APOD: Close Mars (2018 Aug 31)

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APOD: Close Mars (2018 Aug 31)

Post by APOD Robot » Fri Aug 31, 2018 4:05 am

Image Close Mars

Explanation: Still bright in evening skies, Mars was just past opposition and closest to Earth on July 31, a mere 57.6 million kilometers away. Captured only a week later, this remarkable image shows the Red Planet's disk near its maximum size in earthbound telescopes, but still less than 1/74th the apparent diameter of a Full Moon. Broad regional surface shadings are starting to reappear in the tantalizing view as the latest planet-wide dust storm subsides. With the bright south polar cap at the bottom, the Valles Marineris extends along the center of the disk. Just below it lies the roughly circular Solis Lacus region sometimes known as the Eye of Mars. In a line, three prominent dark spots left of center are the volcanic Tharsis Montes.

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Re: APOD: Close Mars (2018 Aug 31)

Post by Boomer12k » Fri Aug 31, 2018 5:59 am

I thought I could see more detail the other night, but was not sure as I was looking through some trees, but now that it seems to be clearer I will try to get a shot of it.
Now if "Oregon Weather" will just co-operate...

This shot was from earlier the 26th of July...just barely some detail.
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Re: APOD: Close Mars (2018 Aug 31)

Post by Sa Ji Tario » Fri Aug 31, 2018 1:13 pm

¡Awesome! ¡good shot!

Sa Ji Tario

Re: APOD: Close Mars (2018 Aug 31)

Post by Sa Ji Tario » Fri Aug 31, 2018 2:06 pm

I propose a logic game.-
Suppose we can bring the intact Earth to Mount Olympus (more than 24,000 meters high) and deposit it on the surface at sea level remembering that its base is about 600 km in diameter. It will begin then, a fight between the terrestrial gravity and the Martian density that when they were balanced would be a landscape different from the Martian and a new one in our planet. It will be a few hills of little more than 600 x 650 km and with maximum heights that would not exceed 4,000 meters. Earth's gravity would disintegrate and collapse the walls of Mount Olimpus and lateral plains and compress them until densifying them to the terrestrial tenor and always to my knowledge and understanding and subject to correction and discussion

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Re: APOD: Close Mars (2018 Aug 31)

Post by suicidejunkie » Fri Aug 31, 2018 3:23 pm

That's not a logic game.
That's a thought experiment.

I'm not sure what you're trying to do with it however.

If you're letting the planets go from a standstill, the surface features at the contact point on both sides would just get subsumed into part of the core as it all slumps together into a new sphere, and the details there would be pretty meaningless.
You'd probably have some features on the far side of each survive somewhat, but with the crust getting distorted as it changes shape like playdoh and magma splashing everywhere, it might not be recognizable. And there would definitely be a lot of freshly melted crust in a big fat band at the interface.

(It would probably be better to consider putting Earth on the far side from Mount Olympus and getting a computer sim run to see how recognizable the mountain is after the merger.
You might also try running a high speed camera and filming two odd-sized water drops merging (one with red dye and a bigger one with blue) and see where the colors go as they merge; that would be cool to see.)


If you're just applying a magical gravitational force from a point above M.O., then Mars would orbit it. It would still get distinctly and quickly squished away from round by the tidal forces. It depends on how far the gravity source is, but it sounds like you'd have mars well within the Roche limit, so the loose sand and rocks and atmosphere would peel off, and eventually you'd have a ring system and a large moon getting slowly chipped away instead of a planet.

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Re: APOD: Close Mars (2018 Aug 31)

Post by BillBixby » Fri Aug 31, 2018 5:14 pm

A mission must be sent to Mars to paint a big number 5 on the white spot!

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Re: APOD: Close Mars (2018 Aug 31)

Post by Ann » Fri Aug 31, 2018 6:14 pm

Boomer12k wrote:
Fri Aug 31, 2018 5:59 am
I thought I could see more detail the other night, but was not sure as I was looking through some trees, but now that it seems to be clearer I will try to get a shot of it.
Now if "Oregon Weather" will just co-operate...

This shot was from earlier the 26th of July...just barely some detail.
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It's a nice APOD, and I like your orange in the sky, Boomer.

