Monday, November 23, 2015

Throckmorton on Homo naledi

On Saturday, November 21, I had the privilege of hearing Zach Throckmorton of Lincoln Memorial University speak on Homo naledi at the Gray Fossil Site just outside of Johnson City, TN.  Dr. Throckmorton is an expert on feet, and he was part of the research team that studied the fossils of Homo naledi after they were excavated from the Rising Star Cave.  My regular readers know how excited I've been about the discovery of H. naledi in the Rising Star Cave in South Africa, and so it was an easy decision to go hear Dr. Throckmorton at one of Tennessee's most intriguing fossil museums (seriously, you should check it out).

His talk was a pretty straightforward recounting of the discovery and description of the Rising Star fossils.  If you've been following the news at all, then you probably know all the details, so I won't recount them here.  He confirmed that the shoulder, arm, and hands all appear to be adapted to tree-climbing, and he indicated that the foot was extremely human-like.  According to his story, he got a little nervous when he first saw the photos of H. naledi's foot, because he thought it was modern human (then he looked at the rest of the pictures and knew that it was not modern human).  He also emphasized that the bones were free from disease and disorder.  Not even a cavity.  Other than some mild arthritis, these creatures lived a pretty healthy life.

I was quite struck by his candid discussion of the burial of these creatures.  He was careful to note that they preferred the burial hypothesis because they could not find another credible explanation for why the bones would be in that remote chamber.  At the same time, he admitted that these hominins not only buried their dead but also must have used fire to get that far into the cave.  There is no direct evidence of fire use, but how else could they see to get the bodies into that chamber?  He noted that even in modern caves where we know that people have used fire, ash and accidental scorch marks are generally absent.

What will the future bring?  Dating and DNA of course.  Dr. Throckmorton was not optimistic about the DNA, though, but it's worth a try.  He alluded to the "controversy" consisting of some rather nasty accusations that have been stoked by the press, but he remained enthusiastic that they were doing paleoanthropology "right."  I couldn't agree more.  My favorite slide from his talk:

Those of you still wondering what I think will have to keep wondering for a few more months.  There is still a lot of work to do, and I'm still not inclined to spill the beans too soon.  I did want to mention that Joel Duff's blog "Naturalis Historia" has a little score card of Homo naledi opinions from ICR, CMI, and AIG if you're interested in such things.

That's all for now.  Dr. Throckmorton's talk was very interesting (I learned a lot about anatomy too), and I'm grateful to the Gray Fossil Site for hosting him.

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.

Thursday, November 5, 2015

Homo naledi coming soon

I just finished (sort of) the first draft of my paper on Homo naledi, and it's a whopper.  I sort of just stopped working on it for now, because it's already too long.  Like most research, new data led in new directions and caused me to reconsider some things I had thought before.  The results of my analysis are really provocative (even to me), and I'm really stoked to get this paper published.

Next, it goes out for private review from colleagues, then it will undergo peer review at the Journal of Creation Theology and Science.  God willing, it will be published in a special issue on human origins early next spring along with a few other papers on human origins.  I hope you're looking forward to it.  I know I am!

I really want to say more about this discovery, especially since several other creationists have already chimed in.  But... I think it's better if I wait for the paper to come out.

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.

Tuesday, September 29, 2015

How about that water on Mars?

NASA announced a big press conference over the weekend about the planet Mars, and I took time out of Algebra II yesterday to watch it with my students.  As most people expected, they announced evidence of liquid water on Mars.  So what's the big deal?

For some time now, scientists have observed seasonal streaking on slopes on Mars.  You can see some of the streaks in the image above (courtesy NASA/JPL/University of Arizona).  They've been called RSL, which stands for Recurring Slope Lineae, which means, "lines that appear repeatedly on slopes."  That certainly seems like the action of some kind of liquid running down the slope making the surface appear darker.

But wait, Mars is farther from the sun that we are, about 48 million miles farther than earth on average.  That makes Mars much colder than earth.  According to, the average temperature on Mars is -80 degrees F.  During the summer, some spots on the equator can get up to 70 degrees F, but at night the temperature can still drop to 100 below.  How could there be liquid water under those circumstances?  Wouldn't the water be frozen, except for those brief warm days on the equator?

