Yutu-2 has been a busy roamer . Carried by theChang’E-4 landerto the far side of the Moon in January 2019 , it has moved further across the lunar surface than any other rover , collecting a variety of measurements . Now , for the first time , it has peer underneath the lunar aerofoil down to 300 meters ( 1,000 foot ) , deep than ever before , give away some interesting surprise .

The Lunar Penetrating Radar ( LPR ) has two TV channel that can reach unlike depth depending on the frequence used . The radar sends receiving set waves down into the ground and collects the echoes . dissimilar material produce different Echo . The low - oftenness one can riddle profoundly inside the Moon , while the higher frequency reveals more details of what lie just underneath the lunar open soil , the regolith .

In 2020 , the Yutu-2 team used the LPR tomap the upper 40 meters(130 base ) but now it has provided a more elaborate look at the top 300 meter ( 1,000 feet ) of the lunar control surface along the rover ’s itinerary . Five different layers of material have been identified below 90 meters of depth ( nearly 300 feet ) . The thickness of each level is quite varying , ranging from 70 metre to just 20 ( 230 to 66 fundament ) . The thickheaded layers are quite significantly the deep .

The team believes this tells us something about past volcanism on the Moon . Our born satellite was once very geologically active with lava flowing on its control surface . The Maria , the seas of the Moon , are big basalt plains create by volcanic activity as was the Von Kármán volcanic crater in the South Pole - Aitken Basin , where Chang’E-4 landed .

The datum is ordered with a series of basalt eruptions that took place billions of years ago . The team thinks that the diminution in thickness mean that the lava outburst rate decreased after each subsequent blast . This is reproducible with the general horizon of volcanism on the Moon . As our satellite aged and cooled , volcanism became rarer and rarer .

The observation with the mellow - frequency radar mostly focused on the top 40 meters . That part was mostly rock debris and regolith but reveal several layers too . And not just that : a buried volcanic crater was seen among the rubble . The Moon might be slow in neuter its geology without an atmosphere and flowing pee , but things do change .

The discipline was published inJGR Planets .