Demystifying the internal structure of Mars

  The National Aeronautics and Space Administration (NASA) released the first detailed map of the internal structure of Mars based on the Martian vibration data collected by the InSight Mars rover, showing that the internal structure of Mars is very different from that of the Earth. The crust of the southern highlands of Mars is thicker, while the crust of the northern lowlands is thinner. Scientists speculate that there may have been oceans here a long time ago. The average thickness of the Martian crust is between 24 and 72 kilometers. The Martian crust may have three layers: upper, middle, and lower. The upper layer is mainly volcanic rock crushed by meteorites, the middle layer is more coherent volcanic rock, and the structural characteristics of the lower layer are not yet known. Like the Earth, the Martian mantle is much thicker than the outer shell. The upper mantle is a hard and dense rock, and it is also the basis of the ever-changing tectonic plates on the earth. In contrast, the upper Martian mantle may be twice as thick as the upper mantle, or even thicker. As a result, Mars does not have as many tectonic plates as the Earth, nor does it form mountains, canyons, basins, plains, and oceans. Kind of landform features. At the same time, the overall thickness of the Martian mantle is about half that of the mantle, causing the Martian heat to dissipate, rapid cooling, and the disappearance of the magnetic field.

Birds also have a sense of smell

  Although it has been found that some birds, such as vultures, hunt by smell, it is generally believed that most birds have little sense of smell. In 2008, German scientists analyzed the genomes of 9 bird species involving 7 orders and discovered many olfactory receptor genes. Olfactory receptors are special proteins that can bind to odor molecules. They are responsible for “reporting” odor-related signals to the brain. The more receptor genes that animals have, the stronger their sense of smell. For example, mice have nearly 1,000 active olfactory receptor genes, and humans carry about 400 such genes. There are as few as more than 100 birds and as many as more than 600 functional olfactory receptor genes. Recently, American scientists have discovered many new olfactory receptors on this basis. Especially found in a very ancient bird, the emu, that the sense of smell may have been vital to birds from the beginning.
Dinosaurs once “settled” in the Arctic

  In the 1950s, people accidentally discovered the remains of dinosaurs in the cold polar regions. Now, researchers have found the first convincing evidence that several dinosaurs not only wandered in northern Alaska, but also nested there. The dinosaurs discovered by the researchers in the Arctic included herbivorous dinosaurs of various sizes, such as hadrosaurus, ceratosaurus, and stegosaurus; and carnivorous dinosaurs, such as Tyrannosaurus, Tetraodontosaurus, and Velociraptor; many of them Small dinosaur fossils, even individuals that are still in dinosaur eggs or have just hatched. These findings further prove that dinosaurs can not only live in extremely high latitudes, but are likely to live there all year round. At present, no traces of cold-blooded terrestrial vertebrates such as amphibians, lizards and crocodiles have been found in the polar regions. Only birds, mammals and dinosaurs live here, which also provides evidence that dinosaurs are warm-blooded animals.