The Tonga Volcano Eruption Caused a ‘Superbubble’ in Earth’s Ionosphere, Disrupting Satellite Navigation

GOES-18 image of Hunga Tonga Volcano. (Image: NOAA)

GOES-18 image of the Hunga Tonga volcano. (Image: via NOAA)

MICROSCOPE Mission Presents Most Precise Test of General Relativity’s Weak Equivalence Principle

The MICROSCOPE satellite.

Published in 'Physical Review Letters' and a special issue of 'Classical Quantum Gravity' on September 14, the final results from the MICROSCOPE mission measured accelerations of free-falling objects in a satellite orbiting Earth. The team found that the accelerations of pairs of objects differed by no more than about one part in 10^15, ruling out any violations of the Weak Equivalence Principle or deviations from the current understanding of general relativity at that level. (Image via ONERA)

‘Blue’ and ‘Gold’ Satellites Headed to Mars in 2024


An interplanetary mission led by the University of California, Berkeley, to put two satellites — dubbed 'Blue' and 'Gold' — into orbit around Mars has been officially authorized to prepare for launch in October 2024. (Image: AlexAntropov86 via Pixabay)

Satellites Adding to Light Pollution of Night Skies

A drawing from 2013 depicting the 17 NASA satellites that were in space at the time, shown orbiting the earth with the moon in the background.

New research has found that the light scattered off satellites and space debris orbiting Earth may be adding at least 10 percent more light to the night sky on the planet. (Image: AIRS via Flickr)

Promising Reasons Why LEO Satellites Are the Next Big Thing

NASA's Tracking and Data Relay Satellite being placed in orbit.

Low Earth Orbit (LEO) satellites range anywhere from 160 to 2,000 km above the Earth's surface. (Image: via NASA)

Does Physics Accept the Possibility of Time Travel?

A woman surrounded by many clocks.

The idea of time travel has always fascinated people. (Image: geralt via Pixabay)

Space Race: Chinese Private Company Puts Satellites in Orbit

I-Space launching a rocket.

I-Space has become the first company from China to successfully launch satellites into orbit. (Image: Screenshot via YouTube)

A Study Has Found Major Shifts in Global Freshwater

A new global, satellite-based study of Earth’s freshwater distribution found that wet areas are getting wetter and dry areas drier. The data suggest that this pattern is due to a variety of human and natural factors, including people’s use and management of water,  human-caused climate change, and natural climate cycles.

A NASA-led research team that included Hiroko Beaudoing, a faculty specialist in the University of Maryland’s Earth System Science Interdisciplinary Center (ESSIC), used 14 years of observations from the Gravity Recovery and Climate Experiment (GRACE) satellite program to track global trends in freshwater in 34 regions around the world.

The study, recently published in the journal Nature, also incorporated satellite precipitation data from the ESSIC-led Global Precipitation Climatology Project; Landsat imagery from NASA and the U.S. Geological Survey; irrigation maps; and published reports of human activities related to agriculture, mining, and reservoir operations.

Freshwater storage was higher (blue) or lower (red) than the average for the 14-year study period.
World map depicts one image in a time series of data collected by NASA’s GRACE mission from 2002 to 2016, showing where freshwater storage was higher (blue) or lower (red) than the average for the 14-year study period. (Image: via University of Maryland)

Freshwater impacted by climate change and humans

Using data taken from 2002 to 2016, the study suggests that changes in two-thirds of the 34 regions from California to China may be linked to climate change or human water use, such as large-scale pumping of groundwater for farming. Freshwater is present in lakes, rivers, soil, snow, groundwater, and glacial ice. Its loss in the ice sheets at the poles — attributed to climate change — has implications for sea level rise. On land, it is one of Earth’s most essential resources.

While some regions’ water supplies are relatively stable, others normally experience increases or decreases. But the current study revealed a new and distressing pattern. Co-author James Famiglietti of NASA’s Jet Propulsion Laboratory said in a statement:

Famiglietti noted that while water loss in some regions is clearly driven by the warming climate, such as the melting ice sheets and alpine glaciers, it will take more time before other patterns can be unequivocally attributed to climate change, saying:

The twin GRACE satellites launched in 2002 measured changes in Earth’s gravity field caused by movements of large volumes of water or other forms of mass on the planet below. Using this method, variations in terrestrial water storage were tracked until the GRACE mission ended in October 2017. However, the GRACE satellite observations alone couldn’t tell the research team what was causing the apparent trends. Hiroko Beaudoing explained:

The team found that across numerous regions, one of the big causes of groundwater depletion was agriculture, which can be complicated by natural cycles. California, which in 2017 produced more than half of the total vegetable production in the U.S., was a prime example. Decreases in freshwater caused by the state’s severe drought from 2007 to 2015 were compounded by groundwater withdrawals to support the farms in the state’s Central Valley and elsewhere.

A majority of California’s freshwater comes in the form of rainfall and snow that collects in the Sierra Nevadas, and then is managed through a series of reservoirs as it melts. When natural cycles led to dry years with diminished snowpack and surface waters, farmers and other Californians relied more heavily on groundwater.

Artist's rendering shows the twin spacecraft of the Gravity Recovery and Climate Experiement Follow-On (GRACE-FO) mission, a partnership between NASA and the German Research Centre for Geosciences GFZ. (Image credit: NASA JPL/Caltech)
Artist’s rendering shows the twin spacecraft of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, a partnership between NASA and the German Research Centre for Geosciences GFZ. (Image: via NASA JP Lvia Caltech)

Natural cycles of rainy and dry years also can cause large decreases and increases in regional amounts of freshwater. For example, in Africa, the western Zambezi basin and Okavango Delta is a vital watering hole for wildlife in northern Botswana. And during the 14-year study period, water storage in this region increased at an average rate of 29 gigatons (126 million Olympic swimming pools) per year from 2002 to 2016. This wet period during the GRACE mission followed a dry period of at least two decades.

Lead author of the paper Matt Rodell, who is chief of the Hydrological Sciences Laboratory at NASA’s Goddard Space Flight Center, said he believes this is a case of natural variability that occurs over decades in this region of Africa. He explained:

The twin GRACE satellites, launched in 2002 as a joint mission with the German Aerospace Center (DLR), precisely measured the distance between the two satellites to detect changes in Earth’s gravity field caused by movements of mass on the planet below. Using this method, GRACE tracked variations in terrestrial water storage on monthly to yearly timescales until its science mission ended in October 2017. A successor mission, called GRACE Follow-On is undergoing final preparations for launch.

Provided by: the University of Maryland [Note: Materials may be edited for content and length.]

Follow us on Twitter, Facebook, or Pinterest