Exposing PseudoAstronomy

April 23, 2015

How Do We Know How Old Stuff Is on the Moon?


Introduction

While this movie is branded under “Exposing PseudoAstronomy” for legal reasons, it has less to do with popular misconceptions/conspiracies/hoaxes and more to do with real science. This is my third more modern, lots of CGI movie, and my second to explain a research paper that I wrote.

In the movie, I go through how the lunar crater chronology is the fundamental basis for how we estimate the ages of surface events across the solar system. I also explain how my work affects the lunar crater chronology and what can be done to better constrain it.

I’m still waiting for a young-Earth creationist to claim that because of a factor of 2 uncertainty, 4.5 billion becomes 6.019 thousand.

I also wrote a blog post about this for The Planetary Society. Because it was posted there over two weeks ago, I think it’s fair game to repost here. You can click on any of the images for larger versions, and all of them are screenshots from the YouTube movie.

Planetary Society Blog Post

Three years ago, I started a project to replicate work done by various groups in the 1970s and 1980s. When the project was completed, the result implied that much of what we think we know about when events happened in the solar system were wrong, needing to be shifted by up to 1 billion years. I presented this in a talk at the recent Lunar and Planetary Science Conference at 8:30 AM, when most people were learning about the latest results from Ceres.

The project started simply enough: I downloaded some of the amazing images taken by NASA’s Lunar Reconnaissance Orbiter’s Wide-Angle Camera (WAC) that showed the Apollo and Luna landing sites. Then, I identified and measured the craters (my dissertation work included creating a massive global crater database of Mars, numbering about 640,000 craters).

The reason to do this is that craters are the only proxy we have for ages on solid surfaces in the solar system. We can determine the relative age of one surface to another (is it older or younger?) by looking at which has more craters: The surface with more craters will be older because, when you assume that craters will form randomly across the body, then the surface with more craters has had more time to accumulate them.

How to Use Craters to Understand Ages

Basic principle behind this work. (Background image © NASA/ASU; composite © S.J. Robbins.)

If we want to use craters for an absolute timeline – as in, actually put numbers on it – then we need some way to tie it to real ages. This was made possible only by the United States’ Apollo and the USSR’s Luna missions that returned rocks from the moon that could be radiometrically dated in labs on Earth.

With these radiometric ages, we then identify the craters on the surface those rocks were gathered and say that a surface with that many craters per unit area is that old.

That’s the lunar crater chronology: The spatial density of craters larger than a standard size versus radiometric age (we use 1 km as that standard size). This crater chronology is then scaled and used as a basis for the chronology across the rest of the solar system. When you hear someone say that something on the surface of Mars is X number of years old, chances are that’s based on the lunar samples from the 1960s and 70s and the crater counting done 40 years ago.

Apollo 15 Landing Site

Example landing site area, Apollo 15 (yellow star). Blue outlined areas indicate regions on which craters were identified, blue shaded areas were removed because they are a different type of impact crater, and blue circles are the craters mapped and measured. (Background image © NASA/ASU; data and composite © S.J. Robbins.)

And, that’s where my project came in. While the rock samples have continued to be analyzed over the decades, the craters were not. It’s easy to assume that the researchers back then did a great job, but by the same token, science is about replication and re-testing and we have developed new ways of doing things in the crater community since the Apollo era. A simple example is that the crater chronology requires a spatial density, and therefore you need to know the area of the surface on which you have identified craters. Over the past 40 years, we have better understood the shape of the moon and now have computers to allow for much more precise area calculations. This can result in changes by 10s of percent in some cases.

When I had finished my reanalysis, my results differed for many of the landing sites, in some cases by a factor of 2 from what the standard is in the field. I was surprised. I checked my work and couldn’t find any mistakes. So, I combed through the literature and looked to see what other people had published. I ended up finding a range of values, and only in one case was my result at the extreme low or high of all the published results. I showed my work to colleagues and none of them could find any issue with it. So, eventually I published it, early last year.

