Geologists have discovered a new way of estimating the size of impacts from meteorites.
Courtesy of NASA

Geologists Discover New Way of Estimating Size and Frequency of the Impacts of Meteorites
News story originally written on April 11, 2008

Scientists have developed a new way of determining the size and frequency of meteorites that have collided with Earth. Meteorites contain a rare element called osmium, and they have different levels of this element than the levels normally seen in the oceans on Earth. When a meteorite hits the Earth, the osmium is released where the meteorite landed. If it lands in the ocean, the osmium mixes in the ocean very quickly. Eventually these new levels of osmium settle into deep-sea sediments. Scientists can collect samples of the sediments many years later and learn about the meteorites that hit the Earth in the past.

By studying deep-sea sediments, scientists have learned that the size of the meteorite that likely plummeted to Earth at the time of the Cretaceous-Tertiary (K-T) boundary 65 million years ago was four to six kilometers across. The meteorite was the trigger, scientists believe, for the mass extinction of dinosaurs and other life forms.

One of the scientists involved in this study, François Paquay, said that this new technique will allow scientists to learn more about many other meteorites that have hit the Earth.

Last modified April 28, 2008 by Becca Hatheway.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Meteors

Meteors are streaks of light, usually lasting just a few seconds, which people occasionally see in the night sky. They are sometimes called "shooting stars" or "falling stars", though they are not stars...more

Triggers of Volcanic Eruptions in Oregon's Mount Hood Investigated

Scientists have learned that Mount Hood, Oregon's tallest mountain, has erupted in the past due to the mixing of two different types of magma. "The data will help give us a better road map to what a future...more

Oldest Earth Mantle Reservoir Discovered

The Earth's mantle is a rocky, solid shell that is between the Earth's crust and the outer core, and makes up about 84 percent of the Earth's volume. The mantle is made up of many distinct portions or...more

It’s Not Your Fault – A Typical Fault, Geologically Speaking, That Is

Some geologic faults that appear strong and stable, slip and slide like weak faults, causing earthquakes. Scientists have been looking at one of these faults in a new way to figure out why. In theory,...more

Lower Solar Activity Linked to Changes in Sun's Conveyor Belt

The sun goes through cycles that last approximately 11 years. These solar cycle include phases with more magnetic activity, sunspots, and solar flares. They also include phases with less activity. The...more

Growth Spurt in Tree Rings Prompts Questions About Climate Change

Studying tree rings doesn't only tell us the age of that tree. Tree rings also show what climate was like for each year of a tree's life, which means they can tell us about climates of the past and about...more

Did Life First Develop in a Mica Sandwich at the Bottom of a Primordial Sea?

Earth's first life form may have developed between the layers of a chunk of mica sitting like a multilayered sandwich in primordial waters, according to a new hypothesis. The mica hypothesis, which was...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA