Jupiter, the fifth planet from the Sun, is the largest in our solar system, with a mass exceeding twice that of all other planets combined. This gas giant, though massive, is a thousand times lighter than the Sun. Positioned at 5.20 AU from the Sun, Jupiter completes an orbit every 11.86 years. Known since ancient times, it stands out as the third brightest object in our night sky, surpassed only by the Moon and Venus. The planet inherits its name from Roman mythology, honoring Jupiter, the king of gods.
1906: Discovery of 588 Achilles
Max Wolf discovered the first Trojan asteroid, 588 Achilles, in 1906. These asteroids are trapped in Jupiter's gravitational field at Lagrangian points.
1932: Discovery of Ammonia and Methane in Jupiter's Atmosphere
In 1932, Rupert Wildt made a significant discovery by identifying absorption bands of ammonia and methane in the spectra of Jupiter, providing crucial insights into the composition of the gas giant's atmosphere.
1938: Observation of Three White Ovals on Jupiter
Three long-lived anticyclonic features known as "white ovals" were observed in Jupiter's atmosphere in 1938. These features maintained their distinct identities for several decades, occasionally approaching each other but never merging until 1998.
1939: Three White Oval Storms Observed on Jupiter
Between 1939 and 1940, three smaller white oval-shaped storms were observed on Jupiter, which would eventually merge to form Oval BA.
1940: Three White Oval Storms Observed on Jupiter
Between 1939 and 1940, three smaller white oval-shaped storms were observed on Jupiter, which would eventually merge to form Oval BA.
1955: Discovery of Jupiter's Radio Emissions
Bernard Burke and Kenneth Franklin made a groundbreaking discovery in 1955 when they observed that Jupiter emits bursts of radio waves at a frequency of 22.2 MHz. This finding provided valuable insights into the planet's magnetic field and radiation belts.
1973: Pioneer 10's Flyby of Jupiter
In 1973, the Pioneer 10 spacecraft conducted a flyby of Jupiter, marking a significant milestone in space exploration. This mission provided valuable data and images of the gas giant, revealing important details about its atmosphere and phenomena.
1973: Pioneer Missions Capture First Close-Up Images of Jupiter
In 1973, the Pioneer missions marked a pivotal moment in space exploration by capturing the first close-up images of Jupiter's atmosphere and several of its moons. These images provided unprecedented views of the gas giant and its surroundings.
1973: First Robotic Probe Exploration of Jupiter
The exploration of Jupiter using robotic probes began in 1973, marking the start of a series of missions to study the gas giant.
1976: Formal Naming of Jupiter and its Satellites
In 1976, the International Astronomical Union officially adopted the name "Jupiter" for the planet, aligning with its Roman nomenclature. They also established a convention of naming Jupiter's newly discovered moons after the lovers, favorites, and descendants of the Roman god Jupiter.
1979: Voyager Measures Great Red Spot
In 1979, the Voyager missions observed that the Great Red Spot on Jupiter had shrunk to a length of 23,300 kilometers and a width of approximately 13,000 kilometers.
1979: Voyager 1 Discovers New Jovian Moons
Before the Voyager 1 probe's flyby in 1979, a total of eight additional moons orbiting Jupiter were discovered.
February 1992: Ulysses Studies Jupiter's Magnetosphere
In February 1992, the Ulysses solar probe conducted a flyby of Jupiter, utilizing the planet's gravity to adjust its trajectory into a polar orbit around the Sun. During this maneuver, Ulysses studied Jupiter's magnetosphere, gathering data on its magnetic field and charged particles.
July 1994: Comet Shoemaker–Levy 9 Impact
Comet Shoemaker–Levy 9 collided with Jupiter in July 1994, offering a unique opportunity for astronomers worldwide to observe the impacts' effects on Jupiter's atmosphere.
1994: Galileo Witnesses Comet Shoemaker–Levy 9 Impact
In 1994, the Galileo spacecraft, while en route to Jupiter, witnessed the impact of Comet Shoemaker–Levy 9 with the gas giant. This event provided a unique opportunity to observe the effects of a cometary impact on a planetary atmosphere.
July 1995: Galileo Probe Enters Jupiter's Atmosphere
In July 1995, the Galileo spacecraft released a 340-kilogram titanium atmospheric probe that entered Jupiter's atmosphere on December 7. The probe collected data on the planet's atmosphere during its descent.
December 7, 1995: Galileo Enters Orbit Around Jupiter
On December 7, 1995, the Galileo spacecraft made history by becoming the first spacecraft to enter orbit around Jupiter. This mission revolutionized our understanding of the gas giant and its moons, providing unprecedented observations and data.
1995: Hubble Observes Great Red Spot Shrinkage
Hubble Telescope observations in 1995 showed a reduction in the size of Jupiter's Great Red Spot to 20,950 kilometers.
1997: Potential Impact Scar Discovery
In 1997, while investigating possible impact observations, scientists found that a dark feature on Jupiter's surface, discovered by Giovanni Cassini in 1690, might be an impact scar.