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Sa Ji Tario

Re: APOD: Close Mars (2018 Aug 31)

Post by Sa Ji Tario » Fri Aug 31, 2018 8:25 pm

Friend Suicidiejunke there is an error in trtraduction that I did not notice. What I propose is to BRING THE MOUNT OLIMPUS UNTIL THE TTIERRA and proceed

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Re: APOD: Close Mars (2018 Aug 31)

Post by Chris Peterson » Fri Aug 31, 2018 9:02 pm

Sa Ji Tario wrote:
Fri Aug 31, 2018 2:06 pm
I propose a logic game.-
Suppose we can bring the intact Earth to Mount Olympus (more than 24,000 meters high) and deposit it on the surface at sea level remembering that its base is about 600 km in diameter. It will begin then, a fight between the terrestrial gravity and the Martian density that when they were balanced would be a landscape different from the Martian and a new one in our planet. It will be a few hills of little more than 600 x 650 km and with maximum heights that would not exceed 4,000 meters. Earth's gravity would disintegrate and collapse the walls of Mount Olimpus and lateral plains and compress them until densifying them to the terrestrial tenor and always to my knowledge and understanding and subject to correction and discussion
I'm guessing you're considering what would happen if a structure like Olympus Mons were on Earth. In fact, I don't think it would be dynamically unstable. Of course, it would erode away over time, but rock is strong enough to support a cone 600 km in diameter and 24 km high without collapsing under its own weight on Earth. There are reasons, related to the strength of gravity, why such a structure might not be able to form volcanically on Earth, but not why it couldn't exist if it were magically transported here. It might well collapse somewhat as the underlying continental crust deforms down into the mantle. The degree of collapse in that case would depend upon the thickness of that crust and the properties of the underlying mantle. And it would be slow- thousands or tens of thousands of years, at least.
Chris

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Re: APOD: Close Mars (2018 Aug 31)

Post by De58te » Fri Aug 31, 2018 9:20 pm

It may have been said before, but I noticed that Mars happened to have a planet wide dust storm around the same time it made the closest approach to the Earth.At the same time it makes the closest approach to Earth I suppose it makes the closest approach to the Sun as well. This must mean that more solar energy hits Mars perhaps causing the dust storm. The Earth of course helps out by being the farthest away from the Sun in July, which probably is why the Earth and Mars make such a close approach. So just wondering having read astrology where the planets have influence on each other, that the presence of the Earth had a cause for the Mars dust storm. Ie would Mars have the same global dust storm closest to the Sun even if the Earth would be on the other side of the Sun in its orbit?

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Re: APOD: Close Mars (2018 Aug 31)

Post by Chris Peterson » Fri Aug 31, 2018 9:52 pm

De58te wrote:
Fri Aug 31, 2018 9:20 pm
It may have been said before, but I noticed that Mars happened to have a planet wide dust storm around the same time it made the closest approach to the Earth.At the same time it makes the closest approach to Earth I suppose it makes the closest approach to the Sun as well.
When Earth and Mars are closest is unrelated to when Mars is closest to the Sun. The next martian perihelion will be on 16 September. Where both Mars and Earth are in their respective orbits (Mars's being more eccentric than Earth's) determines just how close the planets are to each other when they're at their nearest every couple of years. An opposition can occur when Mars is near perihelion, or near aphelion.

Martian weather is strongly impacted by orbital position (unlike Earth with its nearly circular orbit). So dust storms are more common near perihelion, and ice clouds are more common near aphelion (both having seasonal variations, as well, since Mars has a significant axial inclination). But because there's no relationship between when oppositions occur and when perihelions occur, we will, over time, observe dust storms both when Mars is near the Earth and when it is far away.
Chris

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Re: APOD: Close Mars (2018 Aug 31)

Post by neufer » Sat Sep 01, 2018 2:53 am

Click to play embedded YouTube video.
Chris Peterson wrote:
Fri Aug 31, 2018 9:02 pm

I'm guessing you're considering what would happen if a structure like Olympus Mons were on Earth. In fact, I don't think it would be dynamically unstable. Of course, it would erode away over time, but rock is strong enough to support a cone 600 km in diameter and 24 km high without collapsing under its own weight on Earth. There are reasons, related to the strength of gravity, why such a structure might not be able to form volcanically on Earth, but not why it couldn't exist if it were magically transported here. It might well collapse somewhat as the underlying continental crust deforms down into the mantle. The degree of collapse in that case would depend upon the thickness of that crust and the properties of the underlying mantle. And it would be slow- thousands or tens of thousands of years, at least.
A volcanic cone 600 km in diameter & 24 km high has a volume of around 3 million km3.

The Siberian Traps had a volume of around 4 million km3.
https://en.wikipedia.org/wiki/Siberian_Traps wrote: <<The Siberian Traps (Russian: Сибирские траппы, Sibirskiye trappy) is a large region of volcanic rock, known as a large igneous province, in Siberia, Russia. The massive eruptive event that formed the Traps is one of the largest-known volcanic events that has occurred in the last 500 million years.

