A Breakthrough from Ahmedabad
A team of planetary scientists from the Physical Research Laboratory (PRL) in Ahmedabad has offered new insights into the dramatic climate of Mars. Their research, published in the journal Current Science, explains how two key factors—the planet’s lopsided
orbit and its colossal landforms—interact to produce extreme temperature swings and powerful atmospheric waves. While India’s famed Mars Orbiter Mission (Mangalyaan) concluded its service after years of successful data collection, this new study shows how Indian scientists continue to play a leading role in planetary exploration by leveraging international data, in this case from the Emirates Mars Mission's Hope spacecraft.
The Red Planet's Wobbling Journey
Part of the climate puzzle lies in Mars's journey around the Sun. Unlike Earth’s nearly circular path, Mars follows a highly elliptical orbit. This means its distance from the Sun changes significantly throughout its year. Critically, Mars is closest to the Sun during the southern hemisphere's summer, making that season far more intense than summer in the north. The PRL scientists noted that this orbital quirk leads to temperatures in some southern regions being roughly 25 Kelvin higher than in corresponding northern seasons. This solar imbalance is a primary driver of the planet-wide temperature fluctuations, which can range from a relatively mild 27 degrees Celsius in summer to a frigid minus 113 degrees Celsius in winter.
How Giant Craters Shape the Weather
The planet’s orbit is only half the story. The other crucial element is its dramatic topography. The Indian researchers focused on two massive impact basins: Hellas Planitia, the largest preserved impact crater on Mars, and the Argyre basin. These are not just craters; they are continent-sized depressions with immense depth. Hellas Planitia, for instance, contains the lowest elevations on the entire planet. The study reveals that these massive features physically disrupt the flow of Mars's thin atmosphere. As air moves across these basins, it is forced to compress and expand, creating large-scale atmospheric patterns known as zonal waves. These waves are like ripples in a pond, giving scientists an indirect way to track how air circulates across the globe.
The Grand Climate Combination
The key finding from the PRL team is how these two factors—orbit and terrain—combine. The researchers observed different wave patterns in the two basins. Argyre was dominated by a simpler pattern, while Hellas showed more complex wave structures that changed with the seasons. This shows that the intense solar energy received during Mars's close approach to the Sun doesn't just warm the planet evenly; its effect is shaped and channelled by the massive geological features on the ground. The deep basins act like giant mixing bowls for the atmosphere, taking the energy from the lopsided orbit and turning it into complex weather systems. The team's analysis provides a more detailed picture of this thermal behaviour than was previously available, even noting that existing climate models were often about 10 Kelvin cooler than what their real-world observations showed.
Why This Discovery Matters
Understanding Mars's climate is not just an academic exercise. For future robotic and, eventually, human missions to the Red Planet, knowing the weather is critical for survival. This research provides a much-needed update to our climate models, helping to predict dust storms, temperature drops, and atmospheric pressure changes with greater accuracy. For India, this study reinforces its position as a major contributor to space science. Building on the legacy of Mangalyaan, which significantly advanced our understanding of the Martian exosphere, Indian scientists continue to unlock the secrets of other worlds. This work showcases a collaborative and data-driven approach to science that keeps India at the forefront of planetary exploration.
