The Giant Spider of Mercury?

[neufer]

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[img3="The striking troughs of Pantheon FosSae (Mercury)
the feature that MESSENGER scientists first
called "The Spider" when they discovered it."]http://planetary.s3.amazonaws.com/asset ... s_f840.gif[/img3]

The Giant Spider of Mercury
By Bill Dunford, Planetary Society, 2014/01/27

Mercury will surprise you. At first glance, it's gray and cratered, almost indistinguishable from the desolate far side of Earth's Moon. But one of the Solar System's most reliable rules holds sway at Mercury, too: take a closer look and you'll find things you never expected.

For one thing, the First Planet is not really colorless. Sure, if you flew by and looked out a window that's mostly what you'd see. But if you pass light reflected from Mercury's surface through filters sensitive to different wavelengths, then combine the images, something more reveals itself.

It turns out that different kinds of rock on the surface reflect subtly different colors. It takes special camera "eyes" to distinguish these hues, and there is just such a set of such instruments on board the robotic MESSENGER spacecraft now in orbit around Mercury. All deep space missions face dangers of one kind or another, but MESSENGER is an especially intrepid craft. The heat from the nearby Sun is so intense that the orbiter carries a large shield to protect its components. In fact, the heat reflected from Mercury's surface alone, like a hot sidewalk on a summer day, could cause enough problems that MESSENGER follows a highly elliptical orbit. It regularly takes the spacecraft high above the planet so it can cool off and not spend too much time baking near the surface.

From its looping vantage point around Mercury, MESSENGER has mapped almost every square kilometer of the planet's surface during the past couple of years of orbital flight. The spacecraft has seen some pretty striking landscapes along the way. Take Caloris Basin. Named, appropriately enough, for the Latin word for 'heat', this giant impact crater can be seen as the orange, circular area in the color image above. The Mariner 10 probe discovered Caloris in 1974, but at the time the feature was half hidden in the darkness of the Mercurial night side.

[b][color=#0000FF][size=135]Rome's Pantheon by Apollodorus[/size][/color][/b]

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MESSENGER first flew by Mercury in 2008 before it settled into its final orbit, and one of the first things it saw was the Caloris Basin in its full glory. Including, right near the center, this strange land. Mercury explorers saw an enormous set of grooved valleys, probably extensional faults, radiating from a 41-kilometer-wide crater. They called it "The Spider." Later on, the International Astronomical Union officially dubbed the region Pantheon Fossae. "Fossae" means "trenches", and here those trenches resemble the inside of the dome in a Roman temple. For the same reason, the central crater was given the name Apollodorus, after the Pantheon's architect.

Since then, scientists have continued to debate exactly what caused the faulting that pulled apart the rocks of Caloris Basin into such a distinctive pattern. They have also argued whether Apollodorus crater is, in fact, a coincidence unrelated to the grooves, since it appears to have formed later and not exactly at the center of the bullseye.

"The Spider" is one of the most hauntingly beautiful spaces in all the Solar System's strange wilderness. And to think it's a place we never even knew existed until a few short years ago. I can't help but wonder what else the ongoing robotic reconnaissance has left to reveal.>>

[Ann]

I knew spiders could be quite fast, but who'd'a thunk they could be Mercurial?

Ann

[Chris Peterson]

Art, the FSM is going to thrash you with his noodly appendages for suggesting he's a spider.

[neufer]

[b][color=#0000FF]Al-fredo, you're my older brother, and I love you. But don't ever take sides with anyone against the family again.[/color][/b]

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Art, the FSM is going to thrash you with his
noodly appendages for suggesting he's a spider.

I humbly ask his forgiveness.

[Nitpicker]

Ramen.

[neufer]

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Ramen.

. You are: the Slime Mold Finder
[list]not the Flying Spaghetti Monster [/list]

[Nitpicker]

Ramen.

. You are: the Slime Mold Finder
[list]not the Flying Spaghetti Monster [/list]

It's exactly that kind of human behaviour that really turns me off organised religion. That and the belief in god(s).