The eruptions continued for roughly two million years and spanned the P–T boundary, or the Permian–Triassic boundary, which occurred between 251 to 250 million years ago.

Large volumes of basaltic lava covered a large expanse of Siberia in a flood basalt event. Today, the area is covered by about seven million km2 of basaltic rock, with a volume of around 4 million km3.>>
https://en.wikipedia.org/wiki/Hellas_Planitia wrote:

  • Olympus Mons: 18.65°N / 226.2°E
    Hellas Planitia: 42.4°S / 70.5°E
<<Hellas Planitia is a plain located within the huge, roughly circular impact basin Hellas located in the southern hemisphere of the planet Mars. Hellas is the third or fourth largest impact crater and the largest visible impact crater known in the Solar System. The basin floor is about 7,152 m deep, and extends about 2,300 km east to west. Hellas Planitia is thought to have been formed during the Late Heavy Bombardment period of the Solar System, approximately 4.1 to 3.8 billion years ago, when a large asteroid hit the surface.>>
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Re: APOD: Close Mars (2018 Aug 31)

Post by MarkBour » Sat Sep 01, 2018 4:56 am

Chris Peterson wrote:
Fri Aug 31, 2018 9:02 pm
Sa Ji Tario wrote:
Fri Aug 31, 2018 2:06 pm
I propose a logic game.-
Suppose we can bring the intact Earth to Mount Olympus (more than 24,000 meters high) and deposit it on the surface at sea level remembering that its base is about 600 km in diameter. It will begin then, a fight between the terrestrial gravity and the Martian density that when they were balanced would be a landscape different from the Martian and a new one in our planet. It will be a few hills of little more than 600 x 650 km and with maximum heights that would not exceed 4,000 meters. Earth's gravity would disintegrate and collapse the walls of Mount Olimpus and lateral plains and compress them until densifying them to the terrestrial tenor and always to my knowledge and understanding and subject to correction and discussion
I'm guessing you're considering what would happen if a structure like Olympus Mons were on Earth. In fact, I don't think it would be dynamically unstable. Of course, it would erode away over time, but rock is strong enough to support a cone 600 km in diameter and 24 km high without collapsing under its own weight on Earth. There are reasons, related to the strength of gravity, why such a structure might not be able to form volcanically on Earth, but not why it couldn't exist if it were magically transported here. It might well collapse somewhat as the underlying continental crust deforms down into the mantle. The degree of collapse in that case would depend upon the thickness of that crust and the properties of the underlying mantle. And it would be slow- thousands or tens of thousands of years, at least.
I think you're right in interpreting the thought experiment that Sa Ji Tario was proposing. And I'm guessing that he/she is making a conjecture that Olympus Mons, since it formed under Mars gravity, will be made of basalt that is less dense than the basalt that forms on Earth under our larger gravity. Or perhaps that the walls would be steeper or thinner than would be formed on Earth.

If so, I don't know if any of those would be true. If you take a pool of lava and let it flow down the side of a mountain under Mars' gravity, would it really form anything that is less dense, or would it form structures that were otherwise different in profile than it would on Earth? Or would it form essentially the same structure? From what little I know, I would expect it to be pretty much the same on either planet. It may well be that Sa knows something about this that I do not.
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Re: APOD: Close Mars (2018 Aug 31)

Post by Chris Peterson » Sat Sep 01, 2018 5:03 am

MarkBour wrote:
Sat Sep 01, 2018 4:56 am
Chris Peterson wrote:
Fri Aug 31, 2018 9:02 pm
Sa Ji Tario wrote:
Fri Aug 31, 2018 2:06 pm
I propose a logic game.-
Suppose we can bring the intact Earth to Mount Olympus (more than 24,000 meters high) and deposit it on the surface at sea level remembering that its base is about 600 km in diameter. It will begin then, a fight between the terrestrial gravity and the Martian density that when they were balanced would be a landscape different from the Martian and a new one in our planet. It will be a few hills of little more than 600 x 650 km and with maximum heights that would not exceed 4,000 meters. Earth's gravity would disintegrate and collapse the walls of Mount Olimpus and lateral plains and compress them until densifying them to the terrestrial tenor and always to my knowledge and understanding and subject to correction and discussion
I'm guessing you're considering what would happen if a structure like Olympus Mons were on Earth. In fact, I don't think it would be dynamically unstable. Of course, it would erode away over time, but rock is strong enough to support a cone 600 km in diameter and 24 km high without collapsing under its own weight on Earth. There are reasons, related to the strength of gravity, why such a structure might not be able to form volcanically on Earth, but not why it couldn't exist if it were magically transported here. It might well collapse somewhat as the underlying continental crust deforms down into the mantle. The degree of collapse in that case would depend upon the thickness of that crust and the properties of the underlying mantle. And it would be slow- thousands or tens of thousands of years, at least.
I think you're right in interpreting the thought experiment that Sa Ji Tario was proposing. And I'm guessing that he/she is making a conjecture that Olympus Mons, since it formed under Mars gravity, will be made of basalt that is less dense than the basalt that forms on Earth under our larger gravity. Or perhaps that the walls would be steeper or thinner than would be formed on Earth.

