"Definitive proof" of Mars water

Mars' landscape was formed by flowing water, and the proof is in the pebbles. [BBC]

Exploding things for science

Earlier this month, volcanologists blew 12 holes in an otherwise peaceful meadow in Ashford, New York. It's not that they had anything against the meadow, per se, it's just that it was a convenient place to do some real-world experiments in how explosions affect the Earth and what we can do to monitor and predict volcanic eruptions.

Did a volcanic eruption nearly kill off ancient humans?

Short answer: We don't know. What makes this story by Erin Wayman interesting is the way it carefully breaks down an almost Hollywood-ready narrative and finds the fascinating uncertainty lurking underneath. The truth is, uncertainty is cool. Because it means there's more stuff left to discover.

How to: Build a better sand castle

Geoscientist Matt Kuchta explains why wet sand makes a better castle than dry sand — and what you can do to make your sand fortress even more impenetrable. Hint: The secret ingredient is window screens.

What makes dry quicksand so deadly?

Dry quicksand was a mythical substance — normal-looking sand that could swallow you in a flash. That is, until 2004, when scientists made the stuff in a lab. (Mark told you about that development.)

In this video, geologist Matt Kuchta explains how dry quicksand is different from both wet quicksand and stable sand. Hint: Think "Jenga".

Instant gold

Under the right conditions, veins of gold can form in just a few tenths of a second, writes Richard Lovett at Nature News. The key is the massive changes in below-ground pressure that can accompany an earthquake. Under the right conditions, water vaporizes, leaving behind crystallized minerals.

Ancient forest off the coast of Alabama

Sixty feet under the Gulf of Mexico lie the remains of an 50,000-year-old forest. Diver and photographer Ben Raines took some amazing photos of the site and sent samples of the trees — which still look like trees — to the Lawrence Livermore National Laboratory for radiocarbon dating. You can see sap in a cross-section of the wood and, when it's cut, Raines says it still smells like fresh cypress.

Sinkholes: Swallowing everything, including the kitchen sink

If you were horrifically fascinated (horrafinated?) by the sinkhole that swallowed Floridian Jeff Bush and his entire bedroom a week ago, you might be interested in some sinkhole science. The US Geological Survey says that sinkholes are a geologic thing. Certain areas of the country are more prone than others (which you probably knew already). But the formation of actual sinkholes in those sinkhole-prone environments can apparently be prompted by human activities, ranging from old mines that weaken the ground above them; to groundwater pumping that destabilizes the soil; to (get this) leaky faucets. The USGS does not say how many leaky faucets, or how bad a leak, it might take to trigger a sinkhole, but the basic idea is that saturating usually dry soil could cause it to shift, so you'd assume it would have to mean a lot of water leaking into the soil under the house.

The birth of a volcano

On February 20th, 1943, Dionisio Pulido watched as a crack in his farm field collapsed in on itself and began to vomit out ash, rock, and fire. The birth of Mexico's Parícutin volcano is a story I've heard before, but I really enjoyed Dana Hunter's two-part series on the occasion of its 70th volcanaversary. Her posts really get into the perspective of Pulido and other local residents in a way I haven't seen in other accounts, and she does an amazing job of giving you a sense of just how well-documented the birth of this volcano was and why that fact matters so much. Here's Part 1 and Part 2.

What we can learn about volcanic eruptions from the vehicles trapped in their path

The car in this photo was 13 kilometers northeast of Mount St. Helens when that volcano erupted on May 18, 1980. This photo was taken about a month later by researchers from the United States Geological Survey. At the Rosetta Stones blog, Dana Hunter has a really fascinating story — with more eerie photos — about why geologists would want to study totaled vehicles and what we can learn from machines that we can't learn from people.

The art and science of searching for water

The United States Geological Survey has an interesting FAQ report on dowsing — the practice of attempting to locate underground water with divining rods. It's got some interesting history and comparisons between dowsing and modern hydrology. The part on evidence for and against dowsing, though, is pretty sparse. If you want more on that, The Skeptic's Dictionary has some deeper analysis. The basic gist — what little research there has been suggests the successes of dowsing aren't any better than chance. (Via an interesting piece by Mary Brock at Skepchick about dowsing in the wine industry.)

Are these the remains of ancient worm holes?

Here's a weird, great geological feature I spotted yesterday while out hiking in rural Oklahoma. We were out in a flat, flat plan that was dotted with a few tall, angular sandstone mounds and narrow sandstone canyons carved out by erosion. This rock was sticking out of the side of one of the mounds. It was the only place we saw anything like these vertical, tube-like structures, which stretched from the ground up to probably about my shoulder.