1998: Merger of Two White Ovals on Jupiter
In 1998, two of the three long-lived white ovals observed in Jupiter's atmosphere in 1938 merged, signifying a change in the planet's atmospheric dynamics.
1999: Discovery of New Jovian Moons
Since 1999, the discovery of many small outer moons challenged the traditional classification of Jupiter's moons, leading to a more complex understanding of the system.
2000: Cassini's Flyby of Jupiter
In 2000, the Cassini probe, en route to Saturn, performed a flyby of Jupiter, capturing higher-resolution images of the gas giant and its features. This flyby provided valuable data and insights into Jupiter's atmospheric dynamics and moon system.
2000: Formation of Oval BA from Merging White Ovals
Following the merger of two white ovals on Jupiter in 1998, the remaining oval merged with the combined feature in 2000, resulting in the formation of Oval BA.
2000: Formation of Oval BA
In 2000, a new atmospheric feature resembling a smaller version of the Great Red Spot emerged in Jupiter's southern hemisphere. This feature, named Oval BA, formed from the merging of three smaller white oval-shaped storms that had been present since 1939-1940.
September 21, 2003: Galileo Orbiter's Intentional Crash into Jupiter
On September 21, 2003, the Galileo orbiter was intentionally steered into Jupiter's atmosphere, where it burned up. This decision was made to prevent any possibility of the spacecraft colliding with and potentially contaminating Jupiter's moon Europa, which scientists believe might harbor life.
2005: JIMO Cancellation
NASA's ambitious Jupiter Icy Moons Orbiter (JIMO) mission was canceled in 2005 due to funding challenges.
2007: New Horizons Observes Jupiter's Volcanic Activity
During its 2007 flyby of Jupiter, the New Horizons probe captured data on the plasma output from volcanoes on Jupiter's moon Io, providing valuable insights into the moon's volcanic activity.
2008: Jupiter's Impact Shield Debate
In 2008, computer simulations suggested Jupiter may not be protecting the inner solar system from comets. The simulations indicated that Jupiter's gravity might redirect comets inward, sparking controversy among scientists about its true effect on cometary orbits.
2009: Great Red Spot Size Decreases to 17,910 km
In 2009, observations revealed that the Great Red Spot on Jupiter had decreased in size to 17,910 kilometers.
April 2011: EJSM/Laplace Partnership Ends
In April 2011, the ESA formally ended its partnership with NASA on the EJSM/Laplace mission, citing budgetary concerns and scheduling conflicts.
2015: Great Red Spot Shrinking at 930 km per Year
As of 2015, the Great Red Spot on Jupiter was measured at approximately 16,500 by 10,940 kilometers, with its length decreasing at a rate of about 930 kilometers per year.
July 4, 2016: Juno Mission Arrival
On July 4, 2016, NASA's Juno mission arrived at Jupiter to study the planet from a polar orbit.
August 27, 2016: First Juno Flyby
Juno completed its first flyby of Jupiter on August 27, 2016, capturing and sending back unprecedented images of Jupiter's north pole.
2016: Discovery of Babylonians' Use of Trapezoidal Rule
A 2016 research paper revealed that Babylonians utilized the trapezoidal rule before 50 BC to calculate the integral of Jupiter's velocity along the ecliptic.
April 2017: Discovery of the "Great Cold Spot" on Jupiter
In April 2017, scientists discovered a "Great Cold Spot" in Jupiter's thermosphere at its north pole. This feature, spanning 24,000 kilometers across and 12,000 kilometers wide, is about 200 degrees Celsius cooler than the surrounding atmospheric material.
July 2018: Juno Mission Extension
Originally planned for a 20-month mission, Juno completed 12 orbits by July 2018. NASA extended the mission, allowing for continued observation and study of Jupiter.
2020: Proposed Launch of EJSM/Laplace
The EJSM/Laplace mission, a joint effort by NASA and ESA, was initially planned for launch around 2020 but was later canceled.
July 2021: Second Juno Mission Extension
Juno's mission was further extended to July 2021, allowing for even more detailed study of Jupiter and its atmosphere.
October 2021: Juno Measures Great Red Spot Depth
In October 2021, the Juno spacecraft conducted measurements revealing that the depth of the Great Red Spot on Jupiter ranges from 300 to 500 kilometers.
April 14, 2023: JUICE Launch
The European Space Agency launched its Jupiter Icy Moon Explorer (JUICE) on April 14, 2023, marking a significant step in the exploration of Jupiter's icy moons.
2024: Europa Clipper Launch
NASA's Europa Clipper mission, set to launch in 2024, aims to explore Jupiter's moon Europa and its potential for harboring life.
September 2025: Juno Mission Conclusion
The Juno mission is slated to conclude in September 2025. To avoid potential collisions with Jupiter's moons, the spacecraft will perform a controlled deorbit and disintegrate in Jupiter's atmosphere.
2035: Proposed Tianwen-4 Launch
The Chinese National Space Administration aims to launch its Tianwen-4 mission around 2035, targeting Jupiter's system, specifically Callisto, with an orbiter.