Taxonomy term

april 2017

And then there was one: Ceres' disappearing ice volcanoes

Earth has numerous volcanoes, both active and extinct — some of which continue to tower over landscapes long after they finished erupting. On the chilly dwarf planet Ceres, however, scientists have identified just a single volcano — an ice-erupting cryovolcano — raising questions about whether others ever existed there and, if so, what happened to them. In a new study, researchers suggest that Ceres has likely had other volcanoes, but that, over time, their icy slopes have been flattened beyond recognition.

28 Apr 2017

Grapes reveal impacts of sulfur-rich Samalas eruption on 13th-century climate

The A.D. 1257 eruption of the Indonesian volcano Samalas sent an ash plume an estimated 43 kilometers into the sky in one of the most sulfur-rich eruptions of the last 7,000 years. A new study using tree rings, ice cores and historical records investigates how this colossal eruption impacted climate across the Northern Hemisphere, finding that the eruption triggered severe cold in some regions, while other areas were less affected. The pattern could be explained by the behavior of sulfate particles in the atmosphere, researchers suggest.

28 Apr 2017

Geologic Column: My China syndrome

The rapid pace of change in China over the last decade — witnessed by the author on a half dozen visits to his son who lives there — has been staggering.
28 Apr 2017

Down to Earth With: Paleontologist Gerta Keller

The mass extinction that did in the dinosaurs is one of the best-known events in geology. It’s also one of the most contentious.

27 Apr 2017

Mastodon bones point to significantly earlier human presence in North America

In 1992, paleontologists from the San Diego Natural History Museum discovered a set of fossil bones, tusks and teeth from a single mastodon next to state highway 54 south of San Diego. Archaeologists were soon called to investigate the site, which also featured several large cobblestones — unique in the otherwise sandy matrix surrounding the bones — that seemed to have been used to break open the mastodon’s long bones, hinting at human activity soon after the animal’s death. A reliable age for the intriguing find has eluded scientists for more than two decades, but in a study released today in Nature, researchers who successfully dated the bones have come to a sensational conclusion: The site appears to date back roughly 130,000 years, more than 100,000 years before humans are thought to have lived in North America.

26 Apr 2017

Venezuela, Central Africa are Earth's lightning hot spots

People who live around Venezuela’s Lake Maracaibo call it a “lighthouse.” The lake’s “never-ending storm” has been written about for centuries, and the incessant lightning there has even helped guide Caribbean sailors. Data from NASA’s Tropical Rainfall Measuring Mission (TRMM) has now confirmed that Lake Maracaibo is Earth’s top lightning hot spot.

24 Apr 2017

Tallying temperature drops inside tornadoes

The inside of a strong tornado is an intense place, with wind speeds of more than 450 kilometers per hour and dramatic drops in air pressure and temperature. But due to the dangerous unpredictability of such storms, few real-time measurements have been taken inside actual twisters. In a new study, researchers took a mathematical approach to circumvent the danger and calculate temperature changes inside tornadoes, offering a glimpse into how these violent storms operate.

24 Apr 2017

Benchmarks: April 24, 1990: The Hubble Space Telescope is launched

Five hundred and eighty kilometers above Earth, orbiting at more than 27,000 kilometers per hour, is a 12-ton, bus-sized eye on the universe: the Hubble Space Telescope. When Hubble launched aboard the space shuttle Discovery on April 24, 1990, scientists hoped it would provide answers to many of the great unknown questions of the day. How old is the universe? How fast is it expanding? What lies between galaxies?

24 Apr 2017

Tropical rainfall shifts resulted in greener Sahara

Six thousand years ago, the Sahara — today the world’s largest nonpolar desert, stretching over an area larger than the contiguous United States — was dotted with lakes and vegetation. Rock paintings from that time depict a much wetter landscape, and show elephants, hippos, antelope and many other animals living in the region.

21 Apr 2017

Massive dust storm caused by climate, not conflict

In August and September 2015, a massive dust storm swept across the Middle East, engulfing seven nations in sand thick enough to ground flights, trigger respiratory distress for many, and obscure the region from satellites. At the time, the unprecedented size of the storm was blamed on the ongoing conflict in Syria, with unusual amounts of dust being raised from abandoned agricultural lands and increased military traffic. But a new study cites a combination of climatic factors and weather as the more likely culprits.

20 Apr 2017

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