APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

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APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by APOD Robot » Sat Mar 23, 2024 1:45 pm

Image Ares 3 Landing Site: The Martian Revisited

Explanation: This close-up from the Mars Reconnaissance Orbiter's HiRISE camera shows weathered craters and windblown deposits in southern Acidalia Planitia. A striking shade of blue in standard HiRISE image colors, to the human eye the area would probably look grey or a little reddish. But human eyes have not gazed across this terrain, unless you count the eyes of NASA astronauts in the scifi novel The Martian by Andy Weir. The novel chronicles the adventures of Mark Watney, an astronaut stranded at the fictional Mars mission Ares 3 landing site corresponding to the coordinates of this cropped HiRISE frame. For scale Watney's 6-meter-diameter habitat at the site would be about 1/10th the diameter of the large crater. Of course, the Ares 3 landing coordinates are only about 800 kilometers north of the (real life) Carl Sagan Memorial Station, the 1997 Pathfinder landing site.

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zendae1

Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by zendae1 » Sat Mar 23, 2024 3:30 pm

Well, since no one has posted a reply today, I'll just offer that any APOD explanation that has Carl Sagan's name in it, I love.

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Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by Rauf » Sat Mar 23, 2024 4:23 pm

zendae1 wrote: Sat Mar 23, 2024 3:30 pm Well, since no one has posted a reply today, I'll just offer that any APOD explanation that has Carl Sagan's name in it, I love.
New APOD is typically released at midnight EST, but today for some reason it has been delayed. Maybe that's why no one has commented yet.

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Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by johnnydeep » Sat Mar 23, 2024 5:11 pm

APOD Robot wrote: Sat Mar 23, 2024 1:45 pm Image Ares 3 Landing Site: The Martian Revisited

Explanation: This close-up from the Mars Reconnaissance Orbiter's HiRISE camera shows weathered craters and windblown deposits in southern Acidalia Planitia. A striking shade of blue in standard HiRISE image colors, to the human eye the area would probably look grey or a little reddish. But human eyes have not gazed across this terrain, unless you count the eyes of NASA astronauts in the scifi novel The Martian by Andy Weir. The novel chronicles the adventures of Mark Watney, an astronaut stranded at the fictional Mars mission Ares 3 landing site corresponding to the coordinates of this cropped HiRISE frame. For scale Watney's 6-meter-diameter habitat at the site would be about 1/10th the diameter of the large crater. Of course, the Ares 3 landing coordinates are only about 800 kilometers north of the (real life) Carl Sagan Memorial Station, the 1997 Pathfinder landing site.
So why do the HiRISE images appear bluish? I presume it isn't because it's imaging southern "arctic" snow and ice!

And the large crater is about 60 m in diameter? Somehow that seems too small based on all the much smaller craters.
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Roy

Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by Roy » Sat Mar 23, 2024 5:39 pm

I love a good Martian sci-fi story, too, featuring the incomparable Dejah Thoris, princess of Helium, and Tars Tarkas, Jeddak of Thark. But when humans get to Mars, it will probably be after we figure out how the UFOS do it. Here are the problems to consider:
Gravity is 38% of Earth gravity.
Atmosphere is equivalent to earth’s pressure at 116,500 feet altitude, is 95% carbon dioxide, no oxygen, no water, very little nitrogen, and varies up to 25% in pressure due to freezing and thawing of dry ice polar caps.
Surface temperature varies from 32 F down to -103 F.

One good thing, is the presence of dust devils and dust storms. This indicates the presence of electricity - I suspect Mars sweeps up solar electrons, just as the Earth does (magnetically channeled into auroras). The absence of a thick atmosphere probably likens the surface to a continual “Carrington Event “, and electrical power in plenty can be extracted from it. All other problems then become solvable.

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Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by johnnydeep » Sat Mar 23, 2024 6:04 pm

Roy wrote: Sat Mar 23, 2024 5:39 pm I love a good Martian sci-fi story, too, featuring the incomparable Dejah Thoris, princess of Helium, and Tars Tarkas, Jeddak of Thark. But when humans get to Mars, it will probably be after we figure out how the UFOS do it. Here are the problems to consider:
Gravity is 38% of Earth gravity.
Atmosphere is equivalent to earth’s pressure at 116,500 feet altitude, is 95% carbon dioxide, no oxygen, no water, very little nitrogen, and varies up to 25% in pressure due to freezing and thawing of dry ice polar caps.
Surface temperature varies from 32 F down to -103 F.