The Lunar Crater Chronologies

The new (blue) and old (red) chronologies and the data used to fit the model. The vertical axis shows the spatial density of impact craters larger than or equal to 1 km in diameter, and the horizontal axis shows the age of the surface from radiometric dating of collected rock samples. (© S.J. Robbins)

When I fit my crater data to the radiometric ages, my fit function showed a difference with the standard that has been used for three decades: Surfaces assigned a model age of about 3.5 to 3.7 billion years under the old chronology were older, by up to 200 million years. And, surfaces younger than about 3.4 billion years under the old chronology are younger, by up to about 1 billion years.

Differences Between the Lunar Crater Chronologies

The new and old chronologies in blue and red (top), and the difference between them in terms of model surface age. (© S.J. Robbins)

There are a lot of implications for this. One is that volcanism on the terrestrial planets may have extended to more recent times. This would imply that the planets’ cores stayed warmer longer. Another implication is that the large reservoirs of water thought to exist around 3 billion years ago may have existed for another 500 million years, with implications then for favorable environments for life.

But, something that I added near the end of my LPSC talk was the question, “Am I right?” The answer is an unsatisfying, “I don’t know.” I of course would not have published it if I thought I was wrong. But by the same token, this type of science is not about one person being right and another being wrong. It’s about developing a model to fit the data and for that model to be successively improved as it gets incrementally closer to explaining reality.

And, there are ways to improve the lunar chronology. One that I’m a big advocate of is more lunar exploration: We need more data, more samples gathered from known locations on the moon’s surface. We can then date those samples – either in situ or in labs on Earth – and along with crater measurements add more tie points to the lunar crater chronology function. Right now, there is a glaring gap in the sample collection, one that spans 2 to 3 billion years of lunar history. A single point in there could help differentiate between my model and the classic model. And more data would be even better.

Until we land robotic missions to send back samples from other planets or that can date samples there, the moon is still our key to ages across the solar system.

February 27, 2014

Follow-Up on Saturn’s Moon Titan, its Craters, and its “Youth”


As a quick follow-up to my last blog post, a reader wrote in and their comment was published on the Creation.com website. From Mark V. of New Zealand:

You mentioned that Titan has fewer impact craters than would be expected. Does this mean that a moon or a planet which has a lot of impact craters such as earth’s moon Mercury Mars etc. is therefore old? I would suggest that the reason for the few craters is Saturn, which with its much higher gravity, would draw the various comets meteors etc away from Titan.

The CMI (Creation.com / Creation Ministries International) astronomy guy, Jonathan Sarfati, responded (links removed):

In answer to your question, no it does not. This would be committing the fallacy of denying the antecedent, as explained in Logic and Creation. The explanation for lots of craters on the moon is a brief intense swarm of meteoroids, travelling on parallel paths, probably during the Flood year. This is supported by ghost craters, evidence of rapid succession of impacts, and by the fact that 11 of the 12 maria are in one quadrant, evidence that the major impacts occurred before the moon had even moved far enough in one orbit (month) to show a different face to the swarm. See On the origin of lunar maria and A biblically-based cratering theory.

In my original blog post, I said there were two alternative ideas to cratering that would save the creationist idea behind this article:

The alternative is that the crater calibration stuff is off, and radiometric dating is wrong. So, the Moon is not 4 billion years old, it’s 6000 years old. With the crater population of Titan, that means Titan can only be, oh, around 15-150 years old. Except that it was discovered in 1655.

Or, the entire crater calibration stuff is completely wrong. Which means you can’t use it to say Titan’s surface is young, which is what he is claiming — that it is young because scientists are showing it’s young because it has few craters.

When writing that, I specifically left out the special pleading idea even though I thought that CMI would probably try to use that in responding to anyone’s question. Which they did. The special pleading is that, “Hey, we actually can’t use the Moon as a guide to cratering because its craters came in a quick, special burst!” (that some creationists attribute to Noah’s Flood because, well, ¿why not?)

