Blog – Page 95

Using the James Webb Space Telescope (JWST), astronomers have conducted spectroscopic observations of a high-redshift galaxy known as XMM-VID1-2075. Results of the observational campaign, presented August 14 on the pre-print server arXiv, suggest that XMM-VID1-2075 is a massive and evolved slow-rotator.

The so-called “slow-rotators” represent a small fraction of the most massive galaxies, which stopped forming stars and are dispersion-supported systems. Such galaxies are highly evolved and often exist in dense cluster environments.

To date, no slow-rotators have been confirmed from stellar kinematics beyond the redshift of 2.0. It is generally assumed that at high redshifts, these slow-rotating systems are predicted to be rarely found.

A new study has uncovered a surprising and concerning paradox: although Earth’s vegetation cover has expanded dramatically over the past four decades, this widespread “greening” trend is often associated with a decline in soil moisture, particularly in water-scarce regions. The study is published in Communications Earth & Environment.

Led by Prof. Chen Yaning from the Xinjiang Institute of Ecology and Geography of the Chinese Academy of Sciences, the researchers employed a multifaceted approach, integrating multi-source satellite observations, reanalysis datasets, and outputs from 12 Earth system models. This comprehensive analysis, spanning the years from 1982 to 2100, enabled researchers to quantitatively assess the causal relationship between vegetation dynamics and soil moisture.

Their findings reveal that while an impressive 65.82% of the global vegetated areas have experienced greening, nearly half of these areas simultaneously witnessed significant soil drying—a “greening-drying” pattern. This detrimental trend is most pronounced in vulnerable regions like Central Africa, Central Asia, eastern Australia, and mid-to-high latitude Europe.