APOD: Global Map: Mars at Opposition (2020 Nov 20)

[APOD Robot]

Global Map: Mars at Opposition

Explanation: This may be the best global Mars map made with a telescope based on planet Earth. The image data were captured by a team of observers over six long nights at the Pic du Midi mountaintop observatory between October 8 and November 1, when the fourth rock from the Sun had not wandered far from its 2020 opposition and its biggest and brightest appearance in Earth's night sky. The large telescope used, 1 meter in diameter with a 17 meter focal length, was also used in support of NASA's Apollo lunar landing missions. After about 30 hours of processing, the data were combined to produced this remarkably sharp projected view of the martian surface extending to about 45 degrees northern latitude. The image data have also been mapped onto a rotating sphere and rotating stereo, views. Fans of Mars can easily pick out their favorite markings on the Red Planet by eyeing a labeled version of this global map of Mars.

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[JohnD]

What marks the Martian meridian, 0 degrees longitude? How was it set?

[heehaw]

What marks the Martian meridian, 0 degrees longitude? How was it set?

https://www.esa.int/Science_Exploration ... de_on_Mars

[JohnD]

Thank you, heehaw! I am amazed that the originators were Beer and Madler in the middle of the 19th, but astronomers then needed a reference system too!

[neufer]

What marks the Martian meridian, 0 degrees longitude? How was it set?

https://www.esa.int/Science_Exploration ... de_on_Mars

Thank you, heehaw! I am amazed that the originators were Beer and Madler in the middle of the 19th, but astronomers then needed a reference system too!

Oasis in the Libyan part of the Sahara

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[This] song probably originated in Germany and was brought to America by immigrants. The word "derry" is the anglicization of the Old Irish Gaelic word Daire (in Modern Irish Gaelic Doire) which means oak grove and/or an area densely wooded with oak trees.

The farmer in the dell
The farmer in the dell
Hi-ho, the derry-o
The farmer in the dell

Annotated elevation map of Opportunity landing site and some surrounding craters including Endeavour and Airy.

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<<Airy-0 is a crater on Mars whose location defines the position of the prime meridian of that planet. It is about 0.5 kilometres across and lies within the larger crater Airy in the region Sinus Meridiani. The IAU Working Group on Cartographic Coordinates and Rotational Elements has now recommended setting the longitude of the Viking 1 lander (47°.95137 west) as the standard. This definition maintains the position of the center of Airy-0 at 0° longitude, within the tolerance of current cartographic uncertainties.

Merton Davies tied this crater into an extensive geodetic control network of the planet Mars based on Mariner 9 and earlier photographs. The Mariner 9 Geodesy/Cartography Group proposed that the prime meridian of Mars be defined by the center of Airy-0, which was selected by Harold Masursky, Gerard de Vaucouleurs, and Merton Davies at a Group meeting on 14 August 1972.

It was named in honor of the British Astronomer Royal Sir George Biddell Airy (1801–1892), who in 1850 built the transit circle telescope at Greenwich. The location of that telescope was subsequently chosen to define the location of Earth's prime meridian.

[orin stepanek]

Nice job; but I would be lost trying to find my way using this map if I were marooned on Mars! I loved the map on a rotating globe! Very neat!!!

[johnnydeep]

Thank you, heehaw! I am amazed that the originators were Beer and Madler in the middle of the 19th, but astronomers then needed a reference system too!

While searching for the "feature A" that Beer and Madler chose as the location of the Martian prime meridian, I found that this "circular feature" - which does not appear to be that circular! - is now referred to as Meridiani Planum. https://en.wikipedia.org/wiki/Mädler_(Martian_crater):

Mädler and collaborator Wilhelm Beer produced the first reasonably good maps of Mars in the early 1830s. When doing so, they selected a particular feature for the prime meridian of their charts. Their choice was strengthened when Giovanni Schiaparelli used the same location in 1877 for his more famous maps of Mars. The feature was later called Sinus Meridiani ("Middle Bay" or "Bay of the Meridian"), but following the landing of the NASA probe MER-B Opportunity in 2004 is perhaps better known as Meridiani Planum.

Mädler lies in the south of Meridiani Planum, close to the prime meridian and about 10° east of Beer. Schiaparelli is also in the region.

