- News Home
5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
ScienceShot: What Struck Earth in 775?
3 June 2012 1:00 pm
In 775 C.E., while Charlemagne was ruling his Frankish kingdom, something mysterious struck Earth. An analysis of the rings of two Japanese cedar trees (typical tree rings shown above), reported online today in Nature, reveals that from 774 to 775 C.E., the atmospheric level of radioactive carbon-14 jumped by 1.2%. This indicates that cosmic rays—high-speed, charged particles from space—bombarded our planet and converted some atmospheric nitrogen-14 into carbon-14. Earlier work had found a rise in radioactive carbon during the same decade; the new discovery means that scientists have been able to narrow down the date of impact to within just 1 year. The scientists argue against two logical suspects: solar flares are too weak to do the job, and no supernova explosion was seen at the time, nor do any nearby supernova remnants date back to Charlemagne's time. There's also nothing unusual in the history books. So the cause remains a mystery, but whatever it was, something similar could presumably strike again.
See more ScienceShots.