Scientists were only able to estimate what the planet's internal structure might be before InSight arrived. Their main clues were its size, mass, and moment of inertia. Other clues were provided by meteorites, orbiters, and in-situ sampling by rovers.
When InSight arrived on Mars in November of last year, better data started streaming in.
One of the most compelling questions about Mars is what happened to its magnetosphere, which keeps our planet warm and dry for billions of years. The magnetosphere is created by the outer core of our planet. Evidence shows that Mars had a magnetosphere and a liquid rotating core. Magnetization in Martian rocks tells us something. What happened to it?
We need better data on the interior of Mars to answer that. The three primary instruments are SEIS, HP3 and RISE. HP3 needed to burrow into the ground to gather its data. The other instruments are still working despite HP3 failing.
A new study examines marsquakes. The seismometer measures marsquakes, meteorite impacts, and other internal activity by monitoring seismic waves.
The lead author of the study is from the Institute of Geology and Geophysics at the Chinese Academy of Sciences. The co-author is a professor at the ANU Research School of Earth Sciences. The journal Nature Communications has a study in it.
Most of what we know about Mars is provided by physical parameters. The seismometers carried by NASA's Viking Landers were largely useless. They were not deployed directly on the ground. The data was degraded by the wind on the lander decks. The seismometer of Viking 1 failed, but Viking 2 was able to detect a marsquake, which was much lower than the Earth's.
The SEIS instrument is a huge improvement over the Viking seismometers, but it has some limitations. Earthquakes have larger waves than Marsquakes, so they can be scattered or lost in the noise. When it comes to their exact locations, this leads to uncertainties. It's difficult to pin down the physical cause of earthquakes since the SEIS instrument is the only recording station. It is difficult to come to any conclusions about the activity in the Mars mantle because it is hard to determine the nature of the deep interior.
The researchers wanted to know more about the SEIS data. They thought there could be more marsquakes hidden in the data, which both automated and manual searches missed.
Mars is the focus of interest in marsquakes. There are two faults on Mars over 1,000 km long. They are geologically young and formed several million years ago. Four strong, clear earthquakes have been detected in the region. The authors of the study used their characteristics to find more earthquakes.
A scientist hadn't identified 47 more marsquakes before, but the researchers found them. There were earthquakes under the region.
The majority of the new marsquakes are associated with two previous ones. These two earthquakes are important in Martian seismic studies because they are high-quality detections. They are the strongest and clearest marsquakes yet detected, and two of them, called S0173a and S0235b, were especially valuable detections.
There were 47 marsquakes in the area. The professor says that the quakes suggest that Mars is more active than thought. They are hidden in ambient noise.
marsquakes that occur at all times of the day can have other causes, and as far as Tkalcic and Sun are concerned, the reason must be the molten material in the upper mantle. The core and the material are sandwiched between each other. Previous studies have shown that the marsquakes are caused by tectonic activity.
The movement of molten rock in the Martian mantle is believed to be the cause of the 47 new marsquakes.
The earthquakes are enough for Tkalcic to conclude that the Martian mantle is mobile and that it is a highly seismically active region. Our understanding of Mars depends on that conclusion.
The number of marsquakes recorded during the day and night after the InSight landing suggests that the interior of Mars is in motion, according to the authors.
The researchers acknowledge that their conclusion isn't rock-solid. The conclusion almost reaches itself when they compare the activity on Mars with the activity on Earth.
It all came down to the heat. The molten iron in Earth's outer core helps create the planet's magnetosphere. The molten iron is generated by the electrical currents created by the convection. Scientists wondered if the interior of Mars had cooled and prevented electrical currents. This may have happened billions of years ago, ending the period of habitability.
If the mantle is still active, that complicates the picture.
It can help us answer fundamental questions about the solar system if we know that the Martian mantle is still active.
The marsquakes help us understand if the convection is occurring inside the planet, and if it is based on our findings, there must be another mechanism at play that is preventing it.
There are other indications that Mars still has some mantle mobility and a liquid core. The details are not clear. We don't know how thick that liquid part of its core is. If the liquid layer is too thin, it won't be able to sustain a large force.
That is the case on Mars, where what is left of the liquid core can cause a magnetic field. Remnant crustal magnetism is the majority of Mar. What happened to the core? All indications are that Mars had a larger liquid core in the past, and that it generated a magnetosphere that protected the planet for a long period of time. It might be long enough for simple life to flourish.
The makeup of the core and the influence of light elements could be the answer.
There is an alternative explanation, which is a hypothesis that needs to be examined.
In a planet's core, Immiscible solutions tend to separate and some of the material becomes stratified. It's bad for convection.
The liquid would preferentially separate to the Fe-H and Fe-S volumes, and this would have had catastrophic consequences for Mars, its atmosphere and potential life on its surface.
The same thing did not happen on Earth. But why? Earth's core is taking longer to cool due to its size, but luckily it didn't happen on Earth.
Was Earth lucky? No two planetary histories follow the same path.
The titanic collision early in Earth's history may have played a role.
If a large body like Theia collides with the Earth to give birth to the Moon, the internal structure of the Earth could be changed.
Mars may have suffered a giant impact that affected its core, which is complicating the whole picture. There is some evidence that may have happened. Mars is scarred by at least five giant impacts. The largest basin is the Borealis basin. It is almost 10,000 km wide and covers most of the northern hemisphere. Could that have affected the liquid core of Mars?
It could have, according to some research. A giant impact occurring within the first 500 Myr of martian history may have an influence on the initiation or cessation of a core.
Without a magnetic field, life as we know it simply wouldn't be possible.
Mars is dead and Earth is alive. We're driven to understand the planet because humanity has restless eyes. There is something compelling about having a neighbour that has lived but has died. There are a lot of unanswered questions. For reasons we might not see in the present, understanding Mars could be critical if we want to live on it in the distant future.
Understanding Mars' magnetic field, how it evolved, and at which stage of the planet's history it stopped is important for future missions and is critical if scientists one day hope to establish human life on Mars.
All Rights Reserved © 2024
