On Earth, the examine of ice core samples is certainly one of many strategies scientists use to reconstruct the historical past of our previous local weather change. The identical is true of Mars’ northern polar ice cap, which is made up of many layers of frozen water which have collected over eons. The examine of those layers may present scientists with a greater understanding of how the Martian local weather modified over time.
This stays a problem because the solely method we’re in a position to examine the Martian polar ice caps proper now’s from orbit. Fortunately, a staff of researchers from UC Boulder was ready to make use of knowledge obtained by the High-Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter (MRO) to chart how the northern polar ice caps’ developed over the previous few million years.
The analysis was performed by Andrew Wilcoski and Paul Hayne, a Ph.D. scholar and assistant professor from the Laboratory for Atmospheric and House Physics (LASP) on the College of Colorado Boulder. The examine that describes their findings just lately appeared within the Journal for Geological Research (JGR), a publication maintained by the American Geophysical Union (AGU).
For the sake of their examine, Wilcosky and Hayne sought to find out the present state of the Martian North Polar Residual Cap (NPRC), which is important to understanding the North Polar Layered Deposits (NPLD). Utilizing the high-resolution pictures gathered by the HiRISE instrument, Wilcosky and Hayne examined the tough options of the NPRC – which incorporates ripples and ridges of various measurement and form.
They then modeled the expansion and recession of NPRC over time primarily based on its interplay with photo voltaic radiation and the way the speed of development and loss is affected by the quantity of atmospheric water vapor. What they discovered was that along with inflicting the formation of tough terrain (ripples and ridges) in an ice sheet, publicity to photo voltaic radiation may even trigger ice to sublimate inconsistently.
Mainly, Mars’ axial tilt, which is chargeable for it experiencing seasonal modifications just like Earth, additionally causes one aspect of those options to sublimate (the Solar-facing aspect) whereas the opposite doesn’t. This has the impact of exaggerating these options, resulting in pronounced ridges and valleys that turn out to be extra pronounced as time goes on.
Total, the mannequin employed by Wilcoski and Hayne decided that the tough options noticed by the MRO ought to measure 10 m (33 ft) in diameter and 1 m (3.Three ft) deep. Moreover, their outcomes demonstrated that because the options age, the spatial wavelength (the gap) between every ripple will increase – from 10 to 50 m (164 ft). As they state of their examine:
“Our outcomes present that the scale of mounds and depressions on the ice cap floor counsel that it took 1–10 thousand years to type these roughness options. Our outcomes additionally counsel that the formation of options on the floor might depend upon when water vapor is current within the environment over the course of a 12 months (e.g., summer time or winter).”
These outcomes are according to the pictures taken by the HiRISE instrument of the Martian North Polar Residual Cap (NPRC). What they indicated is that the tough options noticed round Mars’ northern polar ice shaped throughout the final 1000 to 10,000 years, which offers scientists with a place to begin for reconstructing the local weather historical past of Mars.
Such is the character of the Purple Planet. Right this moment, scientists have a reasonably good understanding of the character of the Martian panorama and the way it modifications all year long. Additionally they have an thought of what it used to appear like billions of years in the past, because of impeccably-preserved floor options that point out the previous presence of flowing and standing water (rivers, streams, and lakes).
However the intervening interval, the place the local weather transitioned from one to the opposite, that’s the place a lot stays to be realized. Within the coming years, robotic missions could possibly be despatched to Mars for the sake of finding out the ice sheets immediately and perhaps even return samples to Earth. Within the subsequent decade, as astronauts start to set foot on Mars, the chance to discover the ice caps is also attainable.