Science briefs: Ask Stephen Hawking anything

Yes, you read that correctly — weeks. For those familiar with the normal AMA format, be aware that Hawking's will work slightly differently. "Due to the fact that I will be answering questions at my own pace, working with the moderators of /r/Science [Reddit's journal of science] we are opening this thread up in advance to gather your questions," Hawking wrote.

This being an AMA, redditors can, and probably will, ask Hawking about more than just the topic at hand. But Hawking has made it clear that he's participating in the popular Q and A forum as part of his recent push to introduce safety measures into the burgeoning field of AI research.

Farming may have originated 23,000 years ago, thousands of years earlier than previously thought, a study said. Researchers discovered a large number of seeds at an ancient hunter-gatherer site known as Ohalo II on the shore of the Sea of Galilee in Israel. Many of the seeds had scars, a mark that distinguishes domesticated species from wild forms.

The mix included 13 known weeds, as well as edible cereals like wild emmer, barley and oats. The mix of weeds and cereals suggests that people were experimenting with agriculture at Ohalo II, said Marcelo Sternberg, an ecologist at Tel Aviv University and an author of the study.

"These were the first cultivation trials going on," he said. "This was part of a very long learning process that our ancestors went through."

Sternberg and his colleagues, from Harvard University, Bar-Ilan University and the University of Haifa, reported their findings in the journal PLOS One.

Until now, it was believed that farming originated about 12,000 years ago in the region that now includes Iraq and parts of Turkey and Iran.

Federal and state fisheries biologists say the warm water is lethal for the cold-water species and is wiping out at least half of this year's return of 500,000 fish. "We had a really big migration of sockeye," said Ritchie Graves of the National Oceanic and Atmospheric Administration. "The thing that really hurts is we're going to lose a majority of those fish." He said up to 80 percent of the population could ultimately die.

The eggs of the spined soldier stink bug vary in color depending on how much light is reflecting from the surface onto which they are placed, according to a new study.

"The female stink bugs are using a visual assessment of the laying surface to determine the color of the egg," said Paul Abram, an entomologist at the University of Montreal. Abram and his colleagues reported their findings in Current Biology.

The species they studied, Podisus maculiventris, is the only species known to vary egg coloration based on environmental cues, Abram said. "What is actually going on inside the female stink bug at a physical level is simply unknown," Abram said. "Whatever it is, it's strange and unique."