In 1929, Edwin Hubble discovered that the universe is expanding. This discovery led to the development of the Big Bang theory, which is the prevailing model for the origin and evolution of the universe.
In 1930, Clyde Tombaugh discovered Pluto, the ninth planet in our solar system. Pluto was later reclassified as a dwarf planet, but it remains an important object of study for space scientists.
In 1969, Neil Armstrong and Buzz Aldrin became the first humans to walk on the Moon. This historic event marked the beginning of the Space Age, and it inspired a generation of scientists and engineers.
In 1995, the Hubble Space Telescope discovered that the universe is much older than previously thought. This discovery led to a reassessment of our understanding of the universe's history.
In 2004, the Spirit and Opportunity rovers landed on Mars.