First, there was a violent shock. Then, there was the roar of a 30-foot-high wave of water, throwing fish onto a sandbar in what is now North Dakota. Then there was a hail of molten rock, pelting dying fish and soon-to-be-dying land creatures. Then the fires began.
Tiny bubbles that were trapped inside 2.7 billion-year-old rocks have led scientists to conclude that Earth’s atmosphere was less than half as dense as it is today – which runs counter to conventional wisdom.
Scientists had assumed that our planet’s atmosphere was thicker billions of years ago, in order to retain heat and keep the planet warm enough for life during an era when the sun shone less brightly than it does today.
“Our result is the opposite of what we were expecting,” Sanjoy Som, an astrobiologist at NASA’s Ames Research Center in California, said in a news releasefrom the University of Washington.
Som is the principal author of a study reporting the findings, published today by Nature Geoscience. He conducted the research during his doctoral studies at the UW, and retains a Seattle connection as the CEO of a nonprofit space science outreach group called Blue Marble Space.
Millions of years from now, could alien geologists pinpoint a distinct time when humans changed the world? An international team of scientists says they could, by looking at the crushed-up remains of concrete, aluminum and plastics.
Further evidence would come in the form of dramatic spikes in radioactive fallout and fossil-fuel particulates, the researchers report in this week’s issue of the journal Science. And if environmental trends proceed the way most scientists think, the aliens also could document the signs of sea level rise and mass extinctions –perhaps including our own.
“All of this shows that there is an underlying reality to the Anthropocene concept,” the University of Leicester’s Jan Zalasiewicz, a co-author of the study, said in a news release.
Many scientists have said our current era should be called the Anthropocene Epoch rather than the Holocene Epoch, thanks to the ways in which human activity is drastically altering global ecosystems. The latest study lays out detailed evidence arguing that the Anthropocene Epoch is already geologically distinct, with its start dated to around 1950.
A newly published analysis of the geological record for the area around the site of 2014’s Oso landslide shows that the slopes have been collapsing every 140 years or so on average. That’s significantly more frequent than previously estimated.
Based on laser elevation measurements and radiocarbon dating of woody debris around the North Fork of the Stillaguamish River, researchers from the University of Washington found that a collapse five times as big as the Oso event, known as the Rowan landslide, took place sometime between 300 and 694 years ago.
The researchers’ study, published online by the journal Geology on Tuesday, came up with an average collapse rate of once per 500 years for the area around Oso, Wash., over the course of thousands of years. Over the past 2,000 years, the average rate has been about 140 years, the scientists said.
The omnibus spending bill that was approved by Congress today includes another $8.2 million for a quake-monitoring system that could provide early warning if we’re hit by “the Really Big One” that everyone’s been freaked out about.
Sen. Patty Murray and Rep. Derek Kilmer, both D-Wash., had pushed for the additional support and issued a statement applauding the legislative follow-through.
“An updated and operational Earthquake Early Warning System is essential to serve as eyes and ears for folks on the West Coast,” Kilmer said. “A few crucial seconds can make all the difference to help Washingtonians get out of harm’s way if a large quake strikes.”
The omnibus bill was signed into law by President Barack Obama.
Researchers have long been concerned about the potential for the Cascadia Subduction Zone to unleash a magnitude-9.0 quake off the coast of Washington and Oregon. The concern was heightened in July by a scary report in The New Yorker, headlined “The Really Big One.”