Tuesday, April 23, 2019

Potential for Life On Other Planets In Milky Way Revealed in New Study

One of the conditions for the emergence and persistence of life on Earth is the existence of geological activity such as earthquakes and volcanoes.

Volcanic activity caused by the movement of tectonic plates over the mantle (plate tectonics) recycles gases such as carbon dioxide through the mantle, crust, atmosphere and oceans, helping to keep the planet habitable by maintaining temperatures at ideal levels for the survival of living beings, scientists explain.

A study conducted by Brazil’s National Space Research Institute (INPE) suggests our galaxy, the Milky Way, contains other rocky planets with a high probability of having plate tectonics, increasing the chances that they are habitable.

Researchers have found evidence of the existence of rocky exoplanets with a high probability of having plate tectonics, increasing the likelihood that they are habitable 

Credit: R. Hurt / NASA

The study was supported by FAPESP. The results have been published in Monthly Notices of the Royal Astronomical Society (MNRAS).

“We found that geological conditions favorable to the emergence and maintenance of life exist on rocky planets, that life may exist throughout the Milky Way and that it may have originated at any time during our galaxy’s evolution,” said Jorge Luis Melendez Moreno, a professor at the University of São Paulo’s Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG-USP) in Brazil and one of the authors of the study.

Scientists at other research institutions in Brazil and abroad also participated in the study.

They determined the surface parameters, masses and ages of 53 solar twins located at different points in the Milky Way. They also analyzed the chemical composition of these stars, called solar twins because their temperature, gravity and surface chemistry are similar to those of our Sun. The aim of the study was to discover whether potentially habitable rocky planets also orbit around the stars in question.

The analysis was performed using a spectrograph called HARPS (High Accuracy Radial velocity Planet Searcher) installed on the 3.6 m telescope operated by the European Southern Observatory (ESO) at the La Silla facility in Chile. The instrument measures the electromagnetic spectra of the “colors” emitted by celestial bodies, from shorter (ultraviolet) to longer (infrared) wavelengths.

The findings showed that the stars contain an abundance of thorium, a radioactive element with isotopes that split owing to atomic instability into smaller isotopes, emitting energy in a process called radioactive decay.

The energy released by the decay of unstable isotopes – not only thorium but also other radioactive elements such as uranium and potassium – gives rise to Earth’s mantle convection and tectonic activity. Part of the planet’s internal heat is a remnant of the primordial heat from its formation, but at least half is due to radioactive energy.

Thus, the initial levels of these radioactive elements in a rocky exoplanet contribute indirectly to the habitability of its surface, especially given the long time they take to decay, on the scale of billions of years, the researchers explained.

“The thorium levels we measured in these solar twins point to a sufficient amount of available energy from the decay of this radioactive element to maintain mantle convection and plate tectonics in any rocky planets that may be orbiting around them,” said Rafael Botelho, first author of the study. Botelho is studying for a PhD in astrophysics at INPE.

The initial thorium abundances in the solar twins were compared with the abundances of iron, silicon (an indicator of mantle thickness and mass in rocky planets) and two other heavy elements, neodymium and europium. The results showed that the thorium-silicon ratio in the solar twins increased over time and was equal to or higher than that of our Sun since the formation of the Milky Way.

“There are signs that thorium is also abundant in old solar twins. This means the Milky Way’s disk could be full of life,” said André Milone, a scientist at INPE and supervisor of Botelho’s PhD research.

Contacts and sources:
By Elton Alisson
Agência FAPESP

Citation: “Thorium in solar twins: implications for habitability in rocky planets” by R. B. Botelho, A. de C. Milone, J. Melendez, M. Bedell, L. Spina, M. Asplund, L. dos Santos, J. L. Bean, I. Ramirez, D. Yong, S. Dreizler, A. Alves-Brito and J. Yana Galarza can be retrieved from: academic.oup.com/mnras/article-abstract/482/2/1690/5134163?redirectedFrom=fulltext.

Nanotechnology Clothing Controls Heat, Odor and Repels Insects

Functional fabrics that are due to be marketed next summer retain less heat, control body odor, protect against sunlight, and repel mosquitoes such as Aedes aegypti, which transmit pathogens that cause dengue, yellow fever, chikungunya and Zika.

