All Stories by Sid Perkins
- Earth
Outside-In: Clearing up how cloud droplets freeze
A fresh look at old experimental data suggests that water droplets in clouds freeze from the outside inward rather than from their core outward.
- Earth
Bursting in Air: Satellites tally small asteroid hits
On average, a small asteroid slams into Earth's atmosphere and explodes with the energy of 1,000 Hiroshima-size blasts once every thousand years or so, a rate that is less than one-third as high as scientists previously supposed.
- Earth
Once Upon a Lake
As Earth warmed at the end of the last ice age, the immense volumes of fresh water that occasionally and catastrophically spilled from Lake Agassiz—the long-defunct lake that formed as the ice sheet smothering Canada melted—may have caused global climate change and sudden rises in sea level.
- Planetary Science
Echoes of Icequakes: Simple probe could measure Europa’s ocean and icy shell
A football-size space probe could provide a low-cost way to determine whether there's a liquid ocean on the Jovian moon Europa.
- Paleontology
Trackway site shows dinosaur on the go
Scientists say that a sediment-filled, bathtub-shape depression found at one of North America's most significant dinosaur trackway sites is the first recognized evidence of urination in dinosaurs.
- Paleontology
Curved claws hint at pterosaur habits
A study of the claws of flying reptiles known as pterosaurs suggests that some of the creatures may have walked like present-day herons and used their wing fingers to hold prey.
- Paleontology
Mosasaurs were born at sea, not in safe harbors
Newly discovered fossils of prehistoric aquatic reptiles known as mosasaurs suggest that the creatures gave birth in midocean rather than in near-shore sanctuaries as previously suspected.
- Paleontology
Stegosaur tails packed a punch
A mathematical analysis of a fossil stegosaur's bones leaves little doubt that the creature's spike-studded tail was an effective defense against predators.
- Paleontology
Dear Mummy: Rare fossil reveals common dinosaur’s soft tissue
A mummified dinosaur unearthed in Montana a year ago is giving scientists a rare peek at what the creature's muscles and other soft tissues may have looked like.
- Earth
Shifting Sands
Sand dunes can provide scientists with clues about ancient patterns of wind and precipitation.
- Earth
Moderate flows help carve rivers
Measurements of erosion in a rocky river channel in Taiwan suggest that the day-to-day flow of water accounts for more rock wear there than occasional catastrophic floods do.
- Earth
Much that glitters is really old
New isotopic analyses of rock samples from one of the world's richest gold-mining regions suggest that the flecks of gold in those ores are more than 3 billion years old.
