Intro: A proposal, musing, or [/b]speculation[/b]
DOES NOT QUALIFY AS A DISCOVERY
A 'giant subterranean ocean on Mars' has NOT been 'discovered'.
First, the TITLE -
Hidden Ocean Beneath Mars: A Game-Changing Discovery
Exhibit A: Jim Green (NASA’s Chief Scientist): “A subsurface ocean on Mars could serve as a vast reservoir of life, protected from the harsh surface conditions. This possibility is an exciting reminder that we still have much to learn about our neighboring planet.” (Jim Green, 2020, reflecting on the potential for subsurface water on Mars)
Count the HEDGE words in Mr. Green's statement immediately after the Title. could, possibility, reflecting, potential for ....
A more accurate term than 'reflecting on' would have been a TRUTHFUL statement "speculating on", because that is exactly what it is: rank speculation - not a reflection - reflection requires existence, speculation can be about anything. Even 'thoughts on' is a more explicit admission than deflecting with 'reflecting'. Obfuscation, concealment with at best, ambiguous words.
Now, the GUTS of the ISSUE - the actual 'scientific' methods used to bolster such a 'gigantic speculation'.
Past the fraudulent hype of the article, a bit of the 'methodology' is revealed, buried well into the article.
From the article ...
By analyzing the speed of seismic waves traveling through the Martian crust, researchers were able to infer the presence of substances beneath the surface. The speed of these waves can reveal the composition of the rock, its fractures, and what fills those cracks. Utilizing this data, Wright and his team fed the information into a rock physics model—similar to methods used on Earth to locate oil fields and aquifers.
Their findings indicate that the data best aligns with a deep layer of volcanic rock, saturated with liquid water. Study coauthor Michael Manga, a professor of earth and planetary science at the University of California, Berkeley, suggested that this discovery offers a glimpse into Mars’ past climate and the potential habitability of its deep subsurface.
The study authors propose that if Mars’ crust is similar across the planet, the mid-crust zone might contain even more water than previously hypothesized ancient Martian oceans. This discovery enriches our understanding of Mars’ water cycle and its geological evolution.
... end excerpt
Not much there really about the facts or really even about the method.
1. Igneous, possibly some metamorphic, rocks are all that exist on mars. Layered sedimentary rocks DO NOT.
2. Igneous (volcanic) mineral are dense, and have high seismic velocities. Microfracturing will reduce both shear and pressure waves (S & P waves). The presence or absence of fluid in the microfractures will have VERY LITTLE, IF ANY effect on the velocity of either P or S waves in such a medium - (microfractured igneous rocks). That is field proven, and laboratory experiment verified FACT. The mineralogical composition DOES have an observable effect - ie. quart vs granite vs other 'igneous' rocks. These velocities are in RANGES for different compositions - they are NOT 'single fixed values' - depending on several variables; mineral composition, direction of wave wrt stress vectors, extent of microfracturing, size of microfracturing, and son on.
As for those 'models' that the article references: On which geologic samples (ie. rocks) from Mars were those models based ?
Some educated infernals about variosus aspects;
1. Reciever; stationary (known), probably tri-axial (x,y, and z independent measurements), if an array (ie. multiple recievers) would have relatively small spatial array. Ie. VERY limited 'seismic' measurement capabilities - but the BEST that could be done with the size and location limitations on such a mission.
2. Source: undoubtedly the 'quakes and microquakes' generated by Mars itself. A controlled source would require far too much energy for prolonged measurements and the touted 12-15 mile deep 'investigation' claim.
This means that the SOURCE location(s) were unknown and variable *not all quakes from exactly the same location, obviously*, of extreme variable frequency and amplitude/magnitude, depths unknown, and so forth. Those type of determinations require MULTIPLE receiver stations, separated by large (miles to hundreds or even thousands of miles) distances. Thus, the 'inferred' nature of the seimic 'source(s)'.
3. Most of the seismic measured would be either direct arrivals or refracted energy. Perhaps SOME reflected would have been received (layered lava flows on the surface, magma pipes, or other volcanic features).
I could go on, but the number of UNKNOWNS in all of this are really HIGH. There is no way that they have scientifically proven (ie. discovered) anything 12-15 miles below the surface of mars - much less a 'submerged ocean'.
Scripps HAS had a pretty impressive record to date. This article however, and presentation of blatant speculations touting a 'DISCOVERY' is not only extremely disappointing, it tarnishes that reputation greatly, and lowers their involment to the level of Barnum and Baily carnival barkers.
And yes, there are MANY other types of 'seismic' waves. And no, shear waves CAN NOT travel through a fluid. But they CAN and DO travel easily through strata that are microfractured and contain fluids. You still have solids touching solids in that media.
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