NASA Parody Videos

For something fun for you today, I thought I'd give you the gift of humor thanks to the great folks at NASA.

Raindrops Landing in Sand Behave the Same as Asteroid Impacts

Asteroid impacts occur much more often than most people think, but a much more common phenomenon produces the same devastating impact on a much smaller scale. According to a new study from the University of Minnesota, water droplets landing on a granular surface, or raindrops landing on the beach for example, produce the same type of crater impact as an asteroid. 

The authors stated in the abstract: "Surprisingly, we found that liquid-drop impact cratering follows the same energy scaling and reproduces the same crater morphology as that of catastrophic asteroid impact cratering."

The researchers demonstrated this effect in a slow motion video, which won the 2014 APS Physics Fluid Motion Award.

In the above video, the water droplet lands on the sand at 1 m/s and creates a large crater that looks very much like the aftermath of an asteroid impact. But the most visually interesting part might come after the impact, when the droplet rises above the crater in a perfect, sand-covered sphere before oozing back down into the center of the crater. This all occurs over the course of 80.9 milliseconds.

 

[Credit: University of Minnesota]

They then demonstrated the effect with higher velocity impact, first 3.3 m/s and then 5.4 m/s. In the former case, the water droplet seems to become completely dispersed, and then appears to reassemble back into a droplet. But in the latter case, the velocity is high enough that the droplet just disintegrates upon impact:

 

[Credit: University of Minnesota]

 

[Credit: University of Minnesota]