But since Meridiani Planum is not really well defined, it looks like some other convention was agreed upon as the exact location of the Martian prime meridian. Looking at this map from http://planetary-science.org/wp-content ... hoO4SV.jpg, I see one small crater in particular that seems lie almost exactly entered on the meridian at about -25 degrees south latitude:

http://planetary-science.org/wp-content ... hoO4SV.jpg

EDIT: I see that neufer beat me to the real answer of the Airy-0 crater's longitude being the true definition of the martian prime meridian.

[ And so sorry about the hot link to a "bigish" image...but 500KB is the limit? How draconian! ]

[BDanielMayfield]

But since Meridiani Planum is not really well defined, it looks like some other convention was agreed upon as the exact location of the Martian prime meridian. Looking at this map from http://planetary-science.org/wp-content ... hoO4SV.jpg, I see one small crater in particular that seems lie almost exactly entered on the meridian at about -25 degrees south latitude:

http://planetary-science.org/wp-content ... hoO4SV.jpg

Thanks for sharing that map with us johnnydeep. It needs a legend to explain all those colors though.

[bystander]

But since Meridiani Planum is not really well defined, it looks like some other convention was agreed upon as the exact location of the Martian prime meridian. Looking at this map from http://planetary-science.org/wp-content ... hoO4SV.jpg, I see one small crater in particular that seems lie almost exactly entered on the meridian at about -25 degrees south latitude:

http://planetary-science.org/wp-content ... hoO4SV.jpg

Thanks for sharing that map with us johnnydeep. It needs a legend to explain all those colors though.

Start here: https://pubs.usgs.gov/sim/3292/

[johnnydeep]

But since Meridiani Planum is not really well defined, it looks like some other convention was agreed upon as the exact location of the Martian prime meridian. Looking at this map from http://planetary-science.org/wp-content ... hoO4SV.jpg, I see one small crater in particular that seems lie almost exactly entered on the meridian at about -25 degrees south latitude:

http://planetary-science.org/wp-content ... hoO4SV.jpg

Thanks for sharing that map with us johnnydeep. It needs a legend to explain all those colors though.

Start here: https://pubs.usgs.gov/sim/3292/

Thanks! And from there you can get to what must be the mother of all single page PDFs, at 35 MB!

[neufer]

A new map of Barsoom by Oberon Zell

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Laser Altimeter Topographic Map over Shiaparelli’s 1886 Map

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Official Edgar Rice Burroughs Tribute and Weekly Webzine Site: Volume 3937

Upon the edges of plateaus that once had marked the shore-line of a noble continent I passed above the lonely monuments of that ancient prosperity, the sad, deserted cities of old Barsoom. Even in their ruins there is a grandeur and magnificence that still have power to awe a modern man. Down towards the lowest sea bottoms other ruins mark the tragic trail that that ancient civilization had followed in pursuit of the receding waters of its ocean to where the last city finally succumbed, bereft of commerce, shorn of power, to fall at last an easy victim to the marauding hordes of fierce, green tribesmen, whose descendants now are the sole rulers of many of those deserted sea bottoms.

<<Accurate placement of these ancient dead cities from the time of the Orovars required my creating an accurate map of ancient Mars/Barsoom with all those oceans in place. The great Hellas and Argyre Impacts that blew away most of the northern hemisphere, split open the Valles Marineris, and erupted all those immense volcanoes, are currently believed to have occurred around three billion years ago. Since Mars has no tectonic plates to move continents around and raise new mountain ranges, elevations would not have changed in the past several million years. Therefore I felt confident in using the MOLA Laser Altimeter Topographic Map of Mars to establish the basic sea-level (at MOLA’s 0-meter elevation) for the time of the Orovars. I superimposed the MOLA map over Shiaparelli’s 1886 Mercator projection map—which I turned over to place north at the top, and removed all of Shiaparelli’s place names.>>

[Peter Bradford]

Ooh! Looks like a canal!!

[neufer]

Ooh! Looks like a canal!!

