Top stories: Volcanic sunsets, a world without oil, and how our hearts evolved for endurance

This sulfur-spewing Russian volcano is turning sunsets purple

Sunrise and sunset chasers discovered something odd this summer: In rural Colorado and the rest of the Northern Hemisphere, Earth’s daily light shows were turning purple. Now, weather balloons probing the stratosphere have traced the mysterious purple light to a volcanic eruption in Russia.

Can the world make the chemicals it needs without oil?

Many of the world’s coveted chemicals—those that make up paint, plastics, pesticides, and more—are made from black, gooey oil in reactions powered by fossil fuels. But with climate concerns on the rise, chemists are searching for more sustainable ways to create the materials that make up the modern world.

Running—or sitting—can change the shape of your heart

Scientists have long known that humans are built for endurance, with our shock-absorbing joints and springy tendons. Now, a new study shows people’s hearts are also optimized for stamina—though how much depends on whether we run, farm, or stay put on the couch.

What kind of researcher did sex offender Jeffrey Epstein like to fund? He told Science before he died

In September of 2017, just over 2 years before disgraced financier Jeffrey Epstein took his own life, he talked to Science about how he decided which scientists were worthy of his money. Epstein’s comments—some boastful, others tone-deaf or downright offensive—reveal a nuanced picture of the motivations and biases behind the millionaire’s shadowy contributions to science.

Study on DNA spread by genetically modified mosquitoes prompts backlash

For the past decade, researchers have been testing ways to control disease-carrying mosquito populations by releasing genetically modified (GM) males into the wild, where they mate with females and produce sickly or sterile offspring. A new study suggests one such trial, run by the company Oxitec, produced offspring that survived— and carried the genetically modified DNA. That genetic material could cause the entire mosquito population to become fitter, the authors argue, a statement that has triggered anti-GM news reports, a backlash from some scientists, and strong pushback from Oxitec.