Snowball Earth melting led to freshwater ocean 2 kilometres deep

A little more than 600 million years ago, you could have drunk from the ocean.

After an extreme ice age known as snowball Earth, in which glaciers extended to the tropics and ice up to a kilometre thick covered the oceans, the melt formed a thick freshwater layer that floated on the super-salty oceans. Read more in New Scientist.

Slow science

The world’s longest-running experiments remind us that science is a marathon, not a sprint.

Although science is a long-term pursuit, research is often practised over short timescales: a discrete experiment or a self-contained project constrained by the length of a funding cycle. But some investigations cannot be rushed. To study human lifespans or the roiling of Earth’s crust and the Sun’s surface, for instance, requires decades and even centuries.

Here, Nature takes a look at five of science’s longest-running projects, some of which have been amassing data continuously for centuries. Read more in Nature.

Extreme prospects

High gold prices are making it worthwhile to look for gold in some unusual places.

Demand has never been higher, but nearly all the easy gold has already been mined. So, to maintain production, mining companies are turning to more difficult sources that would have been left in the ground if gold prices had been lower. From the depths of TauTona in the South African veldt, all the way up to Pierina in the Peruvian Andes, 4,100 metres above sea level, miners are digging deeper than ever before, going to more remote locations and politically volatile regions. Read more in Nature.