Category Archives: Space

On this day…

July 21, 1969, Neil Armstrong and Edwin “Buzz” Aldrin Jr. became the first human beings to walk on the surface of another world. Forty-two years later, on July 21, 2011, the last operational space shuttle ended it’s final mission. As of today, NASA no longer has any in-house manned spaceflight capability, and will be relying on the Russian Soyuz vehicle to send crews to the ISS until the SpaceX Dragon (which will remain privately owned) enters service.

 

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Last roll out

Over at the NASA web site there is a wonderful picture of a very sad event – Atlantis being moved to the pad for the last launch ever of a space shuttle. I call this event sad rather than bittersweet only because there is no replacement vehicle. I can’t deny that the shuttle needs to be retired; it has served honorably, for far longer than anybody had a right to expect. It really should have been taken out of service twenty years ago. But twenty years ago, NASA didn’t have anything to use in its place. Sadly, they still don’t.

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Solar weather forecast: calm

As reported by Space.com, three separate studies suggest that our sun is entering a less active phase. We may be seeing significantly fewer sunspots for the next several decades. That could be very good news for space exploration, as a less active sun means fewer flares or solar storms, which can damage electronics and endanger astronauts.

On the other hand, periods of reduced solar activity have historically also been periods of significantly cooler weather, although I understand that the reasons for that are not well understood.

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Did a solar flare cause the Pleistocene megafauna extinction?

That’s the theory advanced by physicist named Paul A. LaViolette. I was quite intrigued when I first saw the news story about LaViolette’s proposal. Happily, the story included a download link to a preprint of the paper (which was published in Radiocarbon). My evaluation, therefore, can be based on the paper itself and not just the summation given in the story.

I’ll admit I had some reservations right from the beginning, when I saw mention in the story that LaViolette had written a book in 1997 arguing that certain themes found in mythologies worldwide are references to intense solar activity at the end of the Pleistocene. I’m not an expert in solar physics, but I do know something about oral traditions. If the book is what the story claims, then LaViolette makes the same mistake that Von Daniken and Velikovsky made: treating myth as a distortion of history, which it is not. Mythology is not bad history, or mistaken history, because it’s not history at all, but something very different. This is a peripheral issue, however, as there is no mention of any oral traditions in this particular paper.

Although, as I said, I am not an expert in solar physics, I do have enough of a physics and chemistry background to follow LaViolette’s argument. Basically, he uses evidence from isotope analysis of seafloor layers called varves from the Cariaco Basin (off the coast of Venezuela) to argue for a massive solar flare between 12,957 and 12,760 years ago. This would be near the beginning of a period of rapid global cooling called the Younger Dryas. In addition to the Cariaco varves, LaViolette also uses data from Greenland ice cores to bolster his argument.

LaViolette goes on to argue that the magnitude of this flare – he estimates it as about 125 times more powerful than a similar type of flare observed in 1956 – would have overpowered the Earth’s magnetic field and allowed animals at ground level to receive at least 3 sieverts of radiation, in the form of high energy protons, which would be close to a lethal dose. He bases this on the presumption that the flare would have lasted about 50 hours, similar in length to the 1859 Carrington Event, and he takes into account the shielding effect of the atmosphere. He also suggests that the partial collapse of the magnetic field due to the flare would have allowed some of the interplanetary dust  that surrounds the planet to fall to earth, and argues that this explains the extraterrestrial dust markers that have been found in some sediment cores.

I’m not qualified to evaluate whether or not a solar flare is the best explanation for LaViolette’s isotope data; he may very well be right about that. I was surprised to notice, however, that his estimate of the radiation dosage assumes that the animals on the ground were exposed for the entire 50 hours, even though the sun would have been on the opposite side of the planet for roughly half of this period. Also, the amount of atmosphere through which the protons would have to pass would logically depend upon the angle of the sun in the sky, which obviously varies throughout the day.