When I posted this image on Twitter yesterday, several people suggested that the tubes might be skolithos — tube-shaped fossils that were probably made by some kind of ancient worm creature and turn up sometimes in sandstones. While the pictures on Wikipedia don't look very similar to what I saw, there are apparently lots of different forms these things (and similar tube fossils) can take.

Defeating earthquakes, and more free videos from the American Geophysical Union

Remember when you had to build a bridge out of popsicle sticks in high school science class? The goal was to construct the miniature bridge that could withstand the most physical stress. Your materials were just sticks and glue. So the real challenge was to find strong shapes.

On the day of testing, we all learned very quickly what those shapes were. Bridges built out of lots of squares collapsed almost instantly. Bridges built out of triangles made the finals.

This is a pretty basic lesson, but it's not one that the global construction industry has learned yet, says the US Geological Survey's Ross Stein. Last week at the meeting of the American Geophysical Union, he began a talk on "Defeating Earthquakes" by demonstrating the difference between the cube-centric structures we build all over the world and how much stronger those structures can be if you just add triangles in the corners. It's a powerful demonstration of how simply having the technology to solve a problem isn't enough. You have to get people to use it.

This whole video is worth watching and easy for laypeople to follow. And it's just one of a huge collection of lecture videos from AGU 2012 that are now available online. They cover everything from the chemistry of lighting to the geology of volcanoes to the effects of space storms and solar flares. Very cool stuff!

Math + Too Much Free Time =

Here is a detailed analysis of the amount of time it would take to ride a hypothetical elevator down through the Earth's core and back out the other side of the planet. Apparently, this has something to do with the remake of Total Recall. But it's interesting even if (like me) you have no intention of seeing that movie. (Via Rhett Allain)

The evolution of Creationism

One of the great mythologies of any kind of religious fundamentalist movement is that the beliefs of that movement, and the way they choose to interpret their scripture, represent some kind of true reflection of history. This is how things always were. It's the people who believe differently who changed.

But that's not necessarily true. Take fundamentalist Christianity. A few weeks ago, the Slacktivist blog had some excellent posts recently, documenting the fact that evangelicals were once pro-choice. Another great example comes from an article in the Geological Society of America Today — the magazine of the GSA.

Written by the University of Washington's David R. Montgomery, the piece traces the birth of modern Creationism and the way it has changed since the 19th century. In general, he writes, you can really think of Creationism as a response to geology — arising as a backlash against the rise of modern geology.

The roots of modern creationism run directly back to George McCready Price (1870–1963), an amateur geologist with no formal training. In a book designed to look like a geology textbook, Price (1923) asserted that there was no order to the fossil record. Rejecting the idea of fossil succession, he argued that the succession of organisms that geologists read in the fossil record was really just a mixed-up sampling of communities that lived in different parts of the antediluvian world. He considered the fossil record too incomplete to confidently reconstruct the past, citing the occasional discovery of animals thought to be extinct and known only from fossils.

Leading fundamentalists praised Price’s book, calling it a “great and monumental” work of an “up-to-date scientist”—“a masterpiece of real science” by one of “the world’s leading Geologists,” and “the sanest, clearest and most irrefutable presentation of the Science of Geology from the standpoint of Creation and the Deluge, ever to see the light of day” (Numbers, 1992, p. 98). But even some of Price’s most ardent supporters had questions about his new flood geology. In a 1924 review in the evangelical journal Bibliotheca Sacra, the editor credited Price with throwing “a wrench into the smooth running machinery of the evolutionary theory” butwondered why it was that when fossils were found in the wrong order, they were always in exactly the reverse of that predicted by geologists (Numbers, 1992, p. 95). How could strata have gotten flipped upside down after Noah’s Flood laid them down if the Bible did not mention subsequent catastrophes? Despite such qualms, fundamentalist proponents of flood geology were inclined to assess Price’s credibility by the conclusions he reached rather than the strength of his arguments or evidence.

Read the full article online

Image: David Montgomery's photo of Siccar Point, Scotland. Montgomery writes, "the contact between the gently inclined Devonian Old Red Sandstone and vertically dipping Silurian graywacke that established a compelling case for the vast scope of geologic time. The expanse of time required to uplift and erode the two mountain ranges that were the source for the sand in these deposits was unimaginable to [James] Hutton."

Via Cort Sims