June 10

Emperor Tenji of Japan commissioned the Rokoku, a clepsydra or water clock, to regulate official court ceremonies and daily life in the capital at Ōtsu. This innovative device measured time by the steady flow of water and provided precise hour indications. The introduction of the clepsydra represented the application of Chinese timekeeping technology to Japanese governance. It played a crucial role in synchronizing activities at the imperial court and improving administrative efficiency. The Rokoku symbolized the growing sophistication of scientific instruments in 7th-century Japan and laid the groundwork for future developments in horology.

On this day in 1596, the Dutch expedition led by navigator Willem Barents and captain Jacob van Heemskerk sighted the barren, wind-swept Bear Island (Bjørnøya) in the Barents Sea. The voyage aimed to discover a shorter trade route to Asia by sailing north of Norway. Despite harsh Arctic conditions, the crew charted the island’s rocky coastline and observed polar bears and seabird colonies. While they failed to find the passage, the expedition expanded European knowledge of the Arctic and paved the way for future polar exploration. Bear Island later became an important site for whaling, meteorological stations, and wildlife research.

On June 10, 1994, China carried out a nuclear detonation at Area C of the Lop Nur Test Base to validate the warhead design for its new DF-31 ICBM. This underground test was part of Beijing’s strategic modernization aimed at enhancing its second-strike nuclear capability. Information about the test later appeared in the 1999 Cox Report, raising concerns in the United States over proliferation. The DF-31 missile, equipped with multiple independently targetable reentry vehicles (MIRVs), represented a significant advancement in China’s nuclear arsenal. The test underscored growing global tensions over arms development and the challenges of nuclear non-proliferation.

Professor Kevin Warwick and his wife connected bioelectronic implants in their nervous systems to send signals between each other. Using electrodes interfaced with the median nerve of one participant, electrical pulses were transmitted to the other’s sensory cortex. This experiment marked a groundbreaking step toward human–machine integration and neural interface technology. It demonstrated the potential for restoring movement in paralyzed patients and advancing prosthetic control. Warwick’s work opened new research avenues in neuroprosthetics, brain–computer interfaces, and cybernetics.

On June 10, 2003, NASA’s Mars Exploration Rover ‘Spirit’ lifted off aboard a Delta II rocket from Cape Canaveral. Its goal was to search for evidence of past water activity on the Martian surface using onboard instruments. Spirit landed successfully in Gusev Crater on January 4, 2004, exceeding its planned 90-day mission by years. The rover discovered signs of ancient volcanic activity and silica-rich soil, pointing to past hydrothermal systems. Spirit’s achievements provided crucial insights into Mars’s geological history and paved the way for future missions.

On June 10, 2018, NASA's Mars rover Opportunity sent its final communication to mission control on Earth. Originally landing on the Martian surface in January 2004, Opportunity vastly exceeded its planned 90-day mission. Over nearly 15 years, the rover discovered evidence of ancient water flows and collected thousands of high-resolution images. In June 2018, a massive dust storm enveloped Mars, cutting off the rover's solar power and ending its communications. After months of recovery attempts, NASA officially declared the mission over on February 13, 2019. Opportunity holds the record for the longest-operating rover on Mars, significantly advancing our understanding of the Red Planet.