I left that out because it’s really a form of my second alternative: The crater calibration techniques are bogus, you can’t use them. By Jonathan Sarfati claiming that the lunar cratering is unique and special, it means that the cratering calibration is way off because cratering chronology is BASED on the Moon. And, if it’s off, if we don’t know how to calibrate any ages with craters, then you can’t possibly use them to say Titan’s surface is young or old, which is the basis of the claim that the CMI article is based on.

So again, this doesn’t solve the problem, it introduces more problems and shows yet again that the young-Earth creation model is internally inconsistent.

You can be a young-Earth creationist and claim Titan is young (you’ll be wrong, but you can claim it). Just don’t use the crater chronology to do it. If you do, you’ll wind up going in circles as I’ve demonstrated in this and the previous post. Why? Because it’s inherently inconsistent to do so. If the consequence of a CONSISTENT crater chronology were that Titan’s surface was <6000 years old, then that would be the mainstream science thinking on the subject. It's not. Because the crater chronology doesn't show it, if you use a consistent chronology across solar system bodies.

February 24, 2014

Under a Creationist’s Reasoning, Titan (moon of Saturn) Is Just a Few Years Old


Introduction

I’m always amazed at the penchant for young-Earth creationists (YECs) to use science for part of their argument and creationism for another part, when it relies on the science being right, but they’re arguing that the science is wrong.

If that was confusing to you, let me explain …

Crater-Age Modeling

The basic idea behind using craters to estimate the age of a surface is that, if you have an older surface, it’s been around longer and has had more time to accumulate more craters. So, more craters = older.

We can use samples from the Moon to correlate crater densities with absolute ages and get a model for how many craters of a certain size equals a certain age.

That’s the basics … if you want more, see my podcast, episodes 40 and 41: Crater Age Dating Explained, Part 1 and Crater Age Dating and Young-Earth Creationism, Part 2.

So, we have, from the moon, the idea that a heavily cratered surface equates to one that’s been around for billions of years. This REQUIRES radiometric dating to be correct and the basics of crater age-modeling to be correct.

The implication is that a surface that has just a few craters is much younger.

Titan

Titan is Saturn’s largest moon, its atmosphere is thicker than Earth’s, and the Cassini and Huygens probes have shown that its surface is geologically active. It also has very few impact craters.

YEC

Enter David Coppedge, a man I’ve talked about on this blog quite a bit. His latest writing was published by Creation Ministries International, “Saving the ‘Billions of Years’ Age of Titan.”

In his article, he is keying in on a recent popular article that explains that Titan’s surface looks young, and there are a few ways that it can still be geologically active (as in have a young surface, like Earth) and still have formed over 4 billion years ago.

The problem is that, for us to say it looks young, that’s because of the few impact craters. Versus old, that’s because of radiometric dating and then the calibration to lots of impact craters on the Moon. For Coppedge to say (effectively) “Yes, scientists are right, Titan’s surface looks young because it has few impact craters,” then he is REQUIRED to accept the basics of the crater chronology system, which he clearly doesn’t. Because, if Titan is young because it has few craters as he is agreeing with, then the Moon and other bodies must be much older under that same crater chronology system.

Yes, confusing. To get to point B, he must accept A. He thinks B is true, but he does not think A is true. Hence the confusing cognitive dissonance he just ignores.

Alternative

The alternative is that the crater calibration stuff is off, and radiometric dating is wrong. So, the Moon is not 4 billion years old, it’s 6000 years old. With the crater population of Titan, that means Titan can only be, oh, around 15-150 years old. Except that it was discovered in 1655.

Or, the entire crater calibration stuff is completely wrong. Which means you can’t use it to say Titan’s surface is young, which is what he is claiming — that it is young because scientists are showing it’s young because it has few craters.

Final Thoughts

Does anyone have a headache now? I think I gave myself one.

