Ductile fracture. The propagation of a ductile crack involves substantial plastic flow and ductile fracture usually gives a characteristic rough fracture surface.Fracture occurs by a process known as microvoid coalescence. First, plastic strain causes small microvoids to form in the material, most often at sites of inclusions.he propagation of a ductile crack involves substantial plastic flow and ductile fracture usually gives a characteristic rough fracture surface.
An illustration of the space-time curvature caused by Earth. Space-time is a mathematical model that joins space and time into a single idea called a continuum. This four-dimensional continuum is known as Minkowski space. Combining these two ideas helped cosmology to understand how the universe works on the big level (e.g. galaxies) and small level (e.g. atoms).
Time is an abstract concept, it only exists in our heads. Time is measured by the oscillations of the Cesium 133 atom, 9,192,631,770 oscillations last 1 second in duration. Time can be different for different observers, relative to your motion is space. Time coupled with space can also be said to be a manifestation of the curvature of space caused by gravity.