impact craters tagged posts

Ground-penetrating radar from China’s Martian rover Zhurong reveals shallow impact craters and other geologic structures in the top five meters of the Red Planet’s surface. The images of the Martian subsurface are presented in a paper published in Geology.

The Zhurong rover was sent to Mars as part of China’s Tianwen-1 mission. Launched in July 2020, the rover landed on the surface on 15 May 2021. The rover was sent to a large plain in the northern hemisphere of Mars named Utopia Planitia, near the boundary between the lowlands where it landed and highlands to the south.

The region was chosen because it’s near suspected a...

Valley networks on Mars show evidence for surface runoff driven by rainfall. Credit: Image courtesy of Elsevier

New study reveals how changes in Martian rainfall shaped the planet. Heavy rain on Mars reshaped the planet’s impact craters and carved out river-like channels in its surface billions of years ago. Changes in the atmosphere on Mars made it rain harder and harder, which had a similar effect on the planet’s surface as we see on Earth. Mars has geological features like the Earth and moon, eg. craters and valleys, many of which were formed through rainfall. Although there is evidence that there was once water on Mars, it does not rain there today.

But in their new study, geologists Dr. Robert Craddock and Dr...

A thankfully rare event: an asteroid hits the Earth. (Visualisations: iStock / Solarseven)

Do mass extinctions, like the fall of the dinosaurs, and formation of large impact craters on Earth occur together at regular intervals? “This question has been under discussion for more than 30 years now,” says Matthias Meier, ETH Zurich’s Institute of Geochemistry and Petrology. As late as 2015, US researchers indicated that impact craters were formed on Earth around every 26 million years. “We have determined, however, that asteroids don’t hit the Earth at periodic intervals,” says Meier, refuting the popular hypothesis.

In the past, researchers have even postulated the existence of a companion star to the Sun...

Ritchey Crater, located near the Martian equator, has impact melt deposits containing clay minerals. Impact melt forms when rock melted during an impact cools and hardens. The clay minerals found within these deposits are very likely to have formed after the impact event. Most clay minerals on Mars are thought to have formed during the earliest Martian epoch, known as the Noachian. However, evidence from Ritchey crater and other post-Noachian craters, suggests that clay formation after the Noachian was not uncommon. Credit: NASA/JPL/University of Arizona/Brown University

Clays and other minerals formed when rocks are altered by water have been found in multiple locations on Mars. It’s been assumed that these minerals probably formed in the earliest Martian epoch, >3.7B yrs ago...