June 29, 2012

An Interview with Me About Lunar and Martian Craters


Quick announcement ’cause I forgot to do it earlier and I forgot to mention it on the last podcast: Nancy Atkinson, a reporter of Universe Today (among other things), interviewed me last-minute last week about lunar and martian craters. The interview’s about 15 minutes long and was broadcast to both 365 Days of Astronomy podcast and the NLSI (NASA Lunar Science Institute) podcast.

Link to NLSI podcast page.

Link to 365 Days of Astronomy page.

The description, as Nancy wrote it:

Description: It’s a showdown! The Moon Vs. Mars. These are two very different planetary bodies. But there’s one thing they have very much in common: both are covered with craters. So how do the two compare in the crater department? With us to give us some blow by blow insight is Stuart Robbins, a researcher at the University of Colorado Boulder and the Southwest Research Institute, and he also works with the CosmoQuest Moon Mappers citizen science project.

Bio: NLSI brings together leading lunar scientists from around the world to further NASA lunar science and exploration.

Stuart Robbins in a Planetary Geologist with a PhD in Astronomy. He works at the Southwest Research Institute and the University of Colorado, Boulder and is the science lead for the Moon Mappers project.

June 26, 2012

Podcast Episode 41: Craters and Creationism, Part 2


In a slightly delayed offering, episode 41 has been posted. Sorry to say that episodes over the next month may be delayed by a few days, as well, for I have several trips coming up and won’t have my equipment with me.

As the title suggests, this episodes details a few claims by creationists to try to argue that craters really show the solar system is only 6000 years old instead of the solar system being around 4.5 billion. It may get a bit technical at times — sorry.

June 16, 2012

Podcast Episode 40: Crater Age Dating Explained, Part 1


This is a bit of a longer episode. ‘Cause, this is what I do.

I give you a pretty detailed overview of how crater age dating works, the difference between absolute and relative age dating, how we can assign absolute ages to the relative ages of craters, how geologic mapping works and why it’s important for crater age dating, and then many of the known problems and caveats with the method.

Finally, there’s an open question about the puzzler: Is it worth doing? I wanted to do it initially to get interaction between me and the listeners. But participation has been around 1 for each. So if you have any opinion regarding the Puzzler, please let me know in the Comments to this post.

April 8, 2012

Podcast Episode 30: Was the Asteroid Belt a Planet? Part 2 (Exploding Planets!)


The follow-up to last episode, this one deals with Tom Van Flandern’s idea that Mars was a moon of an exploded planet that formed the asteroid belt 65 million years ago. So, last episode was basic science, this one gets back to some of those wacky and wonky ideas. Oh yeah … and lots of Coast to Coast clips!

I also spend around 10 minutes discussing feedback from the last episode.

October 5, 2011

Playing Hide-and-Seek with the Apollo Landers


Introduction

This post is less about “pseudoastronomy” and more about what you (or anyone) with an internet connection can do with the amazing pictures taken by NASA’s Lunar Reconnaissance Orbiter. Though I suppose it’s also related to the Apollo Moon hoax in that we finally have a camera in orbit that’s capable of seeing the Apollo landers.

The Instrument

The Lunar Reconnaissance Orbiter (LRO) spacecraft has been in orbit of the moon for nearly three years. It has a suite of instruments onboard, though the one we want for this exercise is called the Lunar Reconnaissance Orbiter Camera (LROC). This camera actually has two “lenses” on it — a wide-angle camera (WAC) and a narrow-angle camera (NAC).

The spacecraft is in an orbit that, with the field of view of the cameras, allows WAC images to have a pixel scale of 100 meters, and the NAC has a pixel scale of about 50 cm (0.5 meters, or about 20 inches). And that’s just cool.

So we’re using LRO’s LROC’s NAC. Lots of a.c.r.o.n.y.m.s. Each NAC image is about 2.5 km wide and generally about 50 km long – a tiny fraction of the surface of the moon.

What to Do

You could use the LROC image search feature and find the Apollo landing coordinates from Wikipedia or some other source, put them into the search, and go searching for the Apollo sites that way.

You could cheat a bit and use this website’s list of NAC images with the Apollo landing sites in them (that’s what I did). Then you can use the LROC image search and search for that exact image and click on it. Or, you can directly go to the URL http://wms.lroc.asu.edu/lroc/view_lroc/LRO-L-LROC-2-EDR-V1.0/M113853974RE and replace that last string of letters and numbers (M113853974RE in the case here, which is for the Apollo 16 landing site) with the image ID.

Then, search! You can use the Flash-based tool that the LROC team has set up on that page to zoom in and out and search for the landing site, or you can download a TIFF image (generally around 20-50 MB) from the link towards the top (“Download CDR PTIF”). Sometimes using the information and image on the site with the list helps you to find it more easily.

But while you’re searching, you’ll find a lot of other interesting features. You could find the Apollo 17 “Challenger” descent stage along with the astronaut tracks (story about that on the LROC site here). And if you end up liking treasure-hunting on the moon, you may find Moon Zoo a citizen science project, of interest.

When identifying the NAC images to look through, one thing to pay attention to is the “incidence angle” or “solar altitude” which tells you what the shadows are going to be like. You may think that it’s best to see these when the sun is directly overhead (solar altitude is 90°, or incidence angle is 0°). But, this isn’t actually the case, You want longer shadows so that the features are easier to see. Incidence angles closer to 60-80° or so are generally best (solar altitude 10-30°).

But don’t take my word for it — try looking at the same landing site under an 80° incidence versus a 10° incidence angle. While the craters are much harder to see and the landing sites look more like brightness features rather than “3-D” because of the lack of shadows, you’ll see things like bright crater ejecta and dark crater ejecta that the lower sun angles made invisible!

Final Thoughts

Maybe it’s just me, but I actually find this kind of thing fun (I spent an hour looking for Apollo 15 last night in 5 different lighting conditions). It also gives you a nice perspective on the relative sizes of things — not necessarily that the Apollo hardware was “small,” but really how BIG the moon is, and how much we have left to explore.

If the solar system were reduced in size such that the sun were a grapefruit (about 10 cm), Earth would be located about 11 meters away. Humans have traveled a mere 2.8 cm, or about 1 inch, into the solar system.

I also find it absolutely amazing that in this day and age, there are still people out there who don’t think we ever landed people on the moon.

P.S. Please remember my comments policy. I consider anything related to UFOs to be off-topic for this post.

March 28, 2010

When Encyclopedias Are Bad: A Closer Look at Conservapedia – “Mars”


Introduction

Last week, I wrote an article about how Conservapedia calls “black holes” and “dark matter” “liberal pseudoscience” in a very “huh?” moment. It still is confusing to me why they would waste mental energy on calling those things “liberal pseudoscience.” But I digress.

I thought I might take a closer look at some of their actual astronomy articles. Since I’ve been studying Mars for the last 4 years fairly in-depth, looking at their article on Mars seemed like a natural article to take a peek at.

I found what I expected – creationism and “problems for evolutionists” – but I also found what I didn’t expect – gross errors in information and zero references to back up most of what was stated.

The Good

I’ll start out by showing that I’m not completely out to “diss” Conservapedia. Their article has some good things. It correctly states that Mars is the 4th planet from the sun, for example. It gives the interesting factoid that researchers with missions on the planet will often adopt a “Mars day” work schedule that’s about a 25-hr day (as opposed to Earth’s 24-hr day). It talks correctly about what causes seasons on Mars. It even (mostly) correctly discusses the whole “face on Mars” issue.

The “Eh, That’s Wrong, But It’s Minor”

Let’s first deal with some assertions. Specifically, near the beginning, it states that Mars’ 26-month synodic period makes it a “particularly difficult object to explore, [sic]because opportunities to launch a rocket probe to Mars occur so far apart in time.” Rather, Mars is pretty much the easiest planet or planet-like object to get to by spacecraft, except for our moon. It’s close by, there’s NO WAY that the world’s space programs are funded enough to make craft to visit the planet more often than every ~1.5-2 years, and we can actually land on it and survive as opposed to the actual closest planet to us – Venus.