Very un-Pastafarian, neufer!

[neufer]

Very un-Pastafarian, neufer!

Deep down I'm antipasto.

[Nitpicker]

Very un-Pastafarian, neufer!

Deep down I'm antipasto.

You make miso sad.

[Beyond]

Ahh, Art. There are two things about Art. 1) It's an acquired taste that seems to vary with everyone. 2) Most Art is very old. Some may be as old as dirt itself. The Art in museums will usually look clean and tidy, whilst the Art that is out in natural surroundings may have a more weathered wrinkled/cracked look about it. 3) Art is unpredictable. One can never tell who will appreciate the Art at hand. For one, it's a treasure. For another it's eh!, what a waste. Unless you're a twin, or the like, no two people will ever see the same Art the same way, so as you come across all the different aspects of Art, just take them, or leave them, as you see fit. It's really all that one can do, concerning the mysteriousness of Art.

[BDanielMayfield]

A very insightful comment Beyond. Some appreciate almost all Art, while others share Harry S. Truman's opinion;

If THAT'S ART, I'm a HOTTENTOT!

[Beyond]

Yeah, once in a while i step out of the cave and it's a good day. IF i don't trip

[geckzilla]

Ramen.

. You are: the Slime Mold Finder
[list]not the Flying Spaghetti Monster [/list]

Look again, Art. Behold, one of His many noodly forms.



Chocolate Tube Slime by pellaea, on Flickr

[Ann]

Ahh, Art. There are two things about Art. 1) It's an acquired taste that seems to vary with everyone. 2) Most Art is very old. Some may be as old as dirt itself. The Art in museums will usually look clean and tidy, whilst the Art that is out in natural surroundings may have a more weathered wrinkled/cracked look about it. 3) Art is unpredictable. One can never tell who will appreciate the Art at hand. For one, it's a treasure. For another it's eh!, what a waste. Unless you're a twin, or the like, no two people will ever see the same Art the same way, so as you come across all the different aspects of Art, just take them, or leave them, as you see fit. It's really all that one can do, concerning the mysteriousness of Art.

I now know everything there is to know about Art:

Thanks, Beyond!

Ann

[Beyond]

Ann, that may be just a bit too much.

[rstevenson]

As the young son of a friend said when shown a piece of modern sculpture, "What happened to it Dad?"

Rob

[BDanielMayfield]

[img3="The striking troughs of Pantheon FosSae (Mercury)
the feature that MESSENGER scientists first
called "The Spider" when they discovered it."]http://planetary.s3.amazonaws.com/asset ... s_f840.gif[/img3][/float]The Giant Spider of Mercury
By Bill Dunford, Planetary Society, 2014/01/27

Mercury will surprise you. At first glance, it's gray and cratered, almost indistinguishable from the desolate far side of Earth's Moon. But one of the Solar System's most reliable rules holds sway at Mercury, too: take a closer look and you'll find things you never expected.


From its looping vantage point around Mercury, MESSENGER has mapped almost every square kilometer of the planet's surface during the past couple of years of orbital flight. The spacecraft has seen some pretty striking landscapes along the way. Take Caloris Basin. Named, appropriately enough, for the Latin word for 'heat', this giant impact crater can be seen as the orange, circular area in the color image above. The Mariner 10 probe discovered Caloris in 1974, but at the time the feature was half hidden in the darkness of the Mercurial night side.

...

MESSENGER first flew by Mercury in 2008 before it settled into its final orbit, and one of the first things it saw was the Caloris Basin in its full glory. Including, right near the center, this strange land. Mercury explorers saw an enormous set of grooved valleys, probably extensional faults, radiating from a 41-kilometer-wide crater. They called it "The Spider." Later on, the International Astronomical Union officially dubbed the region Pantheon Fossae. "Fossae" means "trenches", and here those trenches resemble the inside of the dome in a Roman temple. For the same reason, the central crater was given the name Apollodorus, after the Pantheon's architect.

