20240422
An observatory at the South Pole has made the first solid detection of a type of elementary particle called the tau neutrino that came from outer space1.
Observations collected during such special requests have proven Landsat’s capabilities to capture surface details and clearly track winter ice formation and polar ocean surface temperatures even in low lighting conditions. And a new acquisition plan for the Landsat 8 and 9 satellites, dubbed Landsat Extended Acquisition of the Poles (LEAP) and first implemented in 2022, has greatly improved coverage during low- and even no-light seasons.
Instruments aboard the Landsat 8 and 9 satellites collect visual, near-infrared, and thermal infrared (heat) images. Landsat 8’s Operational Land Imager (OLI) sensor and Landsat 9’s OLI-2 sensor exhibit high sensitivity. In addition, the spatial resolution of Landsat 8’s Thermal Infrared Sensor (TIRS) and Landsat 9’s TIRS-2 is far better than the resolution of other commonly used satellite thermal sensors (100 meters for Landsat versus 375–1,000 meters for other sensors).
An analysis1 published in Nature on 27 March has predicted that melting ice caps are slowing Earth’s rotation to such an extent that the next leap second — the mechanism used since 1972 to reconcile official time from atomic clocks with that based on Earth’s unstable speed of rotation — will be delayed by three years.
Here we show that increased melting of ice in Greenland and Antarctica, measured by satellite gravity4,5, has decreased the angular velocity of Earth more rapidly than before. Removing this effect from the observed angular velocity shows that since 1972, the angular velocity of the liquid core of Earth has been decreasing at a constant rate that has steadily increased the angular velocity of the rest of the Earth. Extrapolating the trends for the core and other relevant phenomena to predict future Earth orientation shows that UTC as now defined will require a negative discontinuity by 2029.
Here we document changes in ACC strength from sediment cores in the Pacific Southern Ocean. We find no linear long-term trend in ACC flow since 5.3 million years ago (Ma), in contrast to global cooling9 and increasing global ice volume10. Instead, we observe a reversal on a million-year timescale, from increasing ACC strength during Pliocene global cooling to a subsequent decrease with further Early Pleistocene cooling. This shift in the ACC regime coincided with a Southern Ocean reconfiguration that altered the sensitivity of the ACC to atmospheric and oceanic forcings11,12,13. We find ACC strength changes to be closely linked to 400,000-year eccentricity cycles, probably originating from modulation of precessional changes in the South Pacific jet stream linked to tropical Pacific temperature variability14.
But one long gray barge docked at the port is doing its part to combat climate change. On the barge, which belongs to Captura, a Los Angeles–based startup, is a system of pipes, pumps, and containers that ingests seawater and sucks out CO2, which can be used to make plastics and fuels or buried. The decarbonated seawater is returned to the ocean, where it absorbs more CO2 from the atmosphere, in a small strike against the inexorable rise of the greenhouse gas.
Proponents say capturing CO2 from the ocean should be easier and cheaper than a seemingly more direct approach: snagging it directly from the air.