Towards the end, it discusses exploration of Mars. It states, “Mars has been the subject of more attempts to explore it, and more failures, than any other planet.” This is wrong. To-date, at least based on NASA’s Chronology of Venus Exploration and Chronology of Mars Exploration, Mars has had 40 missions, while Venus 43. Minor, but still a mistake.

Under their “Young Mars Creation Model” (see below for more on that), it states, “Discoveries by the Mars Excursion Rover Opportunity have led …” Unfortunately for Conservapedia, The MER craft acronym stands for, “Mars Exploration Rover,” not “Excursion.” Minor, but slightly humorous.

The Bad

Note: This section will not address the creationist stuff, look to the next for that.

I was reading through the page and the biggest thing to stand out was the following two paragraphs:

“Mars contains the largest of three major geologic features in the Solar System. The largest impact basin, the largest volcanoes and the largest canyon are all found on Mars and in a clear relationship to each other. This relationship provides the key to understanding Martian geology.

“Mars’ largest impact basin is called Hellas. As shown in the topography map, on exactly the other side of Mars from Hellas is Mount Alba Patera, the largest volcano by surface area. This antipodal juxtaposition suggests that the Hellas impact caused the eruptions of Alba Patera and the volcanoes of the Tharsis plateau to the south and southwest. To the east is found the gigantic rift valley called Valles Marineris.”

Alright, there are a few things here. First, a very minor one. “Alba Patera” is the name of the volcano, not “Mount Alba Patera.” When features were originally assigned names when we got the first good images back from spacecraft, “Mons” (singular) / “Montes” (plural) were given to very large and obvious mountains, “Patera” (singular) / “Paterae” (plural) were assigned to very large, irregularly shaped features, and “Tholus” (singular) / “Tholi” (plural) were assigned to “small” mountains or hills. Nothing has two designations. And later imagery revealed some of the montes, paterae, and tholi were volcanoes.

Moving on, I don’t want to concentrate on the whole Alba Patera is antipodal to Hellas Basin. Suffice to say, the ages don’t really work out. It’s possible, but it is no way a given that this is the case.

Rather, I want to focus on the other information given on Hellas: According to this article, Hellas Basin is the largest crater on Mars, and it’s the largest crater in the solar system. Wow.

In a word: NO.

First off, let’s put some numbers down. Hellas Basin< is very roughly 2200 km across and about 9 km deep (it’s difficult to measure the diameter because no one actually knows where the rim is, so you have different people making different estimates). For comparison, that’s just friggin’ big. It’s well over half the size of the United States.

But it’s not the biggest in the solar system, and it’s not even Mars’ largest.

Check out Utopia Planitia on Mars. It’s pretty much due north of Hellas, and it pre-dates Hellas by roughly 400 million years. It is also roughly 50% larger than Hellas, having a diameter of about 3300 km and being about 4-5 km deep on present-day Mars. Now that’s big. But to be fair, I suppose that Conservapedia’s article can be saved if we say that by “biggest” they mean “deepest.” Oh, and if you want to play around on Mars, looking at various features, I highly recommend Google Mars.

Anyway, Utopia is by far the largest impact basin on Mars. Or is it? The largest topographic feature on Mars is its crustal dichotomy – the north is low and flat and young (at least its visible surface), while the south is high and hilly and old. Again, check out Google Mars and zoom out. There have been many, many explanations proposed for this dichotomy, but the latest one to be shown to be viable is that of a really really big impact, very early in Mars’ history. Being a guy who studies craters, I like this idea, but I do think it has awhile to be shown somewhat conclusively. In this case, it is possible that even Utopia is just second place to an impact “basin” that covers nearly half the planet.