<<The Pic du Midi Observatory (French: Observatoire du Pic du Midi) is an astronomical observatory located at 2877 meters on top of the Pic du Midi de Bigorre in the French Pyrenees. Construction of the observatory began in 1878 under the auspices of the Société Ramond, but by 1882 the society decided that the spiralling costs were beyond its relatively modest means, and yielded the observatory to the French state, which took it into its possession by a law of 7 August 1882.

The 8 metre dome was completed in 1908, under the ambitious direction of Benjamin Baillaud. It housed a powerful mechanical equatorial reflector which was used in 1909 to formally discredit the Martian canal theory.>>

[BDanielMayfield]

A lot of theories still need to be formally discredited.

[Chris Peterson]

A lot of theories still need to be formally discredited.

Not so many, I think. It's been a long time since any major theory was discredited. We seem to have a pretty good handle on nature now. A few important missing pieces, none of which have single, widely accepted theories. And an awful lot of stuff that is either complete, or probably subject to nothing but minor adjustments, not at all likely to be rejected.

[neufer]

A lot of theories still need to be formally discredited.

• I hereby discredit them all

[BDanielMayfield]

A lot of theories still need to be formally discredited.

• I hereby discredit them all

I wholeheartedly endorse this discredation. (My brain also concurs.)

[JohnD]

BDanielMayfield throws discredits about with gay abandon. Perhaps s/he would like to be more specific about where the discredits should fall, lest they fall back on her/im?

[BDanielMayfield]

BDanielMayfield throws discredits about with gay abandon. Perhaps s/he would like to be more specific about where the discredits should fall, lest they fall back on her/im?

Oh, I’m just being my somewhat contrarian and yet friendly self, a gentleman who dares to question everything, yet respectfully so. My core belief is logic, with a dash of good humor to keep things interesting.

I recommend being skeptical, especially of hard core skeptics. Keep your mind open, but not so open as to fall victim to the irrational.

Bruce

[Chris Peterson]

BDanielMayfield throws discredits about with gay abandon. Perhaps s/he would like to be more specific about where the discredits should fall, lest they fall back on her/im?

Oh, I’m just being my somewhat contrarian and yet friendly self, a gentleman who dares to question everything, yet respectfully so. My core belief is logic, with a dash of good humor to keep things interesting.
I recommend being skeptical, especially of hard core skeptics. Keep your mind open, but not so open as to fall victim to the irrational.

Bruce

Skepticism is a requirement of critical thinking. But skepticism is not the same as doubt. And questioning everything does not mean placing equal value on every idea.

It is skepticism that allows us to have a high degree of confidence in the substantial accuracy of most of today's core scientific theories.

[BDanielMayfield]

BDanielMayfield throws discredits about with gay abandon. Perhaps s/he would like to be more specific about where the discredits should fall, lest they fall back on her/im?

Oh, I’m just being my somewhat contrarian and yet friendly self, a gentleman who dares to question everything, yet respectfully so. My core belief is logic, with a dash of good humor to keep things interesting.
I recommend being skeptical, especially of hard core skeptics. Keep your mind open, but not so open as to fall victim to the irrational.

Bruce

Skepticism is a requirement of critical thinking. But skepticism is not the same as doubt. And questioning everything does not mean placing equal value on every idea.

I agree, and I certainly don’t place any value on irrational ideas. Down with flatearthism!

It is skepticism that allows us to have a high degree of confidence in the substantial accuracy of most of today's core scientific theories.

I cannot agree with that. The core of today’s scientific theories, at least as accepted by the established order, includes a ban on even considering intelligent design as a possible explanation for existence. If we were created, then the fundamental belief of modern science is based on a falsehood.

To JohnD (and any others) for more specifics I’m happy to answer PMs.

Bruce

[Chris Peterson]

Oh, I’m just being my somewhat contrarian and yet friendly self, a gentleman who dares to question everything, yet respectfully so. My core belief is logic, with a dash of good humor to keep things interesting.
I recommend being skeptical, especially of hard core skeptics. Keep your mind open, but not so open as to fall victim to the irrational.

Bruce

Skepticism is a requirement of critical thinking. But skepticism is not the same as doubt. And questioning everything does not mean placing equal value on every idea.

I agree, and I certainly don’t place any value on irrational ideas. Down with flatearthism!

It is skepticism that allows us to have a high degree of confidence in the substantial accuracy of most of today's core scientific theories.

