Mostly, these genetic fragments are generally nothing more than molecular fossils. Over thousands of generations, they have mutated so much that they cannot replicate in our cells. And our cells keep the viral DNA muzzled to minimize the harm it might cause.
But scientists are finding that some endogenous retroviruses do wake up, and at the strangest time. (...)
The Moon was created 4.47 billion years ago, according to a new study of meteorites containing ancient fragments from the giant collision that formed the Earth and its lunar companion.
The findings reported in the journal Science, also provide astronomers with a new tool for determining the age of major events in the early history of the solar system.
The giant impact hypothesis or 'Big Splash' implies that the Moon coalesced from debris flung into orbit after a Mars-sized planet called Theia collided with the early proto-Earth.
While the big splash hypothesis is now widely accepted among scientists, the precise timeline of this event is still disputed.
"We now have found not only the age of the Moon, but also what is the starting point for our Earth, the time when our world began to become the world that we know today," says the study's lead author Dr William Bottke of the Southwest Research Institute in Boulder, Colorado.
"The impact that made our Moon was probably one of the biggest events to occur in the inner solar system."
Bottke and colleagues also believe it was the last collision of this magnitude to occur, but putting an exact date on the event has been difficult. (...)
Stanford University scientists have invented the first high-performance aluminum battery that's fast-charging, long-lasting and inexpensive. Researchers say the new technology offers a safe alternative to many commercial batteries in wide use today.
"We have developed a rechargeable aluminum battery that may replace existing storage devices, such as alkaline batteries, which are bad for the environment, and lithium-ion batteries, which occasionally burst into flames," said Hongjie Dai, a professor of chemistry at Stanford. "Our new battery won't catch fire, even if you drill through it."
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The battery bounce test, popularized in online videos, has led to the common conclusion that a high bounce means a dead battery. But researchers at Princeton University have found that bouncing is not actually an effective way to check a battery's charge.