Jupiter's huge moon Ganymede may have the largest impact scar in the solar system

[Admin]

Scientists have discovered what they believe may be the largest impact crater in the entire solar system, with scars covering a vast portion of Jupiter's huge moon, Ganymede.

Jupiter's huge moon Ganymede may have the largest impact scar in the solar system : Read more

 

[Don M]

Hmmm, according to this article and the statement from Kobe University, the impact on Ganymede precedes the formation of both our Solar System and our Universe: 40 billion years(!). Need some better editors.

 

[rod]

FYI, I checked another report on this. The 40 billion years is there too. 'Huge ring-like structure on Ganymede's surface may have been caused by violent impact', https://phys.org/news/2020-08-huge-ring-like-ganymede-surface-violent.html, "It is believed that such an impact occurred around 40 billion years ago."

Okay, this is easy to explain. We have another object and event dated older than the universe age in the BB model, the Hubble time This happens from time to time in dating methods

 

[Mercury 3488]

Not only the 40 billion year gaff, but also I thought that the Utopia Planitia on Mars was the previously largest known impact basin in the solar system????

Within the Jovian system, yes the Valhalla Basin on Callisto was the previously known largest or even among any of the moons in our Solar System.

 

[RRG]

Maybe it was from a impact like an impact in your windshield and over time keeps getting bigger and bigger. Flexing vibrations and definitely gravity from that enormous planet Jupiter just continued to make it longer over many years. That would make it appear like the initial impact made it. Just a thought.

 

[Larry L]

The diameter of Ganymede is 5,270 km, so its circumference is 16,500 km. How can you have a crater on it with a radius of 7,800 km (diameter of 15,600 km), their largest estimate? Also, the "usual" ratio of crater diameter to impactor diameter is 10 or 20 to 1 and is very velocity-dependent. With their biggest impactor being 150 km in diameter, that gives you a maximum crater diameter of 3,000 km. You would expect impacts at the distance of Jupiter to be lower than near Earth, but I guess they can be higher if the impactor got a velocity boost by Jupiter (slingshot effect). I am adding this a few minutes later, They have the RADIUS of the impactor being 150 km, so the maximum crater diameter would be 6,000 km or so, depending on the velocity of the impactor (20 km/sec seems high for this distance from the Sun.).

 

[Catastrophe]

Here is the (previous) list:

https://en.wikipedia.org/wiki/List_of_largest_craters_in_the_Solar_System

 

[rod]

FYI. The 40 billion years problem is 40 million years ago according to this report. That somewhat aligns with Saturn ring system ages said to be perhaps 100 million years old (according to some sources). 40 million years ago shows a younger age for some large impacts still taking place in the solar system. "The research team conducted a simulation to estimate the scale of the impact that formed this giant crater. This was carried out using the "PC Cluster" at the National Astronomical Observatory of Japan (NAOJ). The results indicated that an asteroid with a radius of 150km impacting Ganymede at a speed of 20km/s would be sufficient to form the observed structures on the satellite's surface. It is believed that such an impact occurred around 40 million years ago.", Huge ring-like structure on Ganymede's surface may have been caused by violent impact, https://www.sciencedaily.com/releases/2020/08/200807102339.htm

 

[Mercury 3488]

rod. Ganymede orbits Jupiter, not Saturn. I think the article meant 4 billion years old.

I am not so sure that impacts necessarily explains Ganymede's internal differentiaton as opposed to Callisto's homogeny. Ganymede certainly formed closer to Jupiter than Callisto, where there would be a greater abundance of heavier elements. Ganymede certainly has more iron internaly than Callisto.

There appears to have been enough iron to form an inner iron rich core and an outer iron sulphide outer core like the Earth and Mercury (Ganymede is unique among the solar system moons to have a dual layered core). This separation would have generated enough heat for the layers to form within Ganymede.

Europa and Io are also very heavily differentiated, though they both appear to have singular layered cores, so this makes sense.

Does not mean though Ganymede did not have enormous impacts though.

 

[rod]

FYI. The sciencedaily.com report says very clearly 40 million years ago and I see no other sources claiming to correct the time of impact to 4 billion years ago. I pointed out Saturn ring age here for thought and comparison with impact(s) at Ganymede dated much younger. if the Ganymede impact took place 40 million years ago and Saturn's rings are indeed quite young relative to geologic ages, that indicates there was recent catastrophism in our solar system. If there is evidence in our solar system for recent catastrophism that took place <= 100 million years ago, that should be clearly documented and pointed out to the public.

