projection buried in muscle. In fact a mummified hadrosaur had exactly this conformation, with a tail much deeper than anyone expected. Why not Velociraptor?

Second is the behavior of prey dinosaurs. Granted they didn’t have much brain, but instinct is also guided by evolution. Threatening a predator with teeth adapted to munching relatively soft leaves, and exposing the vulnerable neck in the process, does not make sense. Kicking (recent work has shown sauropods had vicious kicks) or tail swipes are far more reasonable for the big plant-eaters. This bothered me as far back as the Disney dinosaurs in Fantasia, when the stegosaurus turns to try to threaten T. Rex with its tiny mouth, instead of lashing out with its spiked tail. Now Disney may be forgiven – after all, Fantasia came out in 1940. Between making his dinosaurs animatable by artists drawing each cel by hand and the paleontological knowledge of the day, he did a respectable job even if his sauropods did have necks like snakes and his characters never actually lived at the same time. But that stegosaurus is pure theater, and Discovery Channel should have known better.

The third is grass. There is now some controversy over whether dinosaurs and grass coexisted, but the amount of grass shown is almost certainly incorrect.

Overall evaluation? Watch, but don’t believe everything you see. This DVD has a lot of creative interpretation, some of it almost certainly wrong.

The Essential Dinosaur Pack Disc 1 (DVD Review)

This set of two DVDs, although the cover has a date of 2008, in fact combines episodes originally aired on the Discovery Channel from 2001 to 2008. The first disc contains four episodes:  Valley of the T. Rex (2001), T-Rex: New Science, New Beast (2006), When Dinosaurs Roamed America (2001) and Utah’s Dino Graveyard (2005). Keep the true dates straight, because our interpretation of dinosaurs is changing rapidly, and the episodes at times seem to contradict each other. None of the interpretations are truly currant, or represent today’s ongoing controversies.

This DVD focuses on the processes of finding, unearthing and interpreting fossils, with only minor clips of computer generation of the living animals. It will be of more interest to budding paleontologists than to those looking for entertainment.

Valley of the T-Rex looks at the idea put forward by Jack Horner that T-Rex was primarily a scavenger, not a predator. The idea is hardly new, and is far earlier than the discovery of T-Rex’s tiny arms – Wiley Ley proposed it as a science article in the April 1943 issue of Astounding Science Fiction. I really doubt that there is any such thing as a pure predator or a pure scavenger. Any predator will scavenge a fresh kill, and any scavenger will kill an animal down and helpless, if only by eating it. Like the short-faced bear, T-Rex may have used its impressive size to intimidate other predators off their kills, but that doesn’t mean it never killed.

T-Rex: New Science, New Beast is more balanced, mentioning that how T-Rex fed is controversial but not getting into the controversy. Rather, it summarized new (as of 2006) methods of investigating dinosaur fossils. This included learning how to tell how old fossil dinosaurs were at death (which led to the discovery of the fantastic teenaged growth spurt of T-Rex and the relatively young age (29) of Sue, the largest T-Rex found.) At least one dinosaur was sexed, though the technique only works with pregnant (with eggs) females. Study of locomotion in modern animals has been applied to dinosaur skeletons, suggesting a lower top speed for full-grown T-Rex than was previously estimated. The episode also mentioned the discovery that some fossil bone had collagen, study of T-Rex bite strength, and the discovery of feathered theropods, leading to the possibility that T-Rex juveniles, at least, had downy feathers.

When Dinosaurs Roamed America goes through the history of dinosaurs, using an American location to spotlight each time period. Remember this segment, and the computer animated clips included, is eleven years old in 2012.

The video starts with New York (Permian-Jurassic, first dinosaurs, early opening of the Atlantic.) It then moves on to Exeter Township, PA (Triassic-Jurassic boundary, theropod-sauropod split.) Utah was a savannah 150 million years ago, wandered over by giant sauropods, their predators, and the smaller herbivorous dinosaurs that survived at their side. New Mexico 90 million years ago was a tropical swamp, with an explosion of flowering plants and broadleafed trees. The notorious K-T (Cretaceous-Triassic) boundary and the final extinction of the dinosaurs is investigated in South Dakota. The video is not bad, but dated.

