Introduction:
In August, India celebrated a historic milestone with the successful landing of Chandrayaan – 3 on the moon surface. Prime Minister Narendra Modi lauded the achievement, asserting that India had reached the uncharted territory of the moon’s south pole. However, a leading figure in China’s lunar exploration program, Ouyang Ziyuan, challenged this claim, sparking a debate over the precise landing site and its proximity to the lunar south pole.
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The Indian Lunar Landing:
On August 23, 2023, Chandrayaan-3 made a historic landing on the moon, marking India’s success as the fourth country to achieve this feat. Prime Minister Modi applauded the scientists for their hard work and dedication, asserting that the spacecraft had landed near the moon’s south pole.
Chinese Cosmochemist’s Dispute:
Ouyang Ziyuan, a prominent figure in China’s lunar exploration program, disputed India’s claim regarding the landing site. He contended that Chandrayaan-3 did not land near the lunar south pole, citing specific latitude coordinates. According to Ouyang, the lunar rover landed at a latitude of around 69 degrees south, falling within the southern hemisphere but outside what he defined as the polar region.
Understanding the Latitude Debate:
The discrepancy in interpretations arises from differing definitions of the moon’s polar region. The Earth’s rotational axis tilt influences the delineation of polar regions. While the European Space Agency defines the south pole as 90 to 80 degrees south, NASA’s definition extends to 90 to 66.5 degrees south.
Definition of South pole
The rover touched down at approximately 69 degrees south latitude, according to Ouyang. He clarified that while it was within the moon’s southern hemisphere, it didn’t fall within what he defined as the polar region, a zone he identified as between the latitudes of 88.5 and 90 degrees.
Given Earth’s tilt at about 23.5 degrees concerning the sun, the southern pole is delineated between 66.5 and 90 degrees south. Ouyang argued that due to the moon’s slight tilt of only 1.5 degrees, the polar region on the moon was comparatively smaller.
Image Credits: Nasa, Ouyang Ziyuan
The European Space Agency acknowledged that strictly speaking, the Chandrayaan-3 landing site wasn’t the south pole, attributing the challenge to the location near the rim of the Shackleton crater.
In the United States, NASA defined the “entire” polar region as ranging from 80 to 90 degrees south. By this definition, Chandrayaan-3 landed outside the polar region but achieved a higher latitude than prior moon missions.
NASA’s chief, Bill Nelson, conveyed congratulations to the Indian Space Research Organisation for their successful “lunar south pole landing” on August 23 via a message shared on X, formerly known as Twitter.
Expert Opinions and Academic Research:
Several experts weighed in on the controversy, with some aligning with Ouyang’s view and others acknowledging India’s achievement.
Richard de Grijs, a professor at Macquarie University, emphasized that while Chandrayaan-3 did not land within the Antarctic Circle, it reached a high-latitude region on the moon, a significant achievement in itself.
“While the probe’s landing site is frequently referred to as the ‘polar region’ in news media and other publications, the location of Chandrayaan-3 is not within the lunar Antarctic Circle, defined as the lunar geographic region further south than 80 degrees south,”
Richard de Grijs, a professor at Macquarie University’s School of Mathematical and Physical Sciences in Sydney
De Grijs referred to a scholarly article authored by researchers from the Physical Research Laboratory, a division of the Indian government’s space department. Published in the peer-reviewed journal Monthly Notices of the Royal Astronomical Society in early August, the paper outlined the team’s efforts in selecting a landing site, characterizing it as a “high-latitude location on the moon.”
The Essence of the Debate:
The debate, while touching on technicalities and semantics, underscores the incredible achievement of Chandrayaan-3. Landing near the lunar south pole or in its vicinity represents a significant leap in lunar exploration, providing opportunities for further scientific research and potential resource utilization.
Planetary dynamicist Lee Man-hoi, associated with the University of Hong Kong, highlighted that Chandrayaan-3 had reached the most extreme southern latitude ever achieved by a lunar lander. He further emphasized the Indian team’s characterization of the landing site as a “high-latitude location.”
Astrophysicist Quentin Parker, leading the Laboratory for Space Research at HKU, emphasized that the dispute was becoming overly focused on technical definitions.
“The moment you land a rover close to the south pole and certainly within what’s defined as the south pole region is already a major achievement,” he said. “I think that nothing should be taken away from India because of that.”
~Quentin Parker, HKU Lead
Conclusion:
While the precise definition of the lunar south pole’s location remains a point of contention, Chandrayaan-3 undeniably stands as a monumental achievement for India’s space program. The discourse around the landing site highlights the enthusiasm and competition among nations in the realm of space exploration, ultimately advancing human knowledge and pushing the boundaries of what is possible beyond our planet.
Reference: South China Morning Post.