A second problem is that LaViolette nowhere addresses the geographically uneven nature of the terminal Pleistocene extinctions. While a large majority of North American species larger than 100 kg went extinct, very few African or South Asian species did. Extinction rates on the other continents lie between those two extremes. It is certainly conceivable that some mechanism might exist that could cause a solar flare to produce this effect. However it is not immediately obvious what that mechanism might be. Some discussion of this problem, I believe, ought to have been included.

Of course, the question of whether the Pleistocene extinctions occurred very rapidly or over a period of several thousand years is far from settled. However, this is not necessarily a problem for LaViolette’s hypothesis. It is easily conceivable that a short burst of intense radiation could eliminate or severely reduce the populations of a few keystone species and thereby have a long term destabilizing effect on an entire ecosystem. If this were the case, identifying those keystone species and showing that they were, in fact, the first to become extinct, would be a primary step in building a chain of supporting evidence.

Although, as I said at the beginning, this is an intriguing idea, as presented it has some significant problems. Until those are addressed, I believe a skeptical approach to LaViolette’s model is warranted.

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Visiting the asteroid belt

While most of the world’s attention has been occupied with other matters, a spaceship with an advanced ion propulsion system has been quietly approaching Vesta, the second largest object in the asteroid belt. Launched in 2007, the spacecraft named Dawn is scheduled to arrive at Vesta in July of this year. After orbiting Vesta for a year, Dawn will move on to the dwarf planet Ceres in order to investigate that body as well. If it works, it will be the first time a space probe has ever entered orbit around one world, and then left it to visit another. All previous multi-body space missions have been quick flybys.

Yesterday Dawn began to navigate by tracking Vesta with its own camera; prior to that it had relied on radio signals from Earth. Space.com has the story, complete with pictures of both Vesta and Dawn.

What makes this seem rather weird to me is that I can still remember the original Star Trek episode Spock’s Brain, in which Scotty stated that ion propulsion was significantly more advanced than the antimatter-powered warp engines the Enterprise used.

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The Big Boy can do what???

The Union Pacific Class 4000 Big Boy is widely considered to be the most powerful class of steam locomotive ever built. Starting in 1941, 25 Big Boys were built for the Union Pacific Railroad by the American Locomotive Co. in Schenectady, New York. The Big Boys were articulated, meaning they could bend in the middle to go around curves, and had two sets of driving wheels, with eight drivers (four pairs) per set. Four smaller wheels made up the pilot truck in the front, to help ease the huge locomotive around curves. A trailing truck at the rear had another four wheels to carry the weight of the firebox. This gave the Big Boy a wheel arrangement of 4-8-8-4*.

The Big Boys were designed to pull heavy freight trains over the Wasatch Mountains. Prior to their delivery, long trains needed extra helper locomotives to get over the mountains. This meant delays while the helpers were put on and taken off, as well as paying for extra crews to operate them. Using Big Boys, each capable of pulling more than 4,400 tons up the 1.55% grade, resulted in significant savings of time and money.

Technology marches on, however, and even the most powerful steam locomotives in the world could not stay in service forever. The Big Boy’s last run came in 1959. The diesels that replaced them were individually far less powerful, but could be connected such that multiple units were all operated by a single crew. Today eight Big Boys still survive in museums, although none of them are in operating condition.

One thing about the Big Boy locomotives that I did not know until recently is that they can also operate in outer space, at least according to this anime. Yep, that’s right. Trains traveling through space, pulled by steam locomotives. Complete with steam whistle, and a big plume of smoke (The Big Boy first appears at around 2:10. If you freeze it at 2:18, the overhead view clearly shows coal in the tender.). And on top of everything else, this English language version of a Japanese cartoon also features space panzergrenadiers.

Every time I think that anime just can’t get any stranger…

 

* Steam locomotives are classified by wheel arrangement, read in order from front to rear.

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Space archaeology

I recently stumbled across an interesting discussion on Steve Wilson’s blog, of the various definitions of space archaeology (in two parts, here and here). The focus is mostly on three intersecting subcategories of space archaeology: aerospace archaeology – the archaeological study of flight and space exploration, exoarchaeology – investigation of archaeological sites located off the Earth, and xenoarchaeology – the archaeological study of past non-human cultures. (He illustrates the overlapping nature of these three sub-fields with this chart.)

