(left to right): LIGHTFIELD STUDIOS/SUTTERSTOCK.COM; RUALDO MENEGAT; WARREN CORNWALL

Top stories: Emotional colors, a Machu Picchu mystery, and the battle to save Alaska’s salmon

Researchers can guess where you’re from by how colors make you feel

Whether you see red, feel blue, or go green with envy may depend on what country you call home, a new study suggests. And when given data on how a person associated colors with emotions, researchers could correctly predict where they were from 80% of the time.

Machu Picchu was built over major fault zones. Now, researchers think they know why

Archaeologists and architects alike have long wondered why 15th century Incans built the grand citadel of Machu Picchu where they did, high in the remote Andes atop a narrow ridge in what is now Peru. One simple answer, researchers now suggest, is that that’s where building materials for the site—large amounts of already fractured rock—were readily available.

How a salmon scientist got hooked into a battle over the world’s largest gold mine

A massive gold mine proposed for the sockeye salmon spawning grounds of southwestern Alaska could bring in hundreds of billions of dollars and employ more than 1000 people—but opponents argue the mine poses long-term risks to the area’s salmon runs, including toxic runoff and habitat destruction. Daniel Schindler, an aquatic ecologist and a second-generation environmental activist, is on the front lines of the fight.

Can you spot the duplicates? Critics say these photos of lionfish point to fraud

Oona Lönnstedt, a marine biologist formerly at Uppsala University in Sweden, was fired for making up data in a 2016 Science paper on microplastics and fish larvae. Now, photographs she and colleagues have posted to the Biology Letters website raise fresh questions about whether the group committed an earlier fraud.

Quantum computer bests all conventional computers in first claim of ‘supremacy’

The age of quantum computing may have begun not with a flashy press conference, but with an internet leak. According to a paper posted briefly—and presumably mistakenly—to a lab site, physicists at Google have used a quantum computer to perform a calculation that would overwhelm the world’s best conventional supercomputer. Although the specific computation has no known use, the result means scientists have passed a milestone known as “quantum supremacy.”