Accurate, real-time monitoring of ionospheric dynamics is essential for understanding space weather and protecting satellite-based navigation and communication systems. 

When two black holes merge or two neutron stars collide, gravitational waves can be generated. They spread at the speed of light and cause tiny distortions in space-time. Albert Einstein predicted their existence, and the first direct experimental observation dates from 2015. Now, Prof. Ralf Schützhold, theoretical physicist at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), is going one step further. He has conceived an experiment through which gravitational waves can not only be observed but even manipulated. Published in the journal Physical Review Letters (DOI: 10.1103/xd97-c6d7), the idea could also deliver new insights into the hitherto only conjectured quantum nature of gravity.

Acute sepsis alters how intravenous fluids and vasoactive drugs function in the body. Using a sheep model, researchers examined how sepsis affects the distribution of crystalloid fluids and the effectiveness of vasoactive drugs. Results showed that sepsis reduced urine output, weakened drug responses, and caused fluid to accumulate in the interstitial “third fluid space.” These findings highlight how sepsis disrupts normal fluid regulation, complicating effective fluid and drug management during treatment.

The National Institute of Information and Communications Technology (NICT) has successfully demonstrated 2 Tbit/s Free-Space Optical (FSO) communication using small optical communication terminals that can be mounted on satellites and HAPS, marking a world first for this technology.

This experiment involved horizontal free-space optical communication between two types of small portable optical terminals developed by NICT: a high-performance FX (Full Transceiver) installed at NICT Headquarters (Koganei, Tokyo) and a simplified ST (Simple Transponder) installed at an experimental site 7.4 km away (Chofu, Tokyo). Despite the difficult conditions of an urban environment with atmospheric turbulence that disrupts laser beams, the system maintained a stable total communication speed of 2 Tbit/s via Wavelength Division Multiplexing (WDM) transmission of 5 channels (400 Gbit/s each). This is the first time in the world that terabit-class communication has been realized using terminals miniaturized enough to be mounted on satellites or HAPS.

Moving forward, NICT plans to further miniaturize the terminals for implementation onboard a 6U CubeSat. NICT aims to conduct free-space optical communication demonstrations at speeds of up to 10 Gbit/s between a Low Earth Orbit (LEO) satellite (altitude approx. 600 km) and the ground in 2026, and between a satellite and HAPS in 2027. Through these experiments, NICT will demonstrate compact, ultra-high-speed data communication capabilities and pave the way for the realization of Beyond 5G/6G Non-Terrestrial Networks (NTN).

To address the global environmental and climate crisis and advance the UN SDGs, it is essential to fully leverage Earth observations (EO) through the integration of atmospheric, hydrological, cryospheric, lithospheric, ecological, and socio-economic data. Based on discussions from the 2023 “Towards Global Earth Observatory” workshop, this paper highlights the fragmented nature of current EO and data repositories and emphasizes the need for a more coordinated global Ground-Based Earth Observatory (GGBEO). We summarize the status of key in-situ and ground-based remote sensing systems and outline the actions required to build an integrated GGBEO with interoperable data repositories, unified observation networks, and sustainable long-term support.

The first exoplanet ever discovered in 1995 was what we now call a “hot Jupiter”, a planet as massive as Jupiter with an orbital period of just a few days. Today, hot Jupiters are thought to have formed far from their stars—similar to Jupiter in our Solar System—and later migrated inward. Two main mechanisms have been proposed for this migration: (1) high-eccentricity migration, in which a planet’s orbit is disturbed by the gravity of other celestial bodies and subsequently circularized by tidal forces near the star; and (2) disk migration, in which the planet moves gradually inward within the protoplanetary disk.

However, it is not straightforward to distinguish the mechanism a particular hot Jupiter experienced from observations alone. In the case of high-eccentricity migration, the gravitational perturbations can tilt the planet’s orbital axis relative to the star’s rotational axis, resulting in a measurable misalignment. However, tidal forces can realign these axes over time, meaning that an aligned orbit does not necessarily imply disk migration. As a result, there has long been no reliable observational method to identify planets that formed through disk migration.

To address this challenge, a research group led by PhD student Yugo Kawai and Assistant Professor Akihiko Fukui at the Graduate School of Arts and Sciences, the University of Tokyo, proposed a new observational method that takes advantage of the timescale of high-eccentricity migration itself.

Fluorine is critical for biomedicine. This element can help drug compounds be more potent and last longer in the body, and its radioactive isotope, fluorine-18, powers medical imaging techniques such as positron emission tomography (PET). But scientists have long struggled with adding fluorine to the most common chemical bonds—carbon–hydrogen (C–H) bonds—in a way that’s precise, efficient and compatible with the molecules used to create many modern medicines. There’s been particular interest in constructing carbon–fluorine bonds stereoselectively—that is, attaching fluorine from a specific direction in space to create the needed fluorinated stereoisomer (“mirror image” form) of the target molecule. Stereoselective C–H fluorination has remained one of the most challenging synthetic transformations, and the limited approaches developed to date have relied on expensive specialty chemicals or complicated, multi-step procedures. Now, chemists at Scripps Research have developed a long-sought method to stereoselectively attach fluorine atoms to complex, drug-like molecules in a single step using cheap, readily available fluoride salts. 

Neutron stars are compact objects with strong gravity and extreme magnetic fields. A research team investigated long-term X-ray variability in the neutron star NGC 7793 P13. This object is thought to be driven by supercritical accretion, where an extraordinary amount of gas falls onto the object and emits intense X-rays. The team found a mysterious relation between the X-ray luminosity and the rotation velocity. This result could provide clues to reveal the supercritical accretion mechanism.