Xenoarchaeology, arguably the most interesting of the three, is obviously purely speculative at the moment, as no confirmed evidence of non-human cultural activity has yet been found. (The study of stone tools and other artifacts manufactured by hominids other than Homo sapiens could presumably be considered xenoarchaeology, but in practice the term is not used in that way.)

Of course, the lack of any actual evidence has not kept vast numbers of trees from being killed to promote wild theories involving alien visitors, both ancient and modern. As far as I’m aware, William Doleman’s excavation at the putative UFO crash site near Roswell, New Mexico remains the only legitimate xenoarchaeological field investigation. A few very speculative papers have appeared (usually using the term SETA: Search for Extraterrestrial Artifacts), but I am not aware of any that have been authored by archaeologists.

However, the other two sub-fields, aerospace archaeology and exoarchaeology, have become mainstream enough to be discussed in a space archaeology symposium at the recent SAA conference. The focus of the symposium was on the preservation of our aerospace cultural heritage, rather than investigating aerospace sites, which is perfectly understandable. Most of the questions that space archaeologists could address involve unique events (i.e., why and how did a particular space vehicle malfunction), rather than the patterned cultural behavior that is more properly the subject of archaeological investigation. In addition, on site investigation of archaeological remains located off Earth is likely to remain prohibitively expensive for the foreseeable future.

Investigation of exoarchaeological sites using remote sensing* is a more practical approach, and some types of projects have already been carried out. (Phil Stooke’s tracing of the path of the Lunokhod 2 rover last March being one example.) More ambitious projects may be able to piggyback on future space missions. If a sufficiently compelling research question can be devised, it might even be possible to fund a space mission specifically for an archaeological purpose (although the current state of the economy makes that appear unlikely in the near term).

As I stated, aerospace heritage preservation was the primary focus of the speakers at the SAA conference. This mainly involves legal and political action right here on Earth, and significant work can be done at a much lower cost than even the cheapest space mission. It is also somewhat urgent, given the potential that space tourism and other private space ventures have to damage irreplaceable heritage sites.

Presently, NASA’s concept of space archaeology is largely limited to the use of satellite remote sensing to study archaeological sites on Earth. This is itself a fascinating and important subject, but I hope that within the next few years they will also develop an interest in some of the other aspects of archaeology in, or involving, outer space.

 

* Please don’t confuse remote sensing with the paranormal practice of remote viewing.

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Ancient skywatchers

According to a paper recently published by an archaeologist in the U.K. the Panathenaic Games, one of the most important festivals in ancient Greece, was timed to begin just when the constellation Draco appeared in the evening sky. Unreported Heritage News has the story.

One of the things I love most about archaeology is the incredible diversity of skills used: physics, geology, architecture, animal butchering, and just about anything else. In this case, Dr. Boutsikas needed a knowledge of both astronomy and mythology to figure out not just what the citizen of Athens were seeing in the night sky, but why it was important to them.

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SAA day three

I just realized that I’ve been blogging about the SAA conference without mentioning that SAA stands for the Society for American Archaeology.

Today was the last full day of the conference. One of the highlights was the symposium on the preservation of space-related heritage sites. With interest in space tourism increasing, it’s only a matter of time before some yahoo wants to put their footprints next to Neil Armstrong’s. Several of the presenters have been working at getting some of the most historically important locations, such as Tranquility Base, listed as world heritage sites. This would make it easier to protect them from being damaged or destroyed. Catherine (my wife) is as interested in space exploration as I am, so she came down to the convention center to sit in on this one too.

Beth O’Leary, the first presenter, has co-edited the Handbook of Space Engineering, Archaeology, and Heritage, which I picked up yesterday. It runs nearly 1,000 pages, and looks like it covers the technological, cultural, and legal aspects of space archaeology. So far I’ve only leafed through it, but I’m expecting to enjoy it immensely.

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Welcome home Discovery!

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