65 million years ago, there was

one last perfect day on Earth.

Painting, "K/T Hit" by Donald E Davis.  Prints available at http://www.donaldedavis.com

Dinosaurs terrorized the world for 160 million years.  However, chance presented a lesson in fate that reset the biological clock: geologic evidence reveals the Earth was struck by a comet or asteroid 65 million years ago thus ending their reign.

Traveling a course that brought it in from over the southern Atlantic and heading in the general direction of what is today, Seattle, Washington, the impacting object entered the atmosphere at a shallow angle of about 30°.  Though analogous to a single grain of sand striking a basketball-sized rock, the object held tremendous kinetic energy, every bit of which would be imparted to the Earth.  Moving with a terrific speed of roughly 25 miles per second, it split the planet's thin layer of air with ease and "plunged" into a shallow tropical sea where part of the Yucatan Peninsula exists today.  At roughly 6 miles in diameter, the object would have towered above 1/6 of the atmosphere's thickness, and the sea -- around 300 feet deep -- would have been as though a puddle to a cannonball.  A crater nearly 160 miles wide and 80 miles deep was blasted into the Earth.  Our planet still bears this scar now buried under 1/5 mile of sediment.

The above image depicts the object’s violent impact and the crater's formation about 45 seconds into the event as sulfate-rich target rock of the seafloor is ejected high above our planet's atmosphere from where it will reenter to cause worldwide forest fires.

A storm is coming... the sky about to be set ablaze.

Painting, "Sudden Death" by Chris Baker.  Prints available at http://www.sciencecenter.net/butlerart/index.htm

With moments to live, the young tyrannosaur turns to run for shelter from a sudden and unfamiliar dawn.  When the shockwave reaches her, land and sea will be shattered, and 75% of all living species will go extinct forever changing the natural history of the planet.  Mammals stand on the cusp of inheriting the Earth.  About to suffer a global odyssey, our ancestors will survive this trial by fire.

Earth becomes a crucible of acid and darkness

Digital art, "Venus" by Joe Bergeron.  Prints available at http://homepage.mac.com/joebergeron/

Following the impact, Earth is more like Venus than we are accustom -- especially near ground zero where a thick, hummocky layer of hot ejecta completely blankets the lifeless surface up to 300 miles from the point of impact.  Farther out, the ejecta is laid down discontinuously, and still farther, a thin sheet of fallout dust enriched in Iridium and sulfates will eventually be deposited worldwide.

Shrouded in brown sulphuric acid clouds that precipitate acid rain, the Earth's plants and animals are cast into four months of cold and darkness.  Tropical organisms needing a more temperate climate rich in food and sunlight are less able to shoulder this battery of conditions they have not evolved to endure.  However, those living near higher latitudes are already well adapted to tolerate the extended gloom, low temperatures, and lack of food as they normally do every winter.  These hearty species will survive where others face extinction.

Chicxulub – The Horns of the Devil

Schematic map by the American Geophysical Union.  Gravimetric map by the Lunar and Planetary Institute.

    Above, the arrow on the globe points to a box enclosing the schematic map (middle).  Click the schematic map and the gravimetric intensity map (right) to see enlarged views.  Note that the gravimetric intensity map does not show topography.  Rather, the peaks and valleys show the gravitational intensity at that location and to a certain extent, mimics the topography of the buried crater.  The colors simply help to visualize the different intensities.

Impacts Today?

Paintings by Donald E Davis.  Prints for sale at http://www.donaldedavis.com

    The two thumbnails above depict much smaller events -- The left painting shows a fictitious air burst (similar to that at Tunguska on June 30, 1908) over Los Angles on an otherwise beautiful day.  The city is a fraction of a second away from total annihilation.  The painting on the right depicts an actual fall over Alaska on December 9, 1997.  Click the images to see enlarged views; they're wonderful paintings.

    There is some evidence to suggest the Chicago fire and Peshtigo fire in October of 1871 were each caused by comet fragments impacting the earth.

This page was last updated on 07/26/01

To make a comment, ask questions, report problems, etc., please contact

Reuben Johnson at: rcjohnson@students.wisc.edu