Visualization of regions of electromagnetic wave-plasma interactions surrounding the Earth

Researchers have investigated wave-particle interactions between energetic electrons and chorus waves evolving in the space surrounding the Earth using the scientific satellite Arase and, simultaneously, transient auroral flashes by the ground-based global observation network. The investigation visualized asymmetric spatial development of wave-particle interaction regions on the order of sub-seconds. This is expected to contribute to the safe and secure exploration of space by establishing hazard maps of the space electromagnetic environment.

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Image: “Schematic illustration of coordinated observation using the scientific satellite Arase and PWING, a ground-based observation network. Through detailed observation by the scientific satellite Arase in the magnetosphere and observation of aurorae along geomagnetic field lines from the ground, it is possible to investigate and capture the spatial distribution of generation regions of wave-particle interactions. Credit: (c) JAXA

Highly collimated jet spotted from the Red Square Nebula

Astronomers have detected a highly collimated, bipolar jet from the so-called Red Square Nebula (RSN) surrounding the B[e]-type star MWC 922. The newly discovered jet could reveal more insights into the nature of the RSN and its emission. The finding is detailed in a paper published January 24 on the arXiv pre-print repository.”

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Image:  The Red Square Nebula. Image credit: Peter Tuthill, Sydney University Physics Dept., and the Palomar and W.M. Keck observatories.

Giant impacts caused by interplanetary collisions

“Astronomers have found fresh evidence for significant planetary diversity within a single exoplanet system, suggesting that giant high-speed collisions are partly responsible for planetary evolution.

An international team of scientists led by Italy’s National Institute for Astrophysics (INAF) and involving physicists from the University of Bristol spent three years observing the exoplanetary system Kepler-107 via the Telescopio Nazionale Galileo in La Palma.

They gathered more than a hundred spectroscopic measurements of all four sub-Neptune mass planets in Kepler-107 – named after the NASA Kepler space telescope that discovered the exoplanetary system five years ago. Unlike Earth’s relation to the sun, the planets in the Kelper-107 system are much closer to each other and their host star (their equivalent of our sun). All of the planets have an orbital period of days as opposed to years.

It is not uncommon for the planet that is closest to the host star to be the densest due to heating and interaction with the host star which can cause atmosphere loss. However, as reported in Nature Astronomy, in the case of Kepler-107, the second planet, 107c, is denser than the first, 107b. So much so that 107c contains in its core an iron mass fraction at least twice as large as that of 107b, indicating that at some point, 107c had a head-on high-speed giant collision with a protoplanet of the same mass or more collisions with multiple planets of a lower mass. These impacts would have ripped off part of the rock and silicate mantle of Kepler-107c, suggesting that it is denser now than it was originally.


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Image: “One frame from the middle of a hydrodynamical simulation of a high-speed head-on collision between two 10 Earth-mass planets. The temperature range of the material is represented by four colours grey, orange, yellow and red, where grey is the coolest and red is the hottest. Such collisions eject a large amount of the silicate mantle material leaving a high-iron content, high-density remnant planet similar to the observed characteristics of Kepler-107c. Credit: Zoe Leinhardt and Thomas Denman, University of Bristol”

The Milky Way is warped

The Milky Way galaxy’s disk of stars is anything but stable and flat. Instead, it becomes increasingly warped and twisted far away from the Milky Way’s center, according to astronomers from National Astronomical Observatories of Chinese Academy of Sciences (NAOC).

From a great distance, the galaxy would look like a thin disk of stars that orbit once every few hundred million years around its central region, where hundreds of billions of stars, together with a huge mass of dark matter, provide the gravitational ‘glue’ to hold it all together.

But the pull of gravity becomes weaker far away from the Milky Way’s inner regions. In the galaxy’s far outer disk, the  making up most of the Milky Way’s gas disk are no longer confined to a thin plane, but they give the disk an S-like warped appearance.

“It is notoriously difficult to determine distances from the sun to parts of the Milky Way’s outer gas disk without having a clear idea of what that disk actually looks like,” says Dr. Chen Xiaodian, a researcher at NAOC and lead author of the article published in Nature Astronomy on Feb. 4.”

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Simulating meteorite impacts in the lab

A U.S.-German research team has simulated meteorite impacts in the lab and followed the resulting structural changes in two feldspar minerals with X-rays as they happened. The results of the experiments at DESY and at Argonne National Laboratory in the US show that structural changes can occur at very different pressures, depending on the compression rate. The findings, published in the 1 February issue of the scientific journal Earth and Planetary Science Letters (published online in advance), will aid other scientist to reconstruct the conditions leading to impact craters on Earth and other terrestrial planets.”

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Check your compass: The magnetic north pole is on the move

True north isn’t quite where it used to be.

Earth’s north magnetic pole has been drifting so fast in the last few decades that scientists that past estimates are no longer accurate enough for precise navigation. On Monday, they released an update of where true north really was, nearly a year ahead of schedule.”

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InSight’s Seismometer Now Has a Cozy Shelter on Mars

“For the past several weeks, NASA’s InSight lander has been making adjustments to the seismometer it set on the Martian surface on Dec. 19. Now it’s reached another milestone by placing a domed shield over the seismometer to help the instrument collect accurate data. The seismometer will give scientists their first look at the deep interior of the Red Planet, helping them understand how it and other rocky planets are formed.”


Much of the surface ocean will shift in color by end of 21st century: study

Climate change is causing significant changes to phytoplankton in the world’s oceans, and a new MIT study finds that over the coming decades these changes will affect the ocean’s color, intensifying its blue regions and its green ones. Satellites should detect these changes in hue, providing early warning of wide-scale changes to marine ecosystems.

Writing in Nature Communications, researchers report that they have developed a global model that simulates the growth and interaction of different species of phytoplankton, or algae, and how the mix of species in various locations will change as temperatures rise around the world. The researchers also simulated the way phytoplankton absorb and reflect light, and how the ‘s color changes as global warming affects the makeup of phytoplankton communities.”

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