Although headquartered in Gothenburg, Sweden, the Volvo Group manufactures nearly all of its engines at factories in Skovde, Sweden; Hagerstown, MD; and Lyon, France. The Lyon facility produces various types and sizes of engines for Volvo and Renault trucks.
Like any technology, welding continues to evolve. This is especially true for a technique known as flash-butt welding, which has been around since the early 20th century.
Whether or not Earth is the only planet able to support life is debatable. What is undeniable, however, is that the planets of our solar system are not the only things that orbit the sun.