Mars may have underground volcanoes that could be responsible for the liquid water believed to flow underneath the polar ice cap, according to a new study.

Last year, researchers suggested in a study published in the journal Science that there is liquid water under Mars' south polar ice cap. Now, new research has offered a possible explanation for how liquid water could exist beneath the ice cap: volcanoes.

Finding liquid water underneath thick ice sheets is common on Earth as the planet's heat causes ice to melt where it touches the crust. The study published last year claimed that a similar phenomenon is happening on Mars, but it did not explain how liquid water could exist at the base of Mars' ice cap.

Published in the AGU journal Geophysical Research Letters, the new study does not take sides as to whether there is actually liquid water in Mars' south pole. Instead, researchers theorized that there must have been recent magmatic activity under the surface of the Red Planet for there to be enough heat to produce liquid water underneath the ice cap that is about a kilometer and a half thick. The study's authors suggested that the formation of a magma chamber within the past few hundred thousand years could be the cause.

However, the scientists also said that if there was no recent magmatic activity underneath Mars' surface, then it is unlikely that there is actually liquid water beneath the planet's ice cap.

"Different people may go different ways with this, and we're really interested to see how the community reacts to it," Michael Sori, co-author of the study and an associate staff scientist in the Lunar and Planetary Laboratory at the University of Arizona, said in a press release.

While it does not prove the existence of liquid water on Mars, the new study is intended to further the debate about it. The presence of liquid water on Mars could be a big flag for possible life outside Earth. It could also serve as a resource for future human exploration of the Red Planet.

Ali Bramson, co-lead author of the new paper and postdoctoral research associate at the Lunar and Planetary Laboratory at the University of Arizona, said that any life on Mars could be found in the subsurface of the planet to avoid radiation.

"If there are still magmatic processes active today, maybe they were more common in the recent past, and could supply more widespread basal melting," Bramson continued. "This could provide a more favorable environment for liquid water and thus, perhaps, life."

According to the study, magma from Mar's interior rose toward its surface about 300,000 years ago. But it didn't breach the surface and only pooled in a magma chamber in the subsurface. The magma chamber released heat that melted the ice at the bottom of the ice cap. Scientists believe that this may still be happening to this day.

Mars may have underground volcanoes heating up the base of its south polar ice cap like Earth. Pictured: An aerial view taken on July 13, 2018, shows steam and lava at the Piton de la Fournaise on the Indian Ocean island of Reunion, which erupted overnight according to the Piton de la Fournaise volcano observatory (OVPF). Getty Images/Richard Bouhet