The final program, Utah’s Dino Graveyard, covers a single location with a huge number of dinosaur fossils of a single species. Falcarius Utahensis was a strange beast even by dinosaur standards, as are most of its Therizinosaurian relatives. It is one of the earliest of a group that evolved from raptor-like carnivores to big-bellied but still relatively upright herbivores. This does happen – all dinosaurs, even the huge sauropods such as Apatosaurus evolved from early ancestors that ran on two legs and preyed on insects. More recently, the giant panda seems to be a bear that has embraced a diet of bamboo.

The real question is, what killed large numbers of the same species? Their preservation seems to be due to the fact that they all died near ancient springs, with rock from the spring deposits forming a cap that preserved their bones, but could the spring also have played a role in their deaths?

In general the computer graphics are adequate but not inspired, and at times show behavior I have doubts about — but I’ll save that critique for the second disc.

Dinosaurs Inside and Out: DVD Review

This is actually a reissue of programs aired on the Discovery Channel in 1997, though the DVD has a 2009 date. The package date is very misleading, as both the facts given and the computer animation are 15 years old – before the first airing of Walking With Dinosaurs. The computer animation, in particular, is very poor, and I would certainly not buy this DVD to watch the dinosaurs!

The DVD includes four 1-hour programs: Renaissance of the Dinosaurs, Land of the Giants, The Killer Elite, and And Then There Were None. In order, they deal with the public fascination with dinosaurs, the large herbivores, the two-legged killers such as T-Rex and raptors, and the extinction of the dinosaurs.

Luckily, the program concentrates not on the videos, but on the science of paleontology. Even that is a bit dated in describing what is known about dinosaurs, though the finding, excavating, packing and cleaning of specimens is worth watching for budding paleontologists. So is the history of our fascination with dinosaurs, including more than the usual information about how our views about dinosaurs have changed since the Crystal Palace reconstruction and the dinosaur wars between Cope and Marsh.

If you are looking for a video to entertain children, this is not it. On the other hand, the DVD does have a number of airings of scientific controversies and field operations.

One point I would disagree with. The question of whether dinosaurs resembled birds or reptiles in care of young is addressed by using fossil bone cross sections to determine whether newly hatched dinosaurs had strong enough legs to stand. I strongly suspect that some dinosaurs could stand and some couldn’t, and the same is true of modern birds. Certainly chicks and ducklings are on their legs and finding their own food almost at once, and I suspect at least some dinosaurs may have been the same. I have seen arguments in later DVDs that some pterosaurs (which admittedly are not dinosaurs) were able to fly shortly after hatching.

All in all, this is not a DVD I would consider entertainment, but it could be of interest to a budding paleontologist.

IMAX T-Rex: DVD Review

Back when IMAX theaters were rare and found mostly in museums I went to a 3-D IMAX show – T-Rex – at the Smithsonian Natural History Museum. Even then I found it a peculiar amalgam of three-dimensional animation, paleontology, and not-very-good science fiction. (OK, it’s pretending to be science fiction, but it’s closer to bad fantasy.)

I got the DVD a while back, when I was getting most of the dinosaur videos available.

It’s a 1998 movie, and of course a lot has been learned about T-Rex in the intervening 14 years. Not enough, however, to make me feel like trying to pet one, or think it was capable of gratitude to another species!

Both the animation and the sequences of paleontologists in the field are fascinating, and so is the information about museum displays and Charles Knight. If the producers had stuck to the informational part, and perhaps used the idea of T-Rex as a nurturing mother in a more reasonable way, this could have been an excellent film, though a short one (44 minutes.) However, they insisted on adding a plot which involved something that left the audience guessing whether dreams, hallucinations, or time travel was involved. The supposed resolution, with a paleontologist finding a 20^th century watch, was totally ridiculous. Complex metal objects like watches simply do not fossilize.

