Issued back in 1963, this set of 10 mint stamps depicts various satellites and space craft sent up by the Soviet space program.
Many solids can dissolve in liquids like water, and while this is often treated as a matter of chemistry, fluid dynamics can play a role as well. As seen in this video by Beauty of Science, the dissolving candy coating of an M&M spreads outward from the candy. This is likely surface-tension-driven; as the coating dissolves, it changes the surface tension near the candy and flow starts moving away thanks to the Marangoni effect. With multiple candies dissolving near one another, these outward flows interfere and create more complex flow patterns.
These flows directly affect the dissolving process by altering flow near the candy surface, which may increase the rate of dissolution by scouring away loose coating. They can also change the concentration of dissolved coating in different areas, which then feeds back to the flow by changing the surface tension gradient. (Video and image credit: Beauty of Science)
Via MIT Tech Review:
… results show that it was difficult to get any human cells to survive in pig embryos and contribute to a developing fetus. Their best effort resulted in only a minimal number of human cells. It’s likely that the larger genetic distance between pigs and man is to blame.
From the Luna 2 in 1959 to the DSCOVR in 2015, this color-coded chart traces the trajectories of every orbiter, lander, rover, flyby, and impactor to ever slip the surly bonds of Earth’s orbit and successfully complete its mission – a truly astronomical array of over 100 exploratory instruments in all. Featuring hand-illustrated renderings of each spacecraft juxtaposed against the serried giants of our solar system, this galactic survey is a testament to man’s forays into the grand cosmic ballet. [via]