Garments with this functionality use technology developed by Nanox Tecnologia S.A., a startup supported by FAPESP’s Innovative Research in Small Business Program (PIPE). The nanotechnology company is a spinoff from the Center for Research and Development of Functional Materials (CDMF), one of the Research, Innovation and Dissemination Centers (RIDCs) funded by FAPESP.

In partnership with textile manufacturers, Nanox is developing nanometric particles with different properties, such as controlling the microorganisms that produce body odor, reflecting electromagnetic radiation from the Sun, and releasing insect repellent in a controlled fashion.

Brazilian firm has developed nanoparticles that eliminate body odor, reflect solar radiation, and release insect repellent and insecticide in fabric 
Credit: Nanox

“We have a number of projects in progress with textile companies. Several are in the final stages of production of fabrics with these properties,” Daniel Minozzi told Agência FAPESP. Minozzi is Nanox’s co-founder and chief operating officer.

The nanoparticles developed by Nanox are made of different inorganic materials and can be added to fabric individually or in combinations to confer the desired properties. Body odor, for example, is controlled by bactericidal, antimicrobial and self-sterilizing nanoparticles containing silver, zinc and copper.

When the nanoparticles are added to fabric fibers, they protect the material against the bacteria, fungi and mites that cause unpleasant smells. They also prevent yellowing of the fabric, according to Nanox.

“One of the advantages of these antimicrobial nanoparticles over other chemicals added to commercially available anti-odor textiles is their enhanced resistance to washing, temperature and abrasion,” Minozzi said.

“They also have less environmental impact, and they’re anti-allergic, so they can be used in any type of fabric that comes into direct contact with skin, such as the material for regular clothing, sports apparel, underwear, bed sheets, towels, and military or security uniforms.”

Nanoparticles that protect against solar radiation and improve thermal comfort can be used in curtains, everyday garments, sportswear and beachwear, as well as apparel worn by workers exposed to sunlight for long periods.

The nanoparticles consist of hollow glass microspheres coated with a thin, transparent nanostructured film made of zinc oxide, aluminum or titanium. These nanostructured materials act as micromirrors that reflect infrared and ultraviolet light, blocking the light from penetrating the fabric. As a result, they are capable of reducing thermal transmittance (heat transfer to the fabric) by up to 65% at wavelengths of 500-4,000 nanometers.

The technology was developed as part of a project supported by FAPESP via PIPE.

In tests performed by Nanox, a fabric containing its customized nanoparticles and exposed to sunlight achieved a temperature reduction of 6.5 °C compared to the same fabric without the nanoparticles.

“The fabrics available today for protection against sunlight are only able to block ultraviolet rays,” Minozzi said. “The nanoparticles we’ve developed also reflect infrared rays, making the fabric cooler for use during the day. The technology is totally innovative.”

The firm’s nanoparticle technology for protection against flying and crawling insects represents an incremental innovation, he explained. Nanox does not disclose details of the technology for industrial secrecy reasons. However, it does say the innovation is in the system for containing repellent or insecticide molecules inside the nanoparticles and their fixation to the fabric.

“Some of the main issues currently complicating the addition of repellent to fabrics are repellent odor and postwash fixing. We’ve developed a system that overcomes these issues when insecticide or repellent is included to fabrics,” Minozzi said.

Bactericidal nanoparticles

The nanoparticles with bactericidal, antimicrobial and self-sterilizing properties developed by the firm are currently used in a range of products, including plastic utensils, PVC film for food wrapping, toilet seats, shoe insoles, hair dryers and flatirons, paints, resins, and ceramics, as well as coatings for medical and dental instruments such as grippers, drills and scalpels.

Today, the company’s largest markets are makers of white goods such as refrigerators, drinking fountains and air conditioners, as well as rugs and carpets.

“We’ve supplied the carpet and rug industry for eight years, so our effective entry into the textile segment now is a natural move,” Minozzi said.

Nanox currently exports via local distributors to Chile, China, Colombia, Italy, Mexico and Japan, among others, and recently opened a subsidiary in Boston (USA).

“We need a US branch to facilitate and accelerate the pursuit of a license to sell our product there. The licensing process is in the final stage of evaluation for approval,” Minozzi said.

Contacts and sources:
 Elton Alisson
Agência FAPESP