One good thing, is the presence of dust devils and dust storms. This indicates the presence of electricity - I suspect Mars sweeps up solar electrons, just as the Earth does (magnetically channeled into auroras). The absence of a thick atmosphere probably likens the surface to a continual “Carrington Event “, and electrical power in plenty can be extracted from it. All other problems then become solvable.
I believe dust storms and dust devils on Mars are caused by the same thing that causes them on Earth, namely wind:
https://en.wikipedia.org/wiki/Dust_devil#Formation wrote: Formation

Dust devils form when a pocket of hot air near the surface rises quickly through cooler air above it, forming an updraft. If conditions are just right, the updraft may begin to rotate. As the air rapidly rises, the column of hot air is stretched vertically, thereby moving mass closer to the axis of rotation, which causes intensification of the spinning effect by conservation of angular momentum. The secondary flow in the dust devil causes other hot air to speed horizontally inward to the bottom of the newly forming vortex. As more hot air rushes in toward the developing vortex to replace the air that is rising, the spinning effect becomes further intensified and self-sustaining.[3] A dust devil, fully formed, is a funnel-like chimney through which hot air moves, both upwards and in a circle. As the hot air rises, it cools, loses its buoyancy and eventually ceases to rise. As it rises, it displaces air which descends outside the core of the vortex. This cool air returning acts as a balance against the spinning hot-air outer wall and keeps the system stable.[4]

The spinning effect, along with surface friction, usually will produce a forward momentum. The dust devil may be sustained if it moves over nearby sources of hot surface air.[5]
Last edited by johnnydeep on Sat Mar 23, 2024 7:06 pm, edited 1 time in total.
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Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by Chris Peterson » Sat Mar 23, 2024 6:26 pm

Roy wrote: Sat Mar 23, 2024 5:39 pm I love a good Martian sci-fi story, too, featuring the incomparable Dejah Thoris, princess of Helium, and Tars Tarkas, Jeddak of Thark. But when humans get to Mars, it will probably be after we figure out how the UFOS do it. Here are the problems to consider:
Gravity is 38% of Earth gravity.
Atmosphere is equivalent to earth’s pressure at 116,500 feet altitude, is 95% carbon dioxide, no oxygen, no water, very little nitrogen, and varies up to 25% in pressure due to freezing and thawing of dry ice polar caps.
Surface temperature varies from 32 F down to -103 F.

One good thing, is the presence of dust devils and dust storms. This indicates the presence of electricity - I suspect Mars sweeps up solar electrons, just as the Earth does (magnetically channeled into auroras). The absence of a thick atmosphere probably likens the surface to a continual “Carrington Event “, and electrical power in plenty can be extracted from it. All other problems then become solvable.
Dust storms on Mars have nothing do do with electricity. But like dust storms on Earth, they can separate charge and create lighting.
Chris

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Roy

Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by Roy » Sat Mar 23, 2024 6:58 pm

Dust particles pick up electrons, hence electrostaticly repel each other, and can stay suspended and blow around. They become a moving charge in a magnetic field, subject to the “right hand rule” and circulate. In a dust storm you can feel the electricity. Heat does the drying out of the dust, maybe some rising air motion.

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Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by JohnD » Sat Mar 23, 2024 8:13 pm

Quote today's blurb, "the scifi novel The Martian by Andy Weir."

AND one the the best SF films in years. With an excellent cast, not least Mat Damon, as the "Martian".

As for " Dejah Thoris, princess of Helium, and Tars Tarkas, Jeddak of Thark" this film (and book!) will science the shit out of those fantasies!
John

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Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by Christian G. » Sat Mar 23, 2024 8:35 pm

zendae1 wrote: Sat Mar 23, 2024 3:30 pm Well, since no one has posted a reply today, I'll just offer that any APOD explanation that has Carl Sagan's name in it, I love.
I share your feeling! There have been lots of great astronomers and astrophysicists, but Carl Sagan is in a class of his own! We're lucky this man existed.
Last edited by Christian G. on Sun Mar 24, 2024 1:05 pm, edited 1 time in total.

Roy

Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by Roy » Sat Mar 23, 2024 9:09 pm

JohnD wrote: Sat Mar 23, 2024 8:13 pm Quote today's blurb, "the scifi novel The Martian by Andy Weir."

AND one the the best SF films in years. With an excellent cast, not least Mat Damon, as the "Martian".

As for " Dejah Thoris, princess of Helium, and Tars Tarkas, Jeddak of Thark" this film (and book!) will science the shit out of those fantasies!
John
Maybe so. But Burroughs wrote his story in 1911 for entertainment. We knew a lot less about planets then. We have an airless rock, a gas midget, a water world with a large moon, a rocky world with two captured fragments as moons, a raft of fragments, four gas giants, another airless rock with a large moon, and some things we are not sure about. We scienced a lot since ERB was writing.

I notice no one wants to address the problems I presented, except to deny that electricity does anything. As an interesting fact, one of the early space station experiments was to let out a length of wire to dangle. It was burned off by current.

zendae1

Re: APOD: Ares 3 Landing Site: The Martian... (2024 Mar 23)

Post by zendae1 » Sun Mar 24, 2024 4:08 pm

Christian G. wrote: Sat Mar 23, 2024 8:35 pm
zendae1 wrote: Sat Mar 23, 2024 3:30 pm Well, since no one has posted a reply today, I'll just offer that any APOD explanation that has Carl Sagan's name in it, I love.
I share your feeling! There have been lots of great astronomers and astrophysicists, but Carl Sagan is in a class of his own! We're lucky this man existed.
We saw our precious jewel like we have never seen before because of this extraordinary, prescient humanitarian, so full of love for all life. Nothing else in science has ever caused this commenter to....you know the rest.