The lack of clues left behind by ancient Americans has made it difficult for researchers to pinpoint precisely when humans first arrived on the continent. However, it has always been believed to be about 13,000 years ago, just as the world was thawing from the last ice age. Now, evidence from the Chiquihuite Cave in Zacatecas, Central Mexico, seems to suggest that prehistoric humans may have been living in North America as early as 30,000 years ago.
Male birds typically sing the same tunes as the rest of their species because an unrecognizable song defeats the two primary reasons for their crooning — to establish and defend their territory and to attract mates. While the songs, which are passed down from generation to generation, may vary slightly by region, any new compositions are typically limited to the local environment. However, for reasons unknown to scientists, white-throated sparrows across Canada are abandoning their classic song for a catchy new tune "written" by their peers in British Columbia.
Scattered across the ocean bed, and often hidden from the human eye, are hundreds, or perhaps even thousands, of "blue holes." The massive underwater sinkholes, which host a diverse biological community — ranging from coral to sponges to sharks to sea turtles — were formed thousands of years ago when groundwater dissolved karst, a type of porous limestone rock found on ocean floors.
American civil rights leader and U.S. Representative John Lewis (D-GA) passed away on July 17, 2020, following a seven-month battle with pancreatic cancer. The 80-year-old dedicated his life to building what he called "The Beloved Community" in America — first as a civil rights leader and then as a lawmaker advocating, for reforms on issues from gun control to health care.
Over the years, there have been numerous attempts to create "glow-in-the-dark" plants. However, none of the approaches — which included infusing plants with nanoparticles of the luciferins and enzymes needed for the phenomenon to occur, or incorporating them with bacterial bioluminescence genes – proved feasible.
On July 18, 2020, about 150 Paris residents settled inside 38 electric boats floating on the Seine river to enjoy a free screening of Le Grand Bain — a 2018 comedy about a group of middle-aged men forming a synchronized swim team. The city's first "Cinema sur L'Eau," or "Cinema on Water," was organized by MK2 Cinemas to celebrate the June 22 reopening of the country's movie theaters, which had been shuttered since mid-March to stem the rapid spread of the novel coronavirus.
Even those not normally interested in astronomy will find it hard to resist NEOWISE, the brightest comet to grace our skies since the 1997 appearance of Comet Hale-Bopp. The spectacular cosmic snowball of frozen gas, rock, and dust has been visible to those willing to wake up before dawn since early July. However, it has now risen high in the evening skies and can be viewed with the unaided eye by even the most casual stargazer.
The solar system is about to get busy! In the next few weeks, a slew of spacecraft will embark on a one-way journey to Mars, to seek evidence of past life and to further investigate its unusual atmosphere. The back-to-back missions are timed to take advantage of the short window of opportunity — caused by celestial mechanics — that will allow them to reach the Red Planet in the most efficient and cost-effective manner.
