The spinning orbs may help to explain the origin of such heavy elements in space

Gold may be a glittery leftover from a newborn black hole’s messy first meal.

Gold is a heavy element. So is platinum. And uranium. These and many other heavy elements might form when rapidly spinning, massive stars collapse into newly formed black holes. Known as collapsars, these stars get their name from that collapse. And as this last dying stage of their lives take place, layers of gas around them explode. That collapse and explosion leave a disk of material swirling around each new black hole. When that black hole devours the surrounding material, the conditions become just right for gold, platinum and other heavy elements to form, scientists now report. Read more.

Here’s how scientists have organized time throughout Earth’s 4.6-billion-year history

Imagine the nearly unimaginable: 4.6 billion years. That’s how old the Earth is — a mind-boggling length of time. And to measure it, scientists use special terms, most of which focus on the planet’s changing geology. That’s why, in fact, it’s known as geologic time.

To grasp just how old Earth is, imagine fitting its entire history into one calendar year. If Earth formed on January 1, the earliest primitive life (think algae) wouldn’t appear until March. Fish first swam onto the scene in late November. Dinosaurs stomped around from December 16 until December 26. The first modern humans — Homo sapiens — were real late-comers. They didn’t show up until just 12 minutes before midnight on New Year’s Eve. Read more.

There have been long periods of cooling in Earth’s history. Temperatures had already fallen for more than 10 million years before the last ice age began about 2.5 million years ago. At that time, the northern hemisphere was covered with massive ice masses and glaciers. A geoscientific paradigm, widespread for over 20 years, explains this cooling with the formation of the large mountain ranges such as the Andes, the Himalayas and the Alps. As a result, more rock weathering has taken place, the paradigm suggests. This in turn removed more carbon dioxide (CO₂) from the atmosphere, so that the greenhouse effect decreased and the atmosphere cooled. This and other processes eventually led to the ice Age. Read more.

We are the only primates walking exclusively on two legs. Doing so leaves our hands free to make and use tools.

This, the experts claim, was a crucial development in the evolution of early humans. But there is little consensus as to how the radical change from walking on all fours to standing upright came about. In a paper recently published, Kansas-based physicists Adrian Melot and Brian Thomas put forward a novel theory. Supernovae, they claim, forced our ancestors to become bipeds. Read more.