I cannot agree with that. The core of today’s scientific theories, at least as accepted by the established order, includes a ban on even considering intelligent design as a possible explanation for existence. If we were created, then the fundamental belief of modern science is based on a falsehood.

To JohnD (and any others) for more specifics I’m happy to answer PMs.

Bruce

No theories "include a ban" on anything.

Intelligent design is massively discredited and has zero supportive evidence. But anybody is free to investigate it. No existing theories of evolution stand in the way of such investigation. It would be accepted if evidence could be provided.

[neufer]

It is skepticism that allows us to have a high degree of confidence in the substantial accuracy of most of today's core scientific theories.

I cannot agree with that. The core of today’s scientific theories, at least as accepted by the established order, includes a ban on even considering intelligent design as a possible explanation for existence. If we were created, then the fundamental belief of modern science is based on a falsehood.

No theories "include a ban" on anything.

Intelligent design is massively discredited and has zero supportive evidence. But anybody is free to investigate it. No existing theories of evolution stand in the way of such investigation. It would be accepted if evidence could be provided.

<<The U.S. National Academy of Sciences has stated that "creationism, intelligent design, and other claims of supernatural intervention in the origin of life or of species are not science because they are not testable by the methods of science." The U.S. National Science Teachers Association and the American Association for the Advancement of Science have termed it pseudoscience.

For a theory to qualify as scientific, it is expected to be:

• Consistent
  
  Parsimonious (sparing in its proposed entities or explanations, see Occam's Razor)
  
  Useful (describes and explains observed phenomena, and can be used predictively)
  
  Empirically testable and falsifiable
  
  Based on multiple observations, often in the form of controlled, repeated experiments
  
  Correctable and dynamic (modified in the light of observations that do not support it)
  
  Progressive (refines previous theories)
  
  Provisional or tentative (is open to experimental checking, and does not assert certainty)

For any theory, hypothesis or conjecture to be considered scientific, it must meet most, and ideally all, of these criteria. The fewer criteria are met, the less scientific it is; and if it meets only a few or none at all, then it cannot be treated as scientific in any meaningful sense of the word.

Typical objections to defining intelligent design as science are that it lacks consistency, violates the principle of parsimony, is not scientifically useful, is not falsifiable, is not empirically testable, and is not correctable, dynamic, provisional or progressive.

Critics also say that the intelligent design doctrine does not meet the Daubert Standard, the criteria for scientific evidence mandated by the US Supreme Court. The Daubert Standard governs which evidence can be considered scientific in United States federal courts and most state courts. Its four criteria are:

• The theoretical underpinnings of the methods must yield testable predictions by means of which the theory could be falsified.
  
  The methods should preferably be published in a peer-reviewed journal.
  
  There should be a known rate of error that can be used in evaluating the results.
  
  The methods should be generally accepted within the relevant scientific community.>>

[JohnD]

Oh, I’m just being my somewhat contrarian and yet friendly self, a gentleman who dares to question everything, yet respectfully so. My core belief is logic, with a dash of good humor to keep things interesting.
I recommend being skeptical, especially of hard core skeptics. Keep your mind open, but not so open as to fall victim to the irrational.

Bruce

Skepticism is a requirement of critical thinking. But skepticism is not the same as doubt. And questioning everything does not mean placing equal value on every idea.

I agree, and I certainly don’t place any value on irrational ideas. Down with flatearthism!

It is skepticism that allows us to have a high degree of confidence in the substantial accuracy of most of today's core scientific theories.

I cannot agree with that. The core of today’s scientific theories, at least as accepted by the established order, includes a ban on even considering intelligent design as a possible explanation for existence. If we were created, then the fundamental belief of modern science is based on a falsehood.

To JohnD (and any others) for more specifics I’m happy to answer PMs.

Bruce

There is no possibility of debate when one side is governed by faith.
And there will be no argueing with someone who is too afraid of public debate to offer to continue via PMs.
John

[owlice]

Outside of very limited exceptions, which are not met here, discussion of creationism/intelligent design is not permitted on Asterisk. Bruce was wrong to bring it up, but correct to try to move subsequent discussion to PMs. So if anyone wants to discuss it, take it to PMs, please.

Thanks.