What happened
Donald Trump has suffered another legal defeat over postal voting after the US Supreme Court declined to let his administration introduce tighter requirements for mail-in ballots ahead of November’s midterm elections. The justices left in place a lower court order preventing the US Postal Service from implementing the measures, which included checking voters against citizenship lists. Twenty-three states and Washington DC had challenged the changes, arguing that election administration is a state responsibility.

Who said what
Conservative justice Brett Kavanaugh backed the immediate decision, but suggested that the administration could ultimately prevail. He said applying the proposed rules this year would be “arbitrary and capricious”, while justices Samuel Alito and Clarence Thomas dissented. They described the legal challenge as a “Hail Mary pass”. Trump has argued that tighter postal controls are needed to prevent electoral fraud despite having previously voted by mail himself.

This is “not the first setback on postal ballots for Trump before the Supreme Court”, said Lisa Lambert on the BBC. In June the justices ruled that states could count ballots postmarked by election day, rejecting an effort by the Trump administration to exclude them.

What next?
The latest ruling is unlikely to settle the dispute, with the underlying legal battle continuing. Some states have already begun sending out ballots for November’s elections, which will determine control of Congress and Senate.

What happened
Three African wild dogs in Zambia have completed an unprecedented 2,485-mile (4000km) journey across the continent, marking what researchers believe is the longest recorded movement by an African mammal.

Scientists say the mammoth trek, tracked by GPS collars, offers hope that wildlife can still travel across vast distances despite growing human pressures.

Who said what
The research, published in the journal Ecology, “adds weight to calls to create strips of natural land outside protected areas that connect separate wildlife areas broken apart by roads, towns, or farms”, said the BBC.

Bruce Ellender, one of the paper’s co-authors, told the broadcaster that species that roam over large areas, such as wild dogs and elephants, needed connected landscapes if they were to survive into the future. “We can’t see these protected areas as islands and expect them to be functional in the long term; we need to think much broader than that.”

What next?
African wild dogs are among the continent’s rarest predators, with only about 6,000 remaining. Researchers said the movement also demonstrated that wild dog populations across parts of southern and eastern Africa might be even more connected than previously thought.

While fog can create an eerie, lonely atmosphere, it’s actually teeming with life. Scientists have found vibrant microbial communities in low-hanging clouds, including bacteria that can detoxify air pollution. And these microbes could play a larger role in our air quality than previously thought.

Fog water can have “bacterial concentrations similar to those in continental or marine bodies of water” and “contain microbiomes well-differentiated in composition from those in the dry aerosol microbiomes”, said a study published in the journal mBio. While scientists had been aware that bacteria and other microbes existed in the air, not much was known about “whether those airborne microbes are doing much”, be it “growing, feeding, dividing and changing the air around them” or “simply waiting to land somewhere better”, said ZME Science.

While “fewer than 1% of fog droplets contain bacteria”, when “averaged together they represent an astounding amount of life”, said a release from Arizona State University (ASU). “When you take all of the droplets together, the concentration of bacteria is the same as in the ocean,” said study co-author Professor Ferran Garcia-Pichel, the director of ASU’s Biodesign Center for Fundamental and Applied Microbiomics.

And the potential for “harvesting fog for drinking water has also been up for discussion”, said The Weather Channel. “Now we need to consider and further study if these air-cleaning benefits are too good to pass up.”

People “think of fog as just water droplets”, said study co-author Derek Straub, an associate professor at Susquehanna University. But there’s a “tremendous amount happening inside those droplets that we are only beginning to understand”.