The colors of rubies and emeralds are so striking that they define shades of red and green—ruby red and emerald green. But ...

When the Sun is near the horizon, its light passes through a lot more of the atmosphere to reach the Earth's surface than ...

Pulse Oximeters May Misread Oxygen Levels in People of Color. the FDA Wants to Change That WASHINGTON (AP) — Makers of medical devices that quickly measure oxygen levels in the blood would have ...