Moving on, though, we have the moon. Discovered on the lunar far side about 50 years ago resides the South Pole-Aitken Basin. This thing is also big. It’s about 2300 km in diameter – so bigger across than Hellas but not Utopia – but a whopping 13 km deep. So now, our goal of saving Conservapedia’s article by saying “biggest” means “deepest” doesn’t work, either. Oh, and there’s also Google Moon to have fun with.

The Creationist Take

In any normal article talking about Mars, I don’t think anyone would expect sections about young-Earth creationism. But, *gasp*, Conservapedia does.

It first shows up in the discussion about Mars’ magnetic field. There is none. There are pockets of crustal magnetism that locally are stronger than Earth’s, but there is no global magnetic field. In the section on Mars’ “magnetosphere,” it directly refers to Russell Humphreys, who is a creationist whose ideas I’ve discussed on this blog before.

It next comes up in the entire section on, “Problems for Uniformitarian Theories” (that’s code for old-Earth) that talks again about Mars’ magnetic field. Except, rather, it talks more about how Mercury’s magnetic field is an open question for astronomers rather than Mars’.

Finally, we get to the entire section, “Young Mars Creation Model.” I’m not entirely certain how anything that they discuss in the section actually supports their conclusion of: “This shows that, like Earth, Mars has evidence that it is only a few thousands of years old and not 4.6 billion years old.”

It does state, “The dating of [Hellas basin formation triggering Alba Patera’s volcanism] from craters places it at about the time of the Great Flood on Earth.” Of course, this is completely uncited. But being someone who actually studies craters on Mars and has the largest database of said craters in existence, I can unequivocally state that the craters on Mars’ present-day surface show it to be ancient – over 4 billion years old.

Final Thoughts

Perhaps I’m being unfair. After all, the editor of the page that put up the bulk of the information I talked about has no background in astronomy. Rather, he’s in charge of Conservapedia’s attempt to re-write the Bible. And in the spirit of Wikis, perhaps I should attempt to edit the page myself to make the corrections (fat chance …).

But rather, I think this serves as an example of two things. First, it’s another example of how Conservapedia should not by any stretch of the imagination be considered a good source for scientific information.

Second, it shows that encyclopedias in general should not be taken as gospel. Students should not use them as their source material. They may use them as a starting point, but they need to look at the references, evaluate them, and in the end find actual original source material.

February 2, 2010

On the Importance of Scientists to Publish in the Scientific Literature AND Other Venues


Introduction

This post isn’t actually about the process of peer review. It isn’t about the importance of press releases. It’s not about scientists going to conferences and hobnobbing with colleagues. Rather, it’s a tale of hope, joy, and crushing disappointment.

My Research

For very astute readers, you may have picked up bits and pieces of my current research, though I’ve never actually gone into any depth on this blog as that’s not the point of the blog. However, it forms the backdrop of this tale of woe:

My work has – for the past two years and for another year yet to come – been to create a new database of craters on Mars, statistically complete to diameters of about 1.5 kilometers. That’s about 170,000 craters larger than that size, though the database has around another 110,000 craters that are smaller in order to ensure statistical completeness. One of the goals of this database is to study a particular type of crater against the backdrop of other “less interesting” craters. The type I’m studying in particular are known as “lobed craters,” craters with “lobate debris aprons,” or “layered ejecta” craters. Everyone has their own pet term though the Mars Crater Consortium has tried to standardize nomenclature for them to be “layered ejecta.” The picture below illustrates a simple example of this type.

Single-Layered Ejecta Crater, Mars

Single-Layered Ejecta Crater, Mars

The basic idea is that this crater’s ejecta is very cohesive and does not look like typical ejecta that we observed on the moon for years before we went elsewhere in the solar system. Layered ejecta craters exist almost exclusively on Mars, though a few have been observed on some of the outer planet satellites, namely Ganymede and Europa.

