In physics, acceleration is defined as the rate of change of velocity (or speed). For example, if we drop a ball from our hand, it has an acceleration of about 9.81m/s² (also known as 1-g), which means it will have a speed of 9.81 m/s after the first second, 2x9.81=19.62 m/s after two seconds, and so on. We humans can endure accelerations of upto 5-10g.

Z Machine (Courtesy: LiveScience)Scientists at the Sandia National Labs in Albuquerque, New Mexico have accelerated a small plate from zero to 76,000 mph (34 km per second) in less than a second, which is equivalent to 10¹⁰g!! In contrast, the Earth travels at a speed of 30 km per second around the Sun. This is 50 times faster than the fastest bullet, and 10 times faster than the International Space Station:):).
The ultra-tiny aluminum plates are just 850 microns (1 micron = 1/1000th of a millimeter) thick. Z’s hurled plates strike a target after traveling only five millimeters, or less than a quarter-inch. The impact generates a shock wave - in some cases, reaching 15 million times atmospheric pressure - that passes through the target material. The waves are so powerful that they turn solids into liquids, liquids into gases, and gases into plasmas in the same way that heat melts ice to water or boils water into steam.
One purpose of these very rapid flights is to help understand the extreme conditions found within the interiors of giant planets in our solar system. By creating states of matter extremely difficult to achieve on Earth, the flyer plates provide hard data to astrophysicists speculating on the structure and even the formation of planets like Jupiter and Saturn.
Later this year and next, more experiments are planned, that will push towards higher and higher velocities:):).