Lifeboat Foundation

With simulations that go into finer details than ever before, Brooke Polak of the University of Heidelberg and Hubert Klahr at the Max Planck Institute for Astronomy (MPIA) have modeled a key phase in the formation of planets in our solar system: the way that centimeter-size pebbles aggregate into so-called planetesimals tens to hundreds kilometers in size. The simulation reproduces the initial size distribution of planetesimals, which can be checked against observations of present-day asteroids. It also predicts the prevalence of close binary planetesimals in our solar system.

In a new study published on arXiv and accepted for publication in The Astrophysical Journal, astrophysicists Brooke Polak from the University of Heidelberg and Hubert Klahr from the Max Planck Institute for Astronomy used simulations to derive key properties of so-called planetesimals—the intermediate-size bodies from which planets formed in our solar system roughly 4.5 billion years ago.

Using an innovative method for simulating planetesimal formation, the two researchers were able to predict the initial size distribution of planetesimals in our solar system: how many are likely to have formed in the different “size brackets” between roughly 10 km and 200 km.

An international team of space scientists reports that the moon exerts a tidal impact on the plasmasphere. For their paper published in the journal Nature Physics, the group used data from multiple spacecraft over a nearly 40-year period to measure tidal perturbations in the plasmapause. Balázs Heilig, with the Institute of Earth Physics and Space Science, in Hungary, has published a News & Views piece in the same journal issue, explaining the nature of the plasmasphere and outlining the work in this new effort.

Early scientists found a connection between the tides and the movement of the moon thousands of years ago. More recent evidence suggests the moon’s pull acts on the ionosphere as well. In this new study, the researchers wondered if the moon might also have an impact on the plasmasphere.

The plasmasphere is a toroidal mass of plasma that surrounds the Earth. It lies beyond the ionosphere and is made up mostly of electrons and protons. Its particles are charged by the ionosphere, and its outer boundary is known as the plasmapause.

On Jan. 16, 2003 space shuttle Columbia left Earth for its 28th and last flight. Even though at the time building the International Space Station was the main goal of the shuttle program, STS-107 (Columbia’s final mission) emphasized pure research, according to Space.com.

The seven-member crew — Rick Husband, commander; Michael Anderson, payload commander; David Brown, mission specialist; Kalpana Chawla, mission specialist; Laurel Clark, mission specialist; William McCool, pilot; and Ilan Ramon, payload specialist from the Israeli Space Agency — had spent 24 hours a day doing science experiments in two shifts.

The seven astronauts on board Columbia were killed on Feb. 1, 2003 when the space shuttle broke up while it was returning to Earth.

JWST is good at spotting very faint, very distant objects like ancient galaxies, because it views the universe in infrared light, whose wavelengths are slightly longer than the ones our unaided eyes can see. Light from distant objects, which are moving even farther away from us as the universe expands, gets stretched into those longer wavelengths.

Although this is the most recent image the JWST team has processed and released to the public, it was one of the first images the telescope actually took. During the early summer of 2022, astronomers and engineers were firing up Webb’s instruments and getting them ready to do real science observations. This stunning image of spiral galaxy LEDA 2,046,648 was part of the process of commissioning JWST’s Near-Infrared Imager and Slitless Spectrograph (which was recently out of order for two weeks thanks to a run-in with a cosmic ray).

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‘Spin’ is a fundamental quality of fundamental particles like the electron, invoking images of a tiny sphere revolving rapidly on its axis like a planet in a shrunken solar system.

Only it isn’t. It can’t. For one thing, electrons aren’t spheres of matter but points described by the mathematics of probability.

But California Institute of Technology philosopher of physics Charles T. Sebens argues such a particle-based approach to one of the most accurate theories in physics might be misleading us.

The dynamics of electrons submitted to voltage pulses in a thin semiconductor layer is investigated using a kinetic approach based on the solution of the electron Boltzmann equation using particle-in-cell/Monte Carlo collision simulations. The results showed that due to the fairly high plasma density, oscillations emerge from a highly nonlinear interaction between the space-charge field and the electrons. The voltage pulse excites electron waves with dynamics and phase-space trajectories that depend on the doping level. High-amplitude oscillations take place during the relaxation phase and are subsequently damped over time-scales in the range 100 – 400 fs and decrease with the doping level. The power spectra of these oscillations show a high-energy band and a low-energy peak that were attributed to bounded plasma resonances and to a sheath effect. The high-energy THz domain reduces to sharp and well-defined peaks for the high doping case. The radiative power that would be emitted by the thin semiconductor layer strongly depends on the competition between damping and radiative decay in the electron dynamics. Simulations showed that higher doping level favor enhanced magnitude and much slower damping for the high-frequency current, which would strongly enhance the emitted level of THz radiation.

Since the focus on Martian exploration ramped up in the mid-1990s, most of the familiarity with the Entry, Descent, and Landing (EDL) sequence of landers and rovers to the surface of other planets has taken place against the backdrop of Mars.

But when NASA‘s upcoming Dragonfly mission arrives at Titan for its own EDL, it will experience a starkly different set of conditions that both add new complexity and ease some structural considerations for the system that will deliver the rotorcraft into Titan’s atmosphere.

Year 2022, this basically could shield the earth or Mars from solar radiation if we needed it. 😗

First experimental measurement of pure electron outflows associated with magnetic reconnection driven by electron dynamics in laser-produced plasmas.

Magnetic reconnections in laser-produced plasmas have been investigated in order to better understand the microscopic electron dynamics, which are relevant to space and astrophysical phenomena. Osaka University scientists, in collaboration with researchers at the National Institute for Fusion Science and other universities, have reported the direct measurements of pure electron outflows relevant to magnetic reconnection using a high-power laser, Gekko XII, at the Institute of Laser Engineering, Osaka University in Japan. Their findings will be published today (June 30, 2022) in Springer Nature, Scientific Reports.

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