Gizmorama - May 2, 2018
Water is definitely a survivor. According to scientists, water can even survive asteroid impacts. The second story details this amazing scientific discovery.
Learn about this and more interesting stories from the scientific community in today's issue.
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*-- Scientists observe nanomaterial formation in 4D --*
Material scientists at Northwestern University have designed a transmission electron microscope, or TEM, to capture high-resolution, multi-frame videos of nanoparticles.
The technology allowed researchers to analyze nanomaterial formation across space and time -- in four dimensions. The researchers' breakthrough, detailed this week in the journal ACS Central Science, could pave the way for innovations in the design and synthesis of drugs, paints, coatings, lubricants and other advanced materials.
"We have demonstrated that TEM does not have to be a microscopy method solely used to analyze what happened after the fact -- after a reaction ends," Nathan Gianneschi, professor of chemistry, materials science and engineering at Northwestern, said in a news release. "But, rather, that it can be used to visualize reactions while they are occurring."
Until now, scientists could only capture snapshots of nanoparticles, limiting their ability to understand their formation.
"Now, we are beginning to see the evolution of materals in real time, so we can see how transformations occur," said Brent Sumerlin, a professor of chemistry at the University of Florida. "It's mind blowing."
In the lab, Sumerlin regularly uses a technique called polymerization-induced self-assembly, or PISA, to create a type of nanomaterial called micelles, which have a variety of functions.
To better understand how micelles actually form, Sumerlin and his colleagues integrated PISA with TEM, using the microscope's laser to trigger the reaction that begins the self-assembly process. The microscope's camera system wasn't able to capture the transformation in its entirety, but it did observe a larger portion of it.
"I'm pleasantly surprised that we pulled this part off," Gianneschi said. "But optimizing the system -- so we can see the reaction's entire trajectory -- will keep us busy for the next few years."
*-- Projectile cannon tests show how water can survive asteroid impacts --*
Scientists have credited comets and asteroids with delivering water and other elements necessary for life to Earth shortly after the planet was formed. But impact models suggest water should be entirely boiled away by the heat generated by such a collision.
Brown University researchers used a high-powered projectile cannon to investigate the contradiction. The results of their experiments, detailed this week in the journal Science Advances, suggest surprising amounts of water can survive asteroid impacts.
"The origin and transportation of water and volatiles is one of the big questions in planetary science," Terik Daly, now a postdoctoral researcher at Johns Hopkins University, said in a news release. "These experiments reveal a mechanism by which asteroids could deliver water to moons, planets and other asteroids. It's a process that started while the solar system was forming and continues to operate today."
Originally, scientists thought icy comets supplied most of the water found on Earth, but isotopic analysis suggests Earth's early water supply was most similar to water found trapped in carbonaceous asteroids.
How exactly water would survive a rock-on-rock collision, however, has remained a mystery. Computer models suggest all water would be completely vaporized during such a collision.
"But nature has a tendency to be more interesting than our models, which is why we need to do experiments," said Pete Schultz, professor of planetary science at Brown.
Schultz, Daly and their colleagues built miniature asteroid models based on the composition of carbonaceous chondrites, the remains of water-rich asteroid fragments that struck Earth long ago. The research team loaded the mini asteroids into the Vertical Gun Range at the NASA Ames Research Center and shot them into a compacted wall of pumice powder at speeds of approximately 11,000 miles per hour.
Scientists replicated impacts featuring speeds and angles common throughout the solar system. They found as much as 30 percent of the original water content remained trapped in the fragments that survived the collisions.
Though almost all of the water is vaporized, some of that vapor gets trapped in a plume of impact material and reincorporated into debris as melted rocks cool into solid fragments.
"The impact melt and breccias are forming inside that plume," Schultz said. "What we're suggesting is that the water vapor gets ingested into the melts and breccias as they form. So even though the impactor loses its water, some of it is recaptured as the melt rapidly quenches."
The research could not only help explain water on early Earth, but also more recent signs of water on the moon and the planetary bodies.
"The point is that this gives us a mechanism for how water can stick around after these asteroid impacts," Schultz said. "And it shows why experiments are so important because this is something that models have missed."
Earlier this year, researchers in Russia blasted miniature asteroid models with a high-powered laser to better understand the kinds of forces needed to destroy a space rock headed for planet Earth.
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