A 2013 photograph captured in the dense jungle vegetation deep within the Monteverde Tropical Rainforest Preserve in Costa Rica.
1973: Preserving the Biodiversity of Tropical Rainforests and Cloud Forests

Tropical rainforests and cloud forests are crucial for biodiversity, facing threats from human exploitation. Reserves like Costa Rica’s Monteverde are key to their conservation

World maps depicting the ages of seafloor crust. Red indicates the youngest regions, including the currently forming crust, while blue represents the oldest oceanic crust still in existence, formed approximately 150 to 180 million years ago.
1973: Seafloor Spreading – Tanya Atwater’s Contributions to Plate Tectonics

Tanya Atwater’s groundbreaking research in the 1970s provided key insights into seafloor spreading, contributing significantly to the understanding of plate tectonics and the geological history of Earth

The first scientist on the Moon, geologist Jack Schmitt, examining and collecting soil and rock samples during the Apollo 17 mission in December 1972. Photographed by the mission commander, Gene Cernan.
1972: Lunar Geology – Insights from Apollo Astronaut Harrison Schmitt

The Apollo Moon missions, particularly with geologist-astronaut Harrison Schmitt, showed that Earth's geological principles apply to lunar exploration, contributing significantly to our understanding of the Moon and planetary geology

A false-color composite image captured by the Landsat-1 satellite on July 25, 1972, showcasing the Dallas/Fort Worth metropolitan area in Texas. The varying colors represent different levels of vegetation cover (in shades of red) and the health of plant life.
1972: The Evolution and Impact of Earth Science Satellites

Earth science satellites, evolving since the 1960s, have transformed our understanding of the Earth, enabling detailed environmental and climate observations and fostering global collaboration in Earth observation

A bustling crowd in New York City gathered for the inaugural Earth Day celebration on April 22, 1970.
1970: Celebrating Earth Day – A Global Movement for Environmental Awareness

Earth Day, celebrated on April 22, emerged from the environmental activism of the 1960s, highlighted by Rachel Carson's work, fostering global awareness and action for environmental stewardship and sustainability

This X-ray image reveals the presence of magnesium (red), calcium (green), and aluminum (blue) within the Murchison meteorite, an exceedingly ancient carbonaceous chondrite that dates back more than 4.55 billion years. This meteorite contains primitive minerals that condensed from the solar nebula, as well as water and intricate organic molecules. Among its remarkable contents are over 70 types of amino acids.
1970: The Cosmic Search for Life – Insights from Meteorites

The discovery of amino acids in the Murchison meteorite supports the notion that life's essential molecules are prevalent throughout the universe, underscoring the potential for extraterrestrial life

This computer-generated model showcases the Apollo 8 Command Module, which achieved the historic feat of becoming the first crewed spacecraft to escape Earth's gravitational pull and orbit the Moon in December 1968. The scene illustrates the approximate positioning of the spacecraft, Earth, and Moon when the crew captured the iconic color photograph known as the "Earthrise."
1968: The Historic Journey of Apollo 8 – Escaping Earth’s Grasp

Apollo 8's historic mission marked humanity's first escape from Earth's gravity, paving the way for future space exploration beyond low Earth orbit

Morning Glory Pool, located in Yellowstone National Park, Wyoming, is a hot spring with vibrant colors along its outer edges. These colors result from a diverse community of hyperthermophilic bacteria that can thrive in the extreme high-temperature conditions of the spring, which can exceed 176°F (80°C).
1967: Exploring Extremophiles – Unveiling Life in Earth’s Extreme Environments

Thomas Brock's discovery of extremophiles revolutionized our understanding of life's potential in extreme environments, influencing the search for extraterrestrial life

The inaugural "selfie" of Earth from deep space, captured by the Lunar Orbiter I spacecraft on August 23, 1966, and digitally enhanced in 2008.
1966: Capturing the Blue Marble – The Evolution of Earth Selfies in Space

Earth selfies, starting with the V-2 rockets and culminating in the Lunar Orbiter I's iconic 1966 image, have revolutionized our perspective of Earth, inspiring environmental awareness and a sense of global unity

Evolutionary biologist Lynn Margulis, a key figure in the development of the cellular endosymbiosis theory.
1966: The Evolutionary Theory of Endosymbiosis – Tracing the Origins of Cellular Complexity

Endosymbiosis, first proposed by Konstantin Mereschkowski and later advanced by Lynn Margulis, is a fundamental evolutionary theory explaining the origin of complex eukaryotic cells from symbiotic relationships with prokaryotic organisms