When celestial bodies became cosmic bombs: In the October issue, bild der Wissenschaft presents new findings on the collisions in the solar system and how they shaped the earth. The focus is on the giant impact hypothesis, the so-called late heavy bombardment and two impact craters on German soil.
At first a loose disc of matter circled around our young sun, then the material clumped together to form larger and larger structures, until the planets and moons emerged. To put it simply, the large structures of our cosmic home system were formed in this way. But the process also left a myriad of smaller and larger debris: planetoids and comets buzz through the solar system and can change their orbits again and again when they collide with one another. So they can get on a collision course with the planets and moons. This resulted in many collisions, especially among the youth of our solar system. But there are still many potential impactors in space, as the traces of devastating impacts in recent geological history show.
In the first article of the three-part title topic, the bdw author Thorsten Dambeck focuses on two such geologically young craters in southern Germany: the Nördlinger Ries and the smaller Steinheimer basin. The two impact scars are not far apart and formed about 15 million years ago. So far it has been assumed that a celestial body and its little moon crashed into the region at that time. But as Dambeck reports in the article “Inferno in Germany’s Primeval Times”, there are also indications that there were two independent impact events that once devastated the region.
Bangs in the history of the earth
Dambeck then takes a deeper look into the history of the earth and deals with a bombastic event of far greater dimensions: Today it is assumed that the earth collided with another planet shortly after its formation. According to the so-called giant impact hypothesis, our moon emerged from the rubble. Theia has become the name of the collision partner. In the article “Theia, desperately wanted”, the author reports on results, according to which this planet was significantly larger than previously assumed. Isotope analyzes also suggest the origin of Theia. Perhaps parts of the mysterious celestial body are still slumbering deep inside the earth, according to the article.
Finally Dambeck deals with the extent and the temporal course of the cosmic bombardment in the early history of the earth. There are indications that around four billion years ago there was a phase with a particularly high number of impacts on the moon and earth. This era is known as “Late Heavy Bombardment”. But as the author reports, doubts about the previous assumptions are increasing: Did a flood of cosmic impacts actually occur when the first life on earth was stirring? The article also deals with the possible cause of the increased hail of bombs. According to new findings, it is questionable whether changes in the orbits of Jupiter and Saturn triggered the impacts.
The cover topic “Cosmic Collisions” can be found in the October issue of bild der Wissenschaft, which will be available in stores from September 21, 2021.