Tiny telescope finds a new kind of variable star
A team from Switzerlands Geneva Observatory has discovered a new class of variable stars by measuring minute variations in stellar brightness. They achieved this precision using a comparatively small (3.9-foot) telescope for an observing program over seven years. The results are based on regular measurements of the brightness of more than three thousand stars in open star cluster NGC 3766 in the constellation Centaurus.
Many stars are known as variable or pulsating stars because their apparent brightness changes over time. How the brightness changes depends in complex ways on the properties of star interiors. This phenomenon has allowed the development of asteroseismology, where astronomers can listen to these stellar vibrations, in order to probe the physical properties of the stars and get to know more about their inner workings.
The very existence of this new class of variable stars is a challenge to astrophysicists, said team member Sophie Saesen. Current theoretical models predict that their light is not supposed to vary periodically at all. ESO.org
Discovery may control growth, ripening of produce
Its common wisdom that one rotten apple in a barrel spoils all the other apples, and that an apple ripens a green banana if they are put together in a paper bag. Now the genes underlying these phenomena have been revealed.
In the online journal eLIFE, an international group of scientists led by investigators at the Salk Institute for Biological Studies, in San Diego, have traced the thousands of genes in a plant that are activated once ethylene a gas that acts as a plant growth hormone is released.
This study, a comprehensive genomic analysis of ethylenes biological trigger, may lead to powerful practical applications. Ethylene not only helps ripen fruit, it also regulates growth and helps defends a plant against pathogens, among a variety of other function.
Teasing out specific genes that perform each of these discrete functions, from the many genes found to be activated by ethylene, might allow scientists to produce plant strains that slow growth when needed, accelerate or prevent ripening, retard rotting or make plants more resistant to disease. Salk Institute
Plastics effectively shield radiation on moon
Space scientists from the University of New Hampshire and the Southwest Research Institute report that data gathered by NASAs Lunar Reconnaissance Orbiter (LRO) show lighter materials like plastics provide effective shielding against the radiation hazards faced by astronauts during extended space travel. The finding could help reduce health risks to humans on future missions into deep space.
Aluminum has always been the primary material in spacecraft construction, but it provides relatively little protection against high-energy cosmic rays and can add so much mass to spacecraft that they become cost-prohibitive to launch.
This is the first study using observations from space to confirm what has been thought for some time that plastics and other lightweight materials are pound-for-pound more effective for shielding against cosmic radiation than aluminum, said lead author Cary Zeitlin.
The scientists published their findings in Space Weather, an online American Geophysical Union journal. UNH.edu