Red dot sights have proliferated into every corner of the firearms world in recent years and, today, they are better than ever. These non-magnified optics, which use a battery to project a luminous ...

Vehicles and buildings designed to enable survival in extreme environments, such as spacecraft, submarines and sealed shelters, heavily rely on systems for the management of carbon dioxide (CO 2).

For decades, scientists have been baffled by two enormous, enigmatic structures buried deep inside Earth with features so vast and unusual that they defy conventional models of planetary evolution.