 

[Catastrophe]

Rod
The rings of Saturn lie inside Saturn's Roche limit and may be the debris of a demolished moon. Would you necessarily include this as catastrophism (which would include impact)?

 

[rod]

Rod
The rings of Saturn lie inside Saturn's Roche limit and may be the debris of a demolished moon. Would you necessarily include this as catastrophism (which would include impact)?

Yes, especially if the rings formed much more recently in relation to the geologic ages vs. the protoplanetary disk model. Ganymede large impact now could be 40 million years ago according to the sciencedaily.com report. I will wait and see here. The more younger impacts, young ring ages, etc. are established relative to the geologic ages, the more likely there was catastrophism in many areas of the solar system - much more recently than presently acknowledged in the protoplanetary disk model.

 

[Catastrophe]

FYI. The sciencedaily.com report says very clearly 40 million years ago and I see no other sources claiming to correct the time of impact to 4 billion years ago. I pointed out Saturn ring age here for thought and comparison with impact(s) at Ganymede dated much younger. if the Ganymede impact took place 40 million years ago and Saturn's rings are indeed quite young relative to geologic ages, that indicates there was recent catastrophism in our solar system. If there is evidence in our solar system for recent catastrophism that took place <= 100 million years ago, that should be clearly documented and pointed out to the public.

Agreed.

 

[Torbjorn Larsson]

The diameter of Ganymede is 5,270 km, so its circumference is 16,500 km. How can you have a crater on it with a radius of 7,800 km (diameter of 15,600 km), their largest estimate? Also, the "usual" ratio of crater diameter to impactor diameter is 10 or 20 to 1 and is very velocity-dependent. With their biggest impactor being 150 km in diameter, that gives you a maximum crater diameter of 3,000 km. You would expect impacts at the distance of Jupiter to be lower than near Earth, but I guess they can be higher if the impactor got a velocity boost by Jupiter (slingshot effect). I am adding this a few minutes later, They have the RADIUS of the impactor being 150 km, so the maximum crater diameter would be 6,000 km or so, depending on the velocity of the impactor (20 km/sec seems high for this distance from the Sun.).

Yes, and the quoted impact list implies another gaffe - they likely meant diameter. I'm not that interested to look at the paper, but maybe you are.

if the Ganymede impact took place 40 million years ago and Saturn's rings are indeed quite young relative to geologic ages, that indicates there was recent catastrophism in our solar system. If there is evidence in our solar system for recent catastrophism that took place <= 100 million years ago, that should be clearly documented and pointed out to the public.

Well, it is and it isn't - the very public Chicxulub impactor that ushered in a new ecology is 66 Myrs old. But "catastrophism" in the old geological sense it isn't, we have had many big mass extinctions.

The outer moon systems are dynamical. No surprise since the whole system is, only general relativity has lowered the instability rate sufficiently for us to retain the original planets thus far [ http://www.scholarpedia.org/article/Stability_of_the_solar_system ]. But the reverse side of the coin is that we don't see any general problem (as per the mass extinction record or the low instability rate).

I'm not sure what fishing expedition your are out on; this has, say, nothing to do with the protoplanetary disk model which covered the first 10-100 million year (likely the former) of the system lifetime. [And, I'm not sure you read my comment elsewhere, but the usual plaint of yours of low disk masses in such models has potentially been solved: https://www.sciencemag.org/news/2020/06/missing-mass-planet-formation-found-young-disks-gas-and-dust . Solving ever more problems means the theory is useful and robust.]

 

[rod]

FYI. There is no fishing trip here Torbjorn (ref post #14). The report provided 40 billion years ago for the impact at Ganymede in two different sources, another source shows 40 million years ago, and your comments fail to report a new time for this Ganymede impact model event or show the 40 million year age in sciencedaily.com report is false. The protoplanetary disk is dated to 4.568E+9 billion years ago as tiny dust grains before any planets formed around the early Sun. See 'The age of the Solar System redefined by the oldest Pb-Pb age of a meteoritic inclusion', https://ui.adsabs.harvard.edu/abs/2010NatGe...3..637B/abstract, "The age of the Solar System can be defined as the time of formation of the first solid grains in the nebular disc surrounding the proto-Sun. This age is estimated by dating calcium-aluminium-rich inclusions in meteorites."

