Mars is covered with gravitational scars – some of the most prominent are the craters. Another particularly unusual example is often shown in this new image from ESA’s Mars Express: an ancient trio that does not consist of one but three overlapping craters.
The trio of craters located in a particularly old part of Mars’ southern hemisphere is called Noachis Terra. The area was devastated during the Noachian era, an ancient period about 4 billion years ago in the history of Mars in which a large number of asteroids and comets flew inward to crash into the area. planet surface. Some of the features created by these collisions are still intact on Mars today, and when they formed in the early days of the Solar System, are of particular interest to scientists who are seeking to know more about our neighboring planet and its past.
Signs of Noachian’s turbulent processes and events are seen especially clearly in the southern highlands of Mars, home to many old craters, which wear down over time. ESA’s Mars Express has photographed many of the craters in the area, from severely eroded Greeley crater, named after American geologist Ronald Greeley, to patterned Neukum crater, located after the name of one of the founders of the Mars Express mission (and the spacecraft’s former Principal Investigator of High-Resolution Stereo Camera (HRSC), the camera was responsible for this new image).
This image shows a triple crater found just east of a more famous feature called Le Verrier Crater, which stretches for nearly 140 kilometers. In contrast, the three concave points seen here are somewhat smaller; the largest is 45 km across and the smallest 28 km.
How would such a triple crater form? One possible explanation – and that arguably most likely – is that the collider broke into three before it hit the ground, forming a trio of craters on impact. Not all “multi-impact actions” leave such neat and distinct features, instead many agents show elongated grooves, non-circular voids lying next to each other, or only a portion of the catchment overlaps. Another possible explanation is coincidence: at different times, three separate colliding agents could have hit the Martian surface in this position, creating a neat superposition. of the craters completely by accident.
Interestingly, if the impact was indeed fragmented and broken, this could imply that Noachian Mars’ atmosphere is much denser – and harder to penetrate – than it is now. This points towards an early Mars that was much warmer and wetter than the arid, cold world we see today. Observations from multiple missions support this view and return evidence that water once passed through the Red Planet in large numbers, revealing features such as old river valley networks and large lake basins. is believed to have formed during the Noachian period.
Like many ancient and eroded craters in the southern highlands of Mars, these three have a flat rim, shallow layer and have been filled with sediments four billion years after their formation. . There is also evidence of ice here – the smallest crater with traces often created as ice and debris creep across the surface, similar to how mixed glaciers and ice or glaciers cover full of moving debris in the high mountains of the Earth.
This frame may have previously contained other craters, as indicated by circular arrays of depressed surfaces in the upper right and lower left. In fact, despite the obnoxious nature of Noachis Terra, the surroundings of this trinity are very peaceful for such ancient terrain. Only a handful of small surrounding craters have well-defined, clearly defined rims and bowls, indicating that they are relatively young and have not yet begun to suffer severe erosion. Overall, it appears that older craters in this area have ‘melted’ to the surface – a phenomenon due to ice again.
As the ice just below the Martian surface melts and melts for many million years, the soil becomes softer. This soft, ice-rich soil will settle more quickly and fill the dents and dents more easily, contributing to the smooth look of this part of Noachis Terra. This certainly suggests that there was a large amount of water present on Mars, at least during the Noachian period, capable of producing an abundant glacial flow like glaciers.
Understanding the history of Mars and detailed mapping the planet’s surface cover features is the main goal of the Mars Express. The spacecraft has been exploring the Red Planet since its launch in 2003 and is preparing to cooperate with some of the new missions that have already joined – or will soon join – the spacecraft at Mars. The ESA-Roscosmos ExoMars Trace Gas Orbiter (TGO) orbiter arrives in 2016 and the ExoMars Rosalind Franklin explorer and accompanying surface science platform are scheduled to launch in September 2022.
Together with the Mars Express, these missions will work to fully characterize our neighbor, to help us not only understand more about Mars, but also be able to make a further comparison of history and version. the substance of our home in the Universe.
Neukum Crater is named after the founder of Mars Express
Provided by the European Space Agency
Quote: The ancient trio of craters on Mars (2020, October 30) retrieved October 31, 2020 from https://phys.org/news/2020-10-ancient-crater-triplet-mars .html
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