A circumplanetary disk was sighted by a group of astronomers through the Atacama Large Millimeter / submillimeter Array (ALMA). This is the first time, according to the same researchers, that a disk of planetary material is identified by optical light, composed mainly of dust and gases which are the remnants of the formation of a planet.
The disk has been identified around PDS 70 c, a planet that orbits PDS 70, a young star that is at a distance of 370 light-years from us. PDS 70 c is an external planet that is at a distance from its star similar to the distance between Neptune and the Sun.
This planet had already been identified along with another gaseous planet, PDS 70 b, which is located at a distance from its star similar to that which separates Uranus from the Sun and which presents a mass of dust that resembles a tail.
“For the first time, we can definitely see the telltale signs of a circumplanetary disk, which helps support many of the current theories on planet formation,” explains Andrea Isella, a researcher at Rice University in Houston and one of the authors of the study. The astronomer thinks that the material that circulates around this planet, formed relatively recently, is favoring the formation of moons of planetary dimensions.
The identification at the level of optical light of the disk around PDS 70 c was possible thanks to ALMA which analyzed in particular millimeter and submillimetre wavelengths, wavelengths at which the stars emit relatively little light and are therefore not in able to completely hide planets and elements that revolve around them, with their brightness.
The chlorophyll photosynthesis implemented by plants began on Earth, according to various tests, already 3 billion years ago. However, oxygenation of the atmosphere seems to have occurred much later than the beginning of photosynthesis by plants, a process that in itself releases oxygen.
This is an enigma that geologists have not been able to solve, as recalled by Christopher Reinhard, a researcher at the Georgia Institute of Technology who, through a new study, conducted together with researcher Kazumi Ozaki and other colleagues, has tried to clarify the question a bit.
The researchers say they have discovered “that photosynthetic bacteria that use iron instead of water are fierce competitors for light and nutrients,” says Ozaki himself, now a researcher at the University of Toho, Japan.
This means that in the oceans of the primordial Earth the photosynthesizers that release oxygen could not effectively compete with their more primitive counterparts, ie those that consumed dissolved iron ions, very abundant elements on the primordial Earth.
These counterparts produced rust as a by-product instead of oxygen. For a long time, therefore, these photosynthesizers were able to overcome the photosynthesizers that produced oxygen.
The study was published in Nature Communications where it is available in complete form.
A new drone with two propellers and with what is defined as an “advanced stabilization system” was developed by a group of engineers from Flybotix, a start-up of the Ecole Polytechnique Federale de Lausanne (EPFL).
According to the EPFL press release, this drone can boast better autonomy as it can fly twice as long as classic models. It is also smaller in size, always compared to the average, and this means that it can also be used in those cases where it is necessary to inspect cavities or areas that are difficult to reach, such as those in industrial plants.
This new drone would, therefore, resolve what is considered the main defect of today’s drones, or the low battery autonomy. The drone created by Samir Bouabdallah and colleagues, can count on a new propulsion system that mimics that of helicopters. Thanks to this system it can only use two propellers and this already reduces battery consumption.
The engineers then added a special stabilization based on algorithms that provide better aerodynamic performance, once again similar to those of a helicopter.
The new stabilization system is necessary: a drone with only two propellers is less stable and more difficult to manipulate than a quadcopter, ie a drone with four propellers. The stabilization was obtained through a particular ring structure with the propellers which, stacked one above the other in the center, turn in a different direction.