Since then, scientists have continued to debate exactly what caused the faulting that pulled apart the rocks of Caloris Basin into such a distinctive pattern. They have also argued whether Apollodorus crater is, in fact, a coincidence unrelated to the grooves, since it appears to have formed later and not exactly at the center of the bullseye.

"The Spider" is one of the most hauntingly beautiful spaces in all the Solar System's strange wilderness. And to think it's a place we never even knew existed until a few short years ago. I can't help but wonder what else the ongoing robotic reconnaissance has left to reveal.>>

That is a fascinating area Art. To me it seems readily apparent that the groove valleys predate all the impact craters, including the largest. All the craters look to be on top of the groove features, which don’t cut through or across any craters. This terrain looks like something has caused the surface to be stretched out, as if something has pushed up from below, or the land has shrunk, tearing itself as it cooled.

The outside rim of the largest crater also has a strangely rectangular look to it.

Bruce

[neufer]

That is a fascinating area Art. To me it seems readily apparent that the groove valleys predate all the impact craters, including the largest. All the craters look to be on top of the groove features, which don’t cut through or across any craters. This terrain looks like something has caused the surface to be stretched out, as if something has pushed up from below, or the land has shrunk, tearing itself as it cooled.

The outside rim of the largest crater also has a strangely rectangular look to it.

• Perhaps it's a volcano.

[BDanielMayfield]

There could be a volcanic cause without there being a surface volcano.

A subsurface igneous intrusion, like a laccolith, perhaps? Which may have pushed up and cracked the surface without filling the fractures? Then maybe the area settles over time, leaving the fractured terrain intact and at roughly the original elevation?

Consider a wider view of the whole Caloris Basin:

If you zoom in near the center of the blue circle you can see the Pantheon Fossae area.

And the Caloris Basin wiki article was very interesting:

The Caloris Basin, also called Caloris Planitia, is a large impact crater on Mercury about 1,550 km (960 mi) in diameter,[1] one of the largest impact basins in the solar system. "Calor" is Latin for "heat" and the basin is so-named because the Sun is almost directly overhead every second time Mercury passes perihelion. The crater, discovered in 1974, is surrounded by a ring of mountains approximately 2 km (1.2 mi) tall.

The Caloris Basin was discovered on images taken by the Mariner 10 probe in 1974. It was situated on the terminator—the line dividing the daytime and nighttime hemispheres—at the time the probe passed by, and so half of the crater could not be imaged. Later, on January 15, 2008, one of the first photos of the planet taken by the MESSENGER probe revealed the crater in its entirety.

The crater was initially estimated to be about 1,300 km (810 mi) in diameter, though this was increased to 1,550 km (960 mi) based on subsequent images taken by MESSENGER.[1] It is ringed by mountains up to 2 km (1.2 mi) high. Inside the crater walls, the floor of the crater is filled by lava plains, similar to the maria of the Moon. Outside the walls, material ejected in the impact which created the basin extends for 1,000 km (620 mi), and concentric rings surround the crater. In the center of the basin is a region containing numerous radial troughs that appear to be extensional faults, with a 40 km (25 mi) crater located near the center of the pattern. The exact cause of this pattern of troughs is not currently known.[1] The feature is named Pantheon Fossae.[2]

Formation[edit]
The impacting body is estimated to have been at least 100km (62 miles) in diameter.[3] Bodies in the inner solar system experienced a heavy bombardment of large rocky bodies in the first billion years or so of the solar system. The impact which created the Caloris Basin must have occurred after most of the heavy bombardment had finished, because fewer impact craters are seen on its floor than exist on comparably-sized regions outside the crater. Similar impact basins on the Moon such as the Mare Imbrium and Mare Orientale are believed to have formed at about the same time, possibly indicating that there was a 'spike' of large impacts towards the end of the heavy bombardment phase of the early solar system.[4] Based on MESSENGER's photographs, Caloris' age has been determined to be between 3.8 and 3.9 billion years.[1]

Antipodal chaotic terrain and global effects[edit]
The giant impact believed to have formed Caloris may have had global consequences for the planet. At the exact antipode of the basin is a large area of hilly, grooved terrain, with few small impact craters that are known as the Chaotic Terrain (also 'Weird Terrain'). It is thought by some to have been created as seismic waves from the impact converged on the opposite side of the planet.[5] Alternatively, it has been suggested that this terrain formed as a result of the convergence of ejecta at this basin’s antipode.[6] This hypothetical impact is also believed to have triggered volcanic activity on Mercury, resulting in the formation of smooth plains.[7] Surrounding Caloris Basin is a series of geologic formations thought to have been produced by the basin's ejecta, collectively called the Caloris Group.