Well, if you remember back to your general chemistry days (if you took general chemistry), you might recall a thing called "freezing point depression."  When you add salt to water, the freezing point goes down (and the boiling point goes up).  That means you can have liquid water at temperatures colder than the normal freezing point of water.  Is that what's happening on Mars?

NASA scientists and collaborators pointed an orbital spectrophotometer at the RSLs.  A spectrophotometer is an instrument that can detect the presence of all sorts of chemicals, and the one they used is on a satellite orbiting Mars.  When they measured the RSLs directly, they found evidence of salt water, but when the RSLs were gone (during the Martian winter), there was no evidence of salt water.  The salt they found was a chemical called perchlorate, which apparently can lower the freezing point of water quite a bit.

So there you have it, folks, liquid water on Mars.  What does it matter?  Well, you'll notice in the press release that they make a big deal about life on Mars, which has an interesting connection to origins.  Here's how the reasoning goes: If you think that there is a natural explanation of where life came from in the first place, then you will not be satisfied with explaining life by claiming that God created it.  Instead, you'll want to figure out how it could have happened, whether or not God was involved.  But you also notice that life is amazing and complex, and it seems unlikely that it would just happen.  This leads you to suspect that life "emerges" (whatever that entails) when the conditions are right.  So if you can find life on Mars, that makes the second option seem more credible.  Finding life on Mars would make life on earth seem less spectacular and unique and more of a natural consequence of having a particular sort of planetary system.

Liquid water factors into this because liquid water is required for life as we know it.  Finding water on Mars makes it at least plausible that life of some sort could exist there, although perchlorate brine is not something I would think of as favorable to life.  Let's be very careful about this hype though:  Finding liquid water on Mars does not change the probability that we will find Martian life.  Liquid water makes it more plausible or possible that life could exist there, but plausibility does not mean probability.  All kinds of crazy things are possible, but that doesn't make them likely.

As for me, I think water on Mars is neat, and if there were genuine Martian microbes, that would be neat too.  Since I already know that God created life, discovering life on Mars wouldn't really change anything I believe about origins.

Ojha et al. 2015. Spectral evidence for hydrated salts in recurring slope lineae on Mars. Nature Geoscience doi:10.1038/ngeo2546.

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.

Tuesday, September 22, 2015

Figuring out Homo naledi

Homo naledi has been a delightful development in my life, and I had nothing to do with the actual research.  I just got up one morning and found two emails from some very early risers who had already read the press coverage.  That derailed my whole day's work as I concentrated on better understanding what exactly Homo naledi was and what it might mean for my understanding of creation.  Few things get me more wound up than new hominin fossils.

As you might expect, though, there have been some folks happy to use Homo naledi as yet another opportunity to mock creationists.  It's tiresome, but it comes with the territory.  Apparently, because creationists disagree about the significance of Homo naledi (and specifically about whether or not it's human), we're stupid, anti-scientists, clueless, whatever.  Of course, I could reverse that opinion, since there's not a lot of agreement on just what Homo naledi means for human evolution.  What's good for the goose is good for the gander, but that really would be stupid to claim that people are stupid just because they don't agree about something.

Normally, I don't like to pay much attention to insults, but the story going around is that I don't know what Homo naledi is.  Specifically, my hesitance to speak publicly and declare Homo naledi an ape (or a human) has been interpreted as uncertainty.  I want to publicly clarify that I'm not uncertain at all.  Actually, since the first day I heard about Homo naledi, I've been quite confident about what H. naledi is, and I'm mighty tempted to put my opinion right here and take my stand with the other creationists who have declared their opinions.