Further, neither the big-screen of IMAX nor the 3-D were available in the DVD I have. This was a movie which depended on these effects.

Interestingly, there is considerable current research on the extent to which tyrannosaurs might have lived and hunted in family groups, and it is generally recognized today that birds are fundamentally modern dinosaurs, descended from the same bipedal group to which T-Rex belonged. The DVD, watched with the production date in mind, does give some interesting information on the history of how we think about dinosaurs. Just forget the plot!

p.s: As an update on last week’s post about ice jam floods, there is still a flood warning out for the Salcha River area, and the ice went out at Nenana at 7:39 yesterday evening. This can happen from April 20 to May 20, so breakup this year was early.

The Land of Painted Caves: Review

Jean Auel began her “Children of Earth” series over 30 years ago, with Clan of the Cave Bear. The Valley of Horses, The Mammoth Hunters, The Plains of Passage and The Shelters of Stone followed. Her latest addition, The Land of Painted Caves, continues to follow Ayla and Jondalar, still having difficulty communicating, and this time includes a tour of the cave paintings of France.

All are long books – The Land of Painted Caves is 828 pages in paperback and the others are about the same length. All are well researched. I discovered the series 30 years ago, primarily because of my interest in the Pleistocene and human evolution, and most of this review will be from that perspective.

From a writer’s point of view, the most recent book is full of information dumps, and rather weak on plot. That hasn’t stopped it from being a best seller, but there were times when I had to force myself to pick it up. I did manage to find a number of usable Twitter quotes, which are being posted and their contexts will be explained on February 29.

A good part of the book is description of the cave art of France. Auel does include a map keyed both to what the Zelandonii of her book called the caves and what archeologists call them, but I wanted to see some pictures of the cave art, not just descriptions. I actually searched the web for images from the caves, but found very few even when I knew the name of the cave. Good general references are http://myrencounter.blogspot.com/2011/07/land-of-painted-caves.html and http://www.donsmaps.com/indexauelfans.html, but they have more photos of the locations of the caves than of the actual paintings. White Hollow, identified as Lascaux, does have some images of the art at http://www.huffingtonpost.com/2010/09/12/inside-lascaux-the-versai_n_712645.html.

One possible source, at least for drawings of the cave art, is The Nature of Paleolithic Art, by Dale Guthrie. Dale is an artist himself, and while he suggests that a good deal of the “art” in the caves was equivalent to graffiti found in mens rooms, his first interest in cave art was as guides to reconstructing extinct animals. This is a huge book, with hundreds if not thousands of drawings of Pleistocene art from all over Eurasia, but putting the drawings in this book together with what Ayla saw would be a major project.

Leaving the art, there has long been a controversy in archaeology as to whether modern humans and Neanderthals (what Ayla calls the Clan) ever interbred, or whether such interbreeding was even possible. The argument went back and forth during the time period over which Auel’s books were being written. DNA for a time was used to claim such interbreeding never occurred. Then, less than a year ago, DNA evidence made it quite clear that such interbreeding had in fact happened. The basis of Auel’s books was if anything ahead of the archaeology of the time.

In one point, however, she was clearly wrong, though there was no way she could have known it at the time she started the series..  Jondalar and Ayla are described as being blonde and having blue and gray eyes respectively. Recent gene sequencing has strongly suggested that all blue and gray-eyed people are descended from a single common ancestor who lived between 6,000 and 10,000 years ago, well after the setting of Auel’s books. There is at least some argument that blonde hair may have evolved after the ice ages. Still, I cannot help but wonder if it could be derived from that Neanderthal admixture. If fair coloring is an adaptation to getting vitamin D in a region with little sunlight, such as Europe, the Neanderthals lived in Europe long before the Cro-Magnons arrived.

Bizarre Dinosaurs DVD Review #IAN1

All dinosaurs are bizarre, by mammalian standards. Some, however, are bizarre even to paleontologists, and the title program of this DVD is devoted to them. There is, however, a secondary program, not even mentioned on the cover, which to me was of considerably more interest.

