Historical Science and the Case of T. rex’s Puny Arms and Dinosaur Diets

An scan of a page from Ken Ham's "Dinosaurs in Eden" book. Here we can see Tyranosaurus-like dinosaurs with small arms enjoying a diet of flower plants.

Everyone has encountered a T. rex in books, movies or museums.   Besides its size and menacing jaws one of the most striking features of a T. rex is its diminutive arms.   So why were the arms of T. rex so short?   There have been many hypotheses including: 1) they had no use and […]

Historical Science and Perceptions of Age: Craters on Mars

A "young" crater on Mars.  This is a young crater about 30 feet (9 meters) in diameter. How young? The blocks of material ejected from the crater-digging impact sit on top of the sand ripples near the crater. This suggests, from the estimated age of the area's sand ripples, that the crater was formed within the past 100,000 years. The dark sand inside the crater attests to the mobility of fine sand in the recent era in this Meridiani Planum region of Mars.  Image credit NASA/JPL-Caltech

Our perceptions of the age of an object are frequently based on our common experience but I have found that for many people those common experiences are of little help when it comes to examining objects for which a person has no experience at all.   A couple of years ago this really hit me as […]

Geological Context V: Human Fossil Footprints Found Below Ice Age Deposits


A story is breaking today of a significant fossil find that was made almost a year ago but kept under wraps until the significance of the find could be evaluated.   What has now been reveled is that over 100 footprints were found in newly uncovered rocks along a shoreline of England.  Careful analysis of […]

Fishing for Fossils in the North Sea: The Lost World of Doggerland

The skull of a mammoth is loaded on board a fishing vessel on the North Sea

Imagine trawling for fish and when you pull up your nets you find a massive bone or a huge tooth along with your catch.  For over 100 years fishermen in the North Sea between Britain and Denmark have found such items in their nets but it wasn’t until the 1980s that the items that their […]

Desert Varnish: A Crude Marker of the Passage of Time

Petroglyph carved into desert varnish found in Dinosaur National Park

Anyone who has spent time in a desert has probably noticed many dark streaks or patches on the rocks.  I expect that most people simply look at these dark streaks and think they are simply stains like a stain on a cement driveway or that line of rust color running down a wall from a […]

NH Photography: Desert Varnish Around Moab UT

Sandstone cliffs overlooking the Colorado River just west of Moab UT.  Photo: Joel Duff

Travel to most any desert region and you will observe black, brown or orange streaks or crusts on the surface of many rocks.  These stains on the rock have been called desert or rock varnish.  The origins have been scrutinized for many years and still are not fully understood. I will explore some of what […]

Cosmogenic Dating Methods Allow Estimates of Erosion Rates on Mars

Layers of rock seen at yellowknife bay in Gale Crater of Mars by the Curiosity Rover.  Image: JPL/NASA-Caltech

Just how fast are some rocks on Mars eroding?  A few months ago I asked a Martian rock that question (see: My Interview with a Martian: A Story of Origins) and I was not given a very satisfying answer.  Well, that rock can be excused for being a bit confused about time given how boring […]

NH Notes: Curiosity Update – Scenes on the Way to Mt. Sharp

A view from under the Curiosity rover showing two of its six wheels. If you look closely you can see that they have many small pits in the aluminum showing the wear and tear they have received from driving on this rocky ground. Image: JPL/NASA-CalTech

Curiosity keeps chugging away across the floor of Gale Crater.  A few weeks ago we talked to a rock  (My Interview with a Martian: A Story of Origins) that it met as it is working its way to the base of Mt. Sharp.  I had mentioned that the trip has been a tad boring compared […]

NH Notes: Inverted Valleys – A Question of Age

Petroglyph at Petroglyph Park in St. George.  There are thousands of Anasazi petroglphys in the area attesting to the fact that the boulders and rocks in this area have barely eroded at all in the past couple thousand years.

Inverted valleys formed from lava “rivers” and ancient stream beds are one of many unusual geological phenomena found in Utah.  The rocks speak in Utah and they speak very clearly because they readily reveal so many clues about their origins since they are so visible to us.   Some of the most powerful testimonies of […]

NH Notes: Ancient Lava Flows and Inverted Valleys in Utah

Former valley floor covered with lava is now a flat topped hill with an airport.

How does a hill get a flat top?  The picture below is a Google Maps satellite image of St. George Utah. To the left you can see an airport. This airport is on top of a long hill whose top is well over 100 feet above the city below.  The airport was built here because […]


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