United States researchers prepare to study an 18-mm hypersonic projectile striking water
Researchers in the United States are planning to document a tiny yet incredibly fast projectile that travels at about 14,500 kilometers per hour as it enters a large body of water. The effort is being coordinated by a major university research program and aims to observe how water responds to extreme impact at hypersonic speeds. The project is a high-profile step in assessing how ultra-fast objects interact with liquids and what unusual phenomena might arise when striking a liquid surface at such velocity.
At these extreme speeds, both solids and liquids can exhibit unusual behavior. A senior engineering scientist notes that even as of the early 2020s there remains uncertainty about the precise changes that water undergoes in these events. There is evidence to suggest the possibility of remarkable outcomes, from rapid ice formation to unexpected light emissions, though the exact sequence of events is still being studied. This uncertainty has drawn interest from the scientific community that studies high-speed impacts and fluid dynamics. Researchers emphasize that the understanding gained from these experiments could inform a variety of applications, from material science to defense technology and safety protocols in matched conditions.
For the experiment, a 12-meter device typically used to simulate meteorite-like impacts will be deployed in a controlled water tank. The facility features a water depth greater than nine meters to accommodate the spreading effects of the collision and to capture the full complexity of the interaction. The event will be recorded with a high-speed camera capable of streaming up to 200 million frames per second, allowing scientists to analyze the rapid processes in painstaking detail. This approach ensures that every nanosecond of the impact is visible for study, providing a window into phenomena that occur almost instantaneously in real time.
From a theoretical standpoint, three effects have been anticipated: the formation of ice within the impacted zone, cavitation, and sonoluminescence. The concept of exotic ice arising from intense interactions between liquid water and high-energy impulses was proposed in the mid-20th century as physicists explored shock-driven phase changes. Cavitation involves the creation of vapor bubbles in a liquid as it accelerates toward high speeds, which can then collapse and release energy in localized regions. A researcher notes the likelihood of observing cavitation in the wake of the projectile as it passes through the water. Sonoluminescence refers to light emitted by a liquid when subjected to rapid pressure variations, a phenomenon that has fascinated scientists for decades as they investigate how sound waves can trigger luminescent events in liquids.
At first glance, an 18-mm projectile moving at 14,500 kilometers per hour would be categorized as hypersonic within air. However, sound travels faster in water than in air, so the collision in a liquid environment is technically supersonic. The research program anticipates that findings will contribute to a deeper understanding of fluid dynamics under extreme conditions and will resonate with ongoing efforts in hypersonic technology development in the United States. The experiment is planned for the summer of 2023 and serves as part of a broader exploration of how fast-moving bodies interact with liquids, with potential implications across both civilian and defense-related research agendas. Researchers involved in the project emphasize that their work is driven by curiosity about the fundamental physics of high-speed impacts and by the practical value of understanding how materials and liquids respond under such intense stress. The project is supported by institutions focused on advancing knowledge in aerospace engineering, materials science, and fluid mechanics, with findings slated for dissemination through peer-reviewed scientific channels and institutional reports. Attributable insights will likely enrich the scientific literature on shock physics, multiphase flow, and high-speed hydrodynamics, as researchers seek to map the range of possible outcomes under controlled, ethically conducted experiments.