If so, I don't know if any of those would be true. If you take a pool of lava and let it flow down the side of a mountain under Mars' gravity, would it really form anything that is less dense, or would it form structures that were otherwise different in profile than it would on Earth? Or would it form essentially the same structure? From what little I know, I would expect it to be pretty much the same on either planet. It may well be that Sa knows something about this that I do not.
I don't think the rock would be substantially different in density or strength. I vaguely recall a nice analysis of how shield volcanoes form which (IIRC) concluded that it was not possible on Earth to produce one as large as Olympus Mons. But that's a different issue than the question of whether Olympus Mons, on Earth, would collapse under its own weight.
Chris

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Re: APOD: Close Mars (2018 Aug 31)

Post by MarkBour » Sat Sep 01, 2018 5:30 am

neufer wrote:
Sat Sep 01, 2018 2:53 am
(YouTube video about a large impact potentially causing a volcanic event on the antipode on a planet.)
... A volcanic cone 600 km in diameter & 24 km high has a volume of around 3 million km3.
... The Siberian Traps had a volume of around 4 million km3.
... Hellas Planitia ... is the third or fourth largest impact crater and the largest visible impact crater known in the Solar System.
Sometimes I need a little extra help, Art.

Are you pointing out that Hellas Planitia, which is evidently an impact basin, is sort of close to being antipodal to Olympus Mons on Mars? In which case they might be related?

Are you putting the Siberian traps up as an event whose outcome might help answer Sa Ji Tario's thought experiment?

(By the way, using V= πr2h/3, I come up with more like 2.2 million km3, but why quibble?)
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Re: APOD: Close Mars (2018 Aug 31)

Post by neufer » Sat Sep 01, 2018 11:48 am

neufer wrote:
Sat Sep 01, 2018 2:53 am

(YouTube video about a large impact potentially causing a volcanic event on the antipode on a planet.)
... A volcanic cone 600 km in diameter & 24 km high has a volume of around 3 million km3.
... The Siberian Traps had a volume of around 4 million km3.
... Hellas Planitia ... is the third or fourth largest impact crater and the largest visible impact crater known in the Solar System.
MarkBour wrote:
Sat Sep 01, 2018 5:30 am

Are you pointing out that Hellas Planitia, which is evidently an impact basin, is sort of close to being antipodal to Olympus Mons on Mars? In which case they might be related?
Absolutely :!:
MarkBour wrote:
Sat Sep 01, 2018 5:30 am
Are you putting the Siberian traps up as an event whose outcome might help answer Sa Ji Tario's thought experiment?
I'm putting the Siberian Traps up as, perhaps, the closest thing Earth has
ever had to Olympus Mons and tossing out a different thought experiment.

One could throw in the Deccan Traps as yet another member of the 'Von Traps' family:
https://en.wikipedia.org/wiki/Deccan_Traps wrote:
<<Deccan Traps are a large igneous province located on the Deccan Plateau of west-central India (17°–24°N, 73°–74°E) and are one of the largest volcanic features on Earth. They consist of multiple layers of solidified flood basalt that together are more than 2,000 m thick and have a volume of ~1,000,000 km3. There is some evidence to link the Deccan Traps eruption to the asteroid impact which created the Chicxulub crater (21.4°N, 89.5°W) in the Mexican state of Yucatán. Although the Deccan Traps began erupting well before the impact, argon-argon dating suggests that the impact may have caused an increase in permeability that allowed magma to reach the surface and produced the most voluminous flows, accounting for around 70% of the volume. The combination of the asteroid impact and the resulting increase in eruptive volume may have been responsible for the mass extinctions that occurred at the time that separates the Cretaceous and Paleogene periods, known as the K–Pg boundary.>>
MarkBour wrote:
Sat Sep 01, 2018 5:30 am

(By the way, using V= πr2h/3, I come up with more like 2.2 million km3, but why quibble?)
Olympus Mons is a rather obese cone so I rounded up.
Art Neuendorffer