I am contrasting different ages reported for the past history of the evolution of the solar system. If our solar system has large impacts taking place along with young ring system ages that formed <=100 million years ago, this should be acknowledged and not efforts that seem to obfuscate important issues in possible, solar system *evolution*, especially if it involves recent catastrophism relative to the dating of the protoplanetary disk with tiny dust grains in it and the geologic ages. Concerning reports of dust and gas disk masses around various stars seen today containing not enough dust, gas and low masses reported that I have documented at times, different reports do not support current accretion models as some of your posts claim the observations do. It is apparent that different reports indicate that the protoplantary disks models are not as robust as commonly thought with challenges too. I am not claiming the disks models are all wrong but the observations do not present *a clean bill* submitted to the President for signing either

"...But disks are not necessarily as neatly arranged as these initial dust observations suggest. A new ALMA image of RU Lup, a young variable star in the Lupus constellation, revealed a giant set of spiral arms made of gas, extending far beyond its more well-known dust disk. This spiral structure—resembling a 'mini-galaxy' - extends to nearly 1000 astronomical units (au) from the star, much farther away than the compact dust disk that extends to about 60 au...In recent years, high resolution observations of dust structures have revolutionized our understanding of planet formation. However, this new image of the gas indicates that the current view of planet formation is still too simplistic and that it might be much more chaotic than previously inferred from the well-known images of neatly concentric ringed disks. "The fact that we observed this spiral structure in the gas after a longer observation suggests that we have likely not seen the full diversity and complexity of planet-forming environments. We may have missed much of the gas structures in other disks," added Huang.", ref - ALMA captures stirred-up planet factory, https://phys.org/news/2020-08-alma-captures-stirred-up-planet-factory.html

 

[Mercury 3488]

40 million years old, complete and utter garbage. This FFI (Furrow Forming Impact) took place no less than 3.8 billion years ago, towards the end of the Late Heavey Bombardment and possibly a little earlier.
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From Icarus:
"Because furrows are crosscut by any recognizable impact craters exceeding 10 km in diameter, they are regarded as the oldest recognizable surface features on Ganymede ".

"If furrows are created by an impact, this large impact should have affected the geology of Ganymede significantly. It is known that the crater density in most heavily cratered terrains of Ganymede is slightly lower than that of Callisto (Strom et al., 1981). Such old craters are considered to be formed during the Late Heavy Bombardment (LHB, 4.1–3.8 Ga), according to the so-called Nice model (Gomes et al., 2005). Perhaps, the FFI would have taken place during the LHB, would have reset the crater age of Ganymede, and would be responsible for the difference in the crater densities between Ganymede and Callisto."
_______________________________________________________________________________________________________

Whoever dreamt up only 40 million years (one of the funniest things I've heard for a long time) has no real idea about Planetary Science.

The Space Daily site really needs to proof read it's articles before they are published or it will be ridiculed for publishing junk science.

The impact feature is largely buried under thousands of other craters and where it is visible, is on terrain so old, that it has been radiation darkened and pitted by millions of tiny impacts, not to mention rearranged by more recent faulting and geological activity on Ganymede.

If this was only 40 million years old, then this feature would be so fresh, it would have been discovered from Voyager 1 images and the impact site would be very clearly visible, not nearly 40 years later after years of research and more recent Galileo images and still the impact site has not been found.

Perhaps the upcoming ESA JUICE and NASA Europa Clipper missions will find the impact site (assuming it still exists after all this time).

I have no doubt about the youth of Saturn's rings as evidence points to their youth, but this feature on Ganymede is so old, it has taken years to find it, Also many part's of Ganymede's surface has shifted, so the pieces found do not even all line up. It will be a nice project for someone to try and join up the pieces found so far.

 

[rod]

FYI. Two sources cited 40 billion years ago, space.com and phys.org. sciencedaily.com reported 40 million years ago. 40E+9, 40E+6, 4E+9, it is just some exponents folks

 

[Alfred Herman Schrader]

Scientists have discovered what they believe may be the largest impact crater in the entire solar system, with scars covering a vast portion of Jupiter's huge moon, Ganymede.

Jupiter's huge moon Ganymede may have the largest impact scar in the solar system : Read more

Scientists have discovered what they believe may be the largest impact crater in the entire solar system, with scars covering a vast portion of Jupiter's huge moon, Ganymede.

Jupiter's huge moon Ganymede may have the largest impact scar in the solar system : Read more

Impacts are how our Solar System is being built, case in point recent 11 impacts on Jupiter. Our Solar System is not billions of years old. Most of the stuff floating around in the universe is. For example our moon is made of dust and meteors some of which have been floating in space for billions of years. If you carbon date material from the surface of the moon, it "tests" billions of years old but the moon itself is new same as the rest of the planets, moons, and our star. Find this by flipping E = mc² to mc² = E

 

[Catastrophe]

Sorry to clarify, but don't you mean something other than C which is only good for a few tens of thousand years?
"If you carbon date material from the surface of the moon, it "tests" billions of years old"