Science
Science News from the Associated Press
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Glacial Remnants in New York
NEW YORK (AP) — Crews excavating the World Trade Center site this summer for the foundations of a new skyscraper have uncovered features carved into the bedrock by glaciers about 20,000 years ago, including a 40-foot-deep pothole.
Exposing the solid rock beneath at the ground zero site in lower Manhattan is critical for supporting what will be Tower 4 of the new World Trade Center, being built by Silverstein Properties.
“You want to make sure you’re not perching something on a ledge,” said Anthony Pontecorvo, a supervising structural engineer at Mueser Rutledge Consulting Engineers, which is working on the project.
While removing the overlying soil is an engineering necessity, the digging has given scientists a rare window into the deep past and formations like the huge pothole.
“There are areas in local parks that have small vertical potholes exposed,” Cheryl J. Moss, the senior geologist at Mueser Rutledge, told The New York Times. “But I’m not aware of anything in the city with a whole, self-contained depression on this scale.”
Solar Minimum Prolonged
WASHINGTON (AP) — The sun has dialed back its furnace to the lowest levels seen in the space age, new measurements from a space probe show.
But don’t worry — it’s too small a difference to change life on Earth, scientists said Yesterday. In fact, it means satellites can stay in orbit a little longer.
The solar wind — a stream of charged particles ejected from the sun’s upper atmosphere at 1 million miles per hour — is significantly weaker, cooler and less dense than it has been in 50 years, according to new data from the NASA-European solar probe Ulysses.
And for the first time in about a century, the sun went for two months this summer without sunspots, said NASA solar physicist David Hathaway. That record was broken Monday when a cluster of eight sunspots surfaced. Sunspots are temporary regions of high magnetic activity that from Earth appear to be black splotches.
The cause for the sun's slight weakening seems to be a change in its magnetic flux, said Dave McComas of the Southwest Research Institute. Why it's happening is a mystery, but it has fluctuated like this in the past.