An asteroid impact was likely not responsible for the extinction of the North American megafauna – such as mammoths, saber tooth cats, giant ground sloths and Dire wolves – along with the Clovis hunter-gatherer culture some 13,000 years ago, suggests a new study in PNAS.
When the last ice age came to an end approximately 13,000 years ago and the glaciers covering a large portion of the North American continent began melting and retreating toward the north, a sudden cooling period known as the Younger Dryas reversed the warming process and caused glaciers to expand again. Even though this cooling period lasted only for 1,300 years, a blink of an eye in geologic timeframes, it witnessed the disappearance of an entire fauna of large mammals.
New images from the ESA's Herschel space observatory reveal the formation of previously unseen large stars that reside in the Rosette Nebula, each one up to ten times the mass of our Sun.
Astronomers say it is important to understand the formation of high-mass stars in our Galaxy because they feed so much light and other forms of energy into their parent cloud they can often trigger the formation of the next generation of stars.
About a dozen teens with social-communication disorders sit in a tight circle, cradled in couches and chairs in a conference room at the UC Davis M.I.N.D. Institute. They listen intently as Marjorie Solomon, the leader of the Institute’s social skills training program, guides them in a discussion of what it means to have and be a friend.
“What makes you trust another person?” Solomon asks. “Do you make friends easily? Do you pick friends who are similar to you?” she asks.
The answers spill out, sometimes freely, sometimes with more coaxing. “I trust other people when I know they can keep a secret,” one participant volunteers. “Someone who will help me out in a jam,” another says. “Someone who will stick by me over time,” offers another.