The main hypothesis for their formation is that the impactor hit a surface that had solid volatiles in it (as in ice). The volatiles melted into the surface from the impact energy and caused the ejecta to act as a cohesive “mudslide,” giving the appearance we see today.

Moving Forward – The Discovery

Now, in my research, I’ve noticed that double-layered ejecta (craters surrounded by not just one, but 2 layers of this cohesive ejecta) seem to be concentrated around volcanic terrain on Mars. While I was busy cataloging and outlining these lobes a few weeks ago, I noticed that there was a marked increase of the double-layered ejecta in a certain region of the planet. But there wasn’t a volcano there, I thought.

I zoomed out on the map I was using and, lo!, I saw what appeared to be a volcano. In fact, the caldera of this thing was about 75 km by 90 km, or around 50% larger than the state of Delaware, several times larger than the caldera of the Yellowstone supervolcano. This size would put it easily in the top 25% of caldera sizes on the planet Mars.

Taking a step back, another, side-project that I’m working on is creating mosaics of the large volcanos of Mars and performing crater counts within them in order to develop a timeline for the “last gasps” of volcanism. I had a list of 24 volcanos that I had obtained from the USGS last summer, since they keep lists of things like that. And I knew that this new caldera I found was not on my list.

Checking Around

So my next step was of course to check all the lists of known volcanos that I could find for Mars. I re-checked USGS. I even checked Wikipedia. But this feature that looked like a caldera was not on them.

Unfortunately, my advisor was in Antarctica searching for meteorites, so I could not consult with him. Rather, I talked to the post-doc next door, who looked at it and agreed with me that it appeared to be a volcano. On a day when his officemate was there, another post-doc, I asked her, and she wasn’t as certain that it was a volcano, but said it was possible. She suggested I check with some other people outside of the university, but I wanted to wait until my advisor was back to check with him … after all, I didn’t want to make myself look like a fool in front of possible future colleagues.

Spreading the Possible Word

Meanwhile, I was getting excited. I mean, who wouldn’t? I tried not to get my hopes up, but from what I could tell, this thing sure looked like a volcano, not a crater (I knew what an impact crater looked like … I’d been circling them for years). And it wasn’t on any of the lists for Mars volcanos. So I mentioned it to a few people, including a comment on The Conspiracy Skeptic podcast episode from a week ago that some of you may have listened to.

Advisor Returns

My advisor got back to this continent this past weekend and we arranged a meeting for yesterday (Monday) to go over progress on what I’d done for the past 10 weeks while he was gone. I told him the first thing I wanted to talk about was this possible volcano to see what he thought. He seemed fairly excited, too, and I think had briefly looked at it and thought it looked promising.

I went into his office at 1 for our meeting and sit down on the couch, and I said that the first thing to talk about would be this possible volcano discovery. He said something to the effect of, “Yeah …” and handed me a paper, turned to a color picture, with big arrows pointed at my volcano.

The Reaction

I was not happy. Duh. But, as far as I could tell, I had taken the right steps. I’d identified a feature I thought was something interesting. I’d created a high-resolution image of it. I’d checked with a few people, and I’d looked at the standard lists.

The paper that this was tucked away in didn’t have a revealing title, so it’s also not as though I had something I could easily search for. At the time of writing this, I can’t actually find the paper in question, though I did just find an abstract for a conference from 2008 where they identify it. Sigh. The abstract is entitled, “New Evidence for a Magmatic Influence on the Origin of Valles Mariners.” Their paper from last year had a similar title. As you can see, nothing in the title about “volcano.”

Final Thoughts – The Moral

The point of discussing this in my blog is to point out the importance for scientists that, once they make a discovery, they need to not just publish in the standard scientific literature. They also need to make sure that it makes its way to other publications, such as standardized lists so that other people don’t get their hopes up on making a discovery others know of it and can easily find that information rather than doing a very exhaustive literature review. The USGS lists are meant to be used by people as a guide for this sort of thing. But, in my bitter opinion, this was a “science fail” by the authors in terms of publicizing their discovery.

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