Swirling patterns in the ice of Mars’ North Pole suggest the planet is emerging out of a long ice age that began some 370,000 years ago. The findings are extremely important for climate change, improving our understanding of both Mars’ and Earth’s climate.
Isaac Smith, a planetary scientist at the Planetary Science Institute in Tucson was studying these spiral patterns carved in the ice when he noticed something unusual. What he saw were layers of ice that were seemingly deposited uniformly on the uneven terrain. To his trained eye, this looked like the mark of erosion and deposition.
Smith turned to NASA’s Mars Reconnaissance Orbiter whose Shallow Subsurface Radar can examine the various layers of terrain and material underneath the surface. The ground-penetrating radar found 87,000 cubic kilometers of ice have gathered at the poles since the last ice on Mars ended, as reported in Science. Around that time, “Mars would have actually looked more white than red,” says Smith.
“In 2003, there was an article that suggested up to a 1-meter equivalent of a global (ice) layer … and what I mean by that is if you took (ice) away from the poles and spread it over the whole planet, it would be a meter thick. That’s a lot if ice,” said Smith for R&D Mag. Since the last ice age, which ended roughly 370,000 years ago, “we found that 60 cm had moved between the poles and the mid-latitudes and that’s really good agreement with (a) one meter” global spread.
Mars is weird in this respect because ice ages on the Red Planet look a lot different than what we’re used to here on Earth. Unlike Earth’s axis, which stays tilted in a narrow range of 22 to 25 degrees, Mars’ axis wobbles greatly from 25 degrees all the way to 60 degrees. Now, going from one extreme to the other takes a lot of time, but when Mars reaches one of these extremes the equator and poles become practically reversed. Moreover, the orbit is heavily affected by a gravitational tug from Jupiter, which pulls it into an oval-shaped orbit. This way, sometimes the north pole is basking in the sun, while in other millennia it’s the south pole’s turn.
Right now, Mars is in between glacial periods. When the poles are warm, the ice migrates towards low and mid-latitude regions where it can stay stable. Based on predictive models, Mars’ next ice age will occur in about 150,000 years, Smith says.
Interestingly, the radar readings show there’s a lot of H2O and CO2 trapped in the poles. Suddenly, Elon Musk’s half-joking plan of nuking Mars’ poles to terraforming it doesn’t sound so stupid after all.