What's Up? The Space Place

Hey Space Placers! A just published article states that the Earth had 70 asteroid impact hits on the level o,f or even larger than, the dinosaur killing impact event 65 million years ago. This is a significant increase in the number of "mega-hits" the Earth was thought to have endured  1.8 to 3.8 billion years ago. The Moon is thought to have been hit 4 times with the same size impactors. The research was based on findings in Australian rock samples and computer studies. As stated by NASA: "Evidence for these impacts on Earth comes from thin rock layers that contain debris of nearly spherical, sand-sized droplets called spherules. These millimeter-scale clues were formerly molten droplets ejected into space within the huge plumes created by mega-impacts on Earth. The hardened droplets then fell back to Earth, creating thin but widespread sedimentary layers known as spherule beds. The new findings are published today in the journal Nature ." “The beds speak to...

Hey Space Placers! Continuing our impact related theme of the past two days, a new discovery has been made on Mars that incoming meteors large enough to create craters are also causing dust avalanches. The avalanches are caused by the shockwave that precedes the incoming impactor which is traveling at several times the speed of sound. Because the Martian atmosphere is not as dense as Earth's, a lot of meteors that would burn up in our atmosphere survive on Mars to create new craters. From the University of Arizona Press Release, "Each year, about 20 fresh craters between 1 and 50 meters (3 to 165  feet) show up in images taken by the HiRISE camera on board NASA’s  Mars Reconnaissance Orbiter. The High Resolution Imaging Science  Experiment, or HiRISE, is operated by the UA’s Lunar and Planetary  Laboratory and has been photographing the Martian surface since 2006,  revealing features down to less than 1 meter in size.  For this study, the team zo...