Most of these animals are considered bizarre because they have appendages, preserved in the fossil record, that leave paleontologists wondering just why these animals have that appendage. Take the 33 foot-long Anargasaurus, for instance. Why on earth did this plant-eater have a double row of bony spines down its back? Reconstructions tend to show it with skin forming a double crest supported by those spines, but why? The only answer anyone had come up with is some kind of display crest, like the peacock’s tail.

Display organs are common, especially in today’s birds (which after all are modern dinosaurs) so I suppose it’s as good an explanation as any for such things as the plates of a Stegosaurus (which would have been potato chips to a large carnivore) or for the fanciful neck frills, often richly supplied with blood, of the Ceratopsids. Were horns used to fend off predators, of for fighting off rivals within the species? Or just for display?

In some cases the peculiarities might be associated with feeding. Take the Epidendrosaurus, for instance, a sparrow-sized dinosaur with an incredibly long third finger. Did it use its long finger as the aye-aye in Madagascar today does, to find insects in the bark of trees? Then there’s Nigersaurus, with a broad, flat head with a very wide muzzle resembling a vacuum-cleaner nozzle. Did it stand in one place and hoover up the vegetation?

This DVD is less interesting than most of the National Geographic programs scientifically, but it does show some interesting dinosaurs. If you want information on some of the animals shown, National Geographic has both an interactive site and a magazine article by John Updike.

The secondary program, which was a total surprise, should have been part of the Prehistoric Predators DVD I reviewed earlier. It was concerned with a much more recent animal, one I’d met before in Prehistoric Park—a predatory, flightless bird that could almost hold its own with sabertoothed cats and dire wolves. Certainly it seems to have taken down the same kind of prey.

These terror birds were not what you want to attract to your backyard bird feeder! Imagine an oversized ostrich with the hooked beak of a raptor, that beak (and head) enlarged to the size of a rather large war axe. With ostrich speed and taller than a man, they evolved to be the top predators on the South American continent, for many millions of years an island continent. Then a few million years ago, the isthmus of Panama joined it to North America, ending the isolation in which the terror birds had evolved. Animals crossed the new isthmus both ways. Opossums, armadillos, and porcupines moved north, but a far greater number of placental mammals moved south.

Surprisingly, a few terror birds did move north, as their fossils have been found in Florida. Did they meet with the earliest humans to colonize North America? Or were they simply unable to compete with the mega-predators already here? They did seem to survive for a long time in North America, but the jury is still out on just how long they lasted.

Tomorrow’s the day to look at quotes from Lewis Carroll, but I’ll also have a guest appearance on another blog, Christine’s Words. Stop by!

Sky Monsters (DVD Review)

No, they weren’t dinosaurs. True, model sets of extinct animals often include saber-tooth cats, sail-backs (which were mammal-like reptiles and more closely related to us than to dinosaurs) and extinct marine reptiles as well as pterosaurs, but none of these are actually dinosaurs. Pterosaurs did, however, live alongside dinosaurs and are of great interest as the largest animals ever to fly on their own.

This DVD, another of the National Geographic series, looks at the mystery of pterosaur flight. As usual, the animation is not very exciting, but the scientific work and the attempt to build a mechanical pterosaur more than makes up for that.

The big questions are, how large did pterosaurs grow and how did they fly?

One of the threads of the program is the rather controversial discoveries of trackways and fossils suggesting even larger pterosaurs than Quetzalcoatlus, which itself had a wingspan of 10 meters (33 feet.) That’s three times larger than an albatross, the largest flying bird alive today. Forget the giants; how did even the ones we’re reasonably sure of fly?

The meat of the DVD, as far as I was concerned, was an attempt to build a robotic pterosaur, controlled like a model airplane. The result was not wholly successful, but a great deal was demonstrated about pterosaurs in the process.

First, pterosaur wings were a good deal more complicated than the sailcloth that was first tried. They had oriented stiffening fibers, muscles within the wing membrane, a good blood supply to the wings, a furry covering that (like the dimples on a golf ball) helped aerodynamically, and some kind of built-in sunscreen. (Bats are nocturnal in part because their wings would sunburn too badly in daylight.)

Control was incredibly sophisticated, certainly more so than could be mimicked by a model airplane controller. Much of the maneuvering of a real pterosaur was probably as automatic as keeping your balance is to you – possibly more so, if the speculation that baby pterosaurs were born knowing how to fly is correct. Changing the shape of the wings and the tilt of the head would have been automatic for a real pterosaur. Not so for the model, and it is hardly surprising that it was not fully successful, even aside from the problems of finding components and power sources of sufficiently light weight. Pterosaurs, like birds, had very light bone structures.

As entertainment this DVD falls short. But as documentation of a fascinating experiment, it is worth watching.

Dinosaurs Unearthed: DVD Review

This is the first of a number of reviews of National Geographic’s DVDs on prehistoric animals, so I will start out by saying something that applies to all. They are very good in interviews with actual paleontologists. The computer graphics of the extinct animals are of moderate quality, and there are only a few clips repeated over and over again. These videos are excellent for budding paleontologists or those actually interested in the science of how we know about extinct animals, and are better than series like “Walking With Dinosaurs” in that they allow scientific arguments to be heard. They are not in the same league when it comes to the re-creation of the extinct animals.

This DVD contains two programs originally shown on the National Geographic channel: Dino Autopsy and Dino Death Trap. The first is about a rare fossilized mummy of a hadrosaur, nicknamed “Dakota,” found in the badlands of North Dakota. The fossil was found in 1999 by a teenaged paleontologist, and has supplied information on skin texture and musculature of hadrosaurs. The science is fascinating. The quality of the animation is somewhat less so.

The second program involves the excavation of a site in China. This site produced a number of near-complete skeletons from a period, the Late Jurassic, very poorly represented until now. Most of the attention is given to Guanlong, a very early form of tyrannosaurid. The skeletons are in three dimensions rather than flattened, which has been interpreted as evidence that they were trapped in soft sediments, and lie above each other in a vertical column.

There is speculation about how they died included in the video. Was a volcanic eruption to blame? Was the mud in which they were trapped due to volcanic ash falling into a marsh? Also, while these animals are the early forms of species known from the Cretaceous, the Cretaceous forms were giants, and these animals are relatively small. Guanlong’s back would about reach the waist on a standing human, yet it is an early relative of Tyrannosaurus Rex. What caused the increase in size? Did guanlong really have feathers as part of its crest? They are in the computer animation, and a relative, Dilong, is known to have had primitive feathers. The crest does appear to be a display organ (relatively thin and brittle) and feathers would have made it more conspicuous.

Overall the DVD is worth watching if you are really interested in dinosaurs. If you are looking primarily for entertainment, others are better.

Index of Science Posts

Here are links to all of the posts I would count as science, including those that explain how I use science in my science fiction. This list will be updated as new science posts are added. (Note that some posts listed under “Health” or “Technology” may also be of interest.)