But the reality is that there are larger issues here.  Many of my readers know that the "historical Adam" has become a debate in evangelical Christianity.  There are some scholars calling us to abandon traditional belief in a real Adam and Eve and instead adjust our theology to do without such characters.  As you might imagine, I don't agree with such things, but I think that the question of the historical Adam is just a superficial issue on top of much bigger problems.  Questions about worldview, science and faith, and evolution in general form an important context within which we pursue answers to questions about the historical Adam and Homo naledi.  To strip questions like "Was Adam a real person?" or "Is Homo naledi just an ape?" out of the larger context is to do a great injustice to scholarship as a whole.  The average churchgoer just wants easy answers, but the reality is that easy answers aren't very easy to come by.  Answering questions about Adam and Homo naledi takes a lot of effort, and what you think about those answers will depend greatly on other questions that might seem unrelated until you start digging into the issues.

So I've got bigger fish to fry here.  I'm not interested in giving some knee-jerk response to naledi.  I'd much rather consider and re-consider my own conviction about naledi.  I want to consult others who know more about subjects that I don't (like geology and theology).  I want to consider other sorts of data than the type I usually focus on.  Unfortunately, that means I don't get to share what I think right away, but that's an important lesson.  We as a church need to become more comfortable with the discomfort of not knowing things right away.  Answers are not easy, and we need to understand that.

If Homo naledi can help teach us patience and longsuffering, then God bless Homo naledi.

(Photo is courtesy University of Witwatersrand)

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.

Wednesday, September 16, 2015

Dawn of Humanity or Dawn of Recovery?

Tonight on PBS, you can watch the latest NOVA/National Geographic co-production, Dawn of Humanity, focusing primarily on the Homo naledi discovery.  Or you can visit the NOVA website to stream it right now, or you can get it on Amazon and stream it there.

I just wanted to share a few thoughts about the special, because the film stirred up all sorts of excitement in me (again).  First of all, a disclaimer is in order: this movie is thoroughly, unabashedly evolutionary.  I know that should go without saying, but I continue to be surprised by folks who are surprised by how conventional science is so thoroughly evolutionary.  Newsflash: These fossils are interpreted in terms of human evolution on this program.  Human evolution means ape-like creatures evolving into human-like creatures.  Don't expect anything better than that.

Second, this film really communicates the thrill of discovery.  Key points in the discovery and excavation were filmed from the beginning.  We get to see footage of the first two guys going into the cave and finding the bones.  We get to see fossils being unwrapped and declared, "It's Homo!"  We even see the tears of joy in the eyes of one of the young scientists as she watches these discoveries unfolding right in front of her.  Even though I don't think they're right about their evolutionary conclusions, I can relate to the thrill they feel.

Third, we get a look at a body reconstruction of Homo naledi, and they look really weird.  Here is a still from the special that I grabbed.  It's copyright NOVA/National Geographic and whatever researcher made it (and if some official person wants me to take it down, say the word, and it's gone).

On first glance, it's the limb proportions that jump out at me.  Those gangly arms hang all the way down to the knees!  What kind of a creature was this?

Now if you're a young-age creationist, you might be wondering what to make of all this.  The best I can tell you right now is to think of this as something that lived after the Flood, in the wreckage of a world struggling to recover from the worst disaster in history.  Life was not easy for these creatures that God made, whatever they were.

Creationists also might like to read about other creationist reactions.  AIG's Elizabeth Mitchell downplays the evidence of burial and argues that the fossils are not human.  Paleontologist Kurt Wise thinks otherwise, as he shares in this World magazine article.  In the same article, old earth creationist Fuz Rana of Reasons to Believe sides with Mitchell and claims H. naledi is not human (no surprise there).  ICR's Frank Sherwin cautiously suggests it might be human (UPDATE: Someone at ICR has updated the page with a cryptic bit about primate characteristics and shortcomings of the burial interpretation, and it's not clear if Sherwin would continue to stand behind his initial impression).  Ken Ham wisely notes that creationists will likely disagree on Homo naledi because of the fragmentary nature of the fossils and our limited ability to examine the fossils firsthand.

However this turns out, I would like to publicly thank God for putting me here at this point in history.  Within three months, I've seen high resolution images of the surface of Pluto and now Homo naledi.  As a kid growing up in the 80s, I could only imagine such wonders, and God gave me life and eyes to see them!

How great thou art!

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.