[neufer]

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MESSENGER Finds Spacecraft Graveyard on Mercury
Release Date: April 1, 2014

<<The MESSENGER team today released images that appear to show the remains of several now-inoperative NASA spacecraft on Mercury's surface. The spacecraft remnants are clustered along the inner wall of a 400-m-diameter impact crater on Borealis Planitia, a large area of volcanic plains. The crater lies within an enigmatic region of Mercury that the MESSENGER team has informally dubbed “The Borealis Triangle.” Remarkably, one of the spacecraft has been tentatively identified as Mariner 10, which flew by Mercury three times in 1974–1975. Mariner 10 was presumed to be in a heliocentric orbit, although it may have been imaged by MESSENGER three years ago to the day. Stranger still, the Mars Global Surveyor (MGS) probe also seems to have been delivered to this spacecraft graveyard. MGS ceased operations at Mars in 2007, and a landing on Mercury was not part of its original mission design. Most unexpected of all is one of the twin Gravity Recovery and Interior Laboratory (GRAIL) spacecraft. The GRAIL mission ended in December 2012 when both craft were thought to have impacted the surface of the Moon, yet at least one of the spacecraft seems to have survived that impact and later repeated the feat on Mercury.

Although this remarkable finding was enabled by the increased resolution at which MESSENGER can now image the surface of Mercury as its periapsis altitude lessens with each orbit, the MESSENGER team is at a loss to explain this collection of inoperative spacecraft within the Borealis Triangle. MESSENGER Project Scientist Nat MacRulf believes preternatural forces are responsible. “Both Mariner 10 and Mars Global Surveyor flew magnetometer experiments. What if something went wrong? Could we then be looking at the effects of a magnetically induced wormhole, like that generated during the Philadelphia Experiment in the 1940s? I don’t see why not.” As to why the GRAIL spacecraft, which lacked a magnetometer, would also become caught in a magnetic wormhole, MacRulf simply scratched his head. “The darn thing’s made of metal, isn’t it?” Not everyone agrees with MacRulf’s assessment, however. MESSENGER Project Manager Ellen Summers favors a more prosaic explanation for how missions to other planets have ended up at Mercury. “Spacecraft are notoriously hard to direct, especially once they’re switched off. It took one flyby of Earth and two of Venus before we eventually managed to steer MESSENGER toward Mercury. A spacecraft at Mars might easily make its way to Mercury if left to its own devices.”

Keen, nonetheless, to take advantage of this strange new observation, the MESSENGER mission operations and navigation teams met this morning to discuss plans to transition the spacecraft from an orbiter to a lander. “The crater in which we’ve spotted these decommissioned spacecraft, which we’re proposing be named after Eloy d’Amerval, would make a great site to make in situ measurements of Mercury’s strange Borealis region,” says MESSENGER mission design lead Adam McJames. He added: “If other craft can crash-land there, I don’t see why we can’t!” before rushing off to assist in using MESSENGER’s own magnetometer to take readings of an unusual aurora-like phenomenon beginning to form above the Borealis Triangle. At press time, McJames, Summers, and MacRulf would not confirm reports of the appearance at Mercury of the Galileo spacecraft, last tracked plummeting deep into Jupiter’s magnetically charged atmosphere in 2003.>>

[geckzilla]

But they Photoshopped out the monolith and other alien evidence. You guys are lucky I don't have the energy to pull some silly April Fool's joke at the forum. I could force you to look at a brand new, awesome white text on black background template for a day with at least one lens flare present in the header.