The Science Behind Homecoming 4/2/10
Why do we have Weather? 4/24/10
Precession – Astronomy and Milankovitch 5/6/15
The Four Horsemen of the Apocalypse 6/12/10
Why Planets Have Seasons 6/24/10
Full of Sound and Fury (Fireworks) 7/3/10
Tricycles are not Bicycles 8/8/10
Planet Building 8/15/10 – 10/24/10
Racemization 9/2/10
Equinoxes and Daylight Savings 9/23/10
Horse Color Genetics 10/31/10 – 5/8/11
R’il’nai, Humans and Crossbreds: Life Span 12/11/10
Conservation Laws of Energy and Teleportation 12/20/10
Winter Solstice 12/22/10
Mass into Energy 12/24/11
Momentum and Teleportation 1/1/11
Snowflakes 1/7/11
Ice Fog: Ground Level Contrails 1/25/11
The Planets of Tourist Trap: Eversummer 3/6/11
Earthquakes, Tsunamis and Volcanoes 3/13/11
Why 12-Hour Days Already? 3/19/11
Ice Sculpture: Ice and Sun 3/26/11
More on Ice Melting 3/27/11
Why Temperatures Remembered Don’t Match the Record 4/5/11
When It’s Springtime in Alaska 4/8/11
Twilight 4/12/11
How High the Moon? 4/15/11
Breakup 4/16/11
The Cambrian Explosion 4/22/11
How Did We Learn to Walk? 4/29/11
Back to the Water 5/6/11
Where did the First Plants Come from? 5/13/11
The Geophysical Institute 5/15/11
Alaskan Mosquitoes 5/19/11
Colored-Leaf Geraniums 5/20/11
Early History of the Geophysical Institute 5/22/11
The Fairbanks Flood of 1967 5/29/11
Before Computers 6/5/11
Ice Ages and Alaska 6/17/11
Cumulus Clouds and Cloud Streets 6/24/11
Plate Tectonics Part I 7/1/11
Plate Tectonics Part II 7/8/11
Plate Tectonics Part III 8/5/11
Frost Hollows 8/19/11
Be Careful What You Ask For 8/27/11
Autumn Colors 9/10/11
Thermometers in Fairbanks 9/17/11
Junk Mail and Plants 9/20/11
The Chimney Sweep 9/22/11
Lights, Batteries, Temperatures? 9/24/11
How Dry I Am 10/15/11
Keeping Windows Dry 10/22/11
Snowflakes 10/29/11
The Alaskan Mesozoic 11/1/11
Mesozoic Alaska Part 2 8/11/11
Alaskan Mesozoic 3 11/15/11
Death of Blue Babe 11/17/11
Nightlength Sensitivity in Houseplants 12/10/11
Our Sense of Smell 12/17/11
What Time of Day is Warmest? 12/31/11
Alaska Winter Weather: Cordova and Nome 1/14/12
Inversions and Smokestacks 1/28/12
January Wasn’t Warm in Alaska 2/4/12
Fog, Fog, Fog 2/11/12
Oceanography DVD Review 2/14/12
Snow Festoons 2/18/12
Disturbance Hardening of Snow 3/24/12
Cold-Packed Snow and White Ice 3/31/12
Tornadoes and Climate Change 4/7/12
Breakup Season 4/14/12
Ice Jam Floods 4/21/12
Calories and Weight 5/5/12
Battery Woes 5/12/12

Why an Index?

With 550 posts as of today, I’ve started to have problems remembering what I’ve already put on here. This is particularly a problem with posting existing content such as poems, short pieces from the Summer Arts Festival, or science explanations originally written for the Alaska Science Forum. I can’t remember which books or DVDs I’ve posted reviews on. It also is starting to be a problem when I want to link to a previous post and can’t remember when it was put up or what the title was. And there are posts on this blog that have permanent information, like the series on planet building and the one on horse color genetics, or the book and DVD reviews. I want to make it easier for my readers as well as myself to find things.

I made a start some time ago by adding an index page, which can be accessed from the menu at the top of any page. Right now, the only links are to index pages on my author site. This takes you out of the site and sometimes back in, which is rather clumsy. The index list is also incomplete.

I’m going to start posting an occasional entry which is strictly an index of past posts on a particular topic. These posts will be linked from the index page, and will link forward to the individual blog posts. As it takes a while to find all the posts that belong together, this will be a slow process—probably extending over the next few months. The first in this series, on DVD reviews, is already queued for January 3. Others will follow, most on Thursdays.

I probably won’t be indexing every post. Some, like those early posts which were simply glossary entries for my books, are on the author site and really belong there. Others, like the regular Monday updates on North Pole weather starting in November 2010, can be found easily enough just by using the calendar on the site. But I hope that by the time I have finished this, older posts of interest will be easier to find.