Posted on 11/24/2018 6:35:38 AM PST by ETL
Phobos’ grooves, which are visible across most of the moon’s surface, were first glimpsed in the 1970s by NASA’s Mariner and Viking missions.
Over the years, there has been no shortage of explanations put forward for how they formed.
Some planetary researchers have posited that large impacts on Mars have showered the nearby moon with groove-carving debris. Others think that Mars’ gravity is slowly tearing Phobos apart, and the grooves are signs of structural failure.
Still other scientists have made the case that there’s a connection between the grooves and the impact that created a large crater called Stickney.
In the 1970s, University of Lancaster’s Professor Lionel Wilson and Brown University’ Professor Jim Head proposed the idea that ejecta — bouncing, sliding and rolling boulders — from Stickney may have carved the grooves.
For a moon the size of the diminutive Phobos (17 miles, or 27 km, across), Stickney is a huge crater at 5.6 miles (9 km) across.
“The impact that formed it would have blown free tons of giant rocks, making the rolling boulder idea entirely plausible,” said Ken Ramsley, a researcher in the Department of Earth, Environmental and Planetary Sciences and the School of Engineering at Brown University.
“But there are also some problems with the idea. For example, not all of the grooves are aligned radially from Stickney as one might intuitively expect if Stickney ejecta did the carving And some grooves are superposed on top of each other, which suggests some must have already been there when superposed ones were created.”
“How could there be grooves created at two different times from one single event?”
(Excerpt) Read more at sci-news.com ...
Maybe the grooves were not formed while Phobos was/is a moon.
Perhaps this was a rolling rock on the surface of Mars. Grooves formed from the rolling. A nearby very large impact spewed debris, including Phobos, off the planet. Phobos entered a stable orbit.
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Lol! I know exactly where that is! I grew up that neighborhood: Lower East Side, New York City. In fact, my grandfather used to play bocci there: Houston Street. He owned a barbershop on Clinton Street, just off Houston.
A right turning rock. Definitely a Freeper for sure!
Comets are balls of ice and rocks. They aren’t made of plasma and they don’t burn.
Wait my mistake. Left turning. A Dummie instead.
“The impact that formed it would have blown free tons of giant rocks, making the rolling boulder idea entirely plausible,
This does not compute
If Phobos is 27 KM in diameter...then its gravitational attraction would be too small to retain a rolling boulder on its surface.
Since " blown free tons of giant rocks" is related to rocks on the earth...with a gravitational attractive force causing acceleration of 32 ft per second.
Well.... there is this one boulder.
Thanks for these! That is the time frame when I lived there. Born 1957, moved Oct 1970. Looking carefully at the pics for my grandfather! Got any more?
I don’t get it. The gravity would be minimal. So with what force would the boulders have etched the scars?
When I was stationed in Sicily (mid-70s), we enjoyed watching the old Sicilian men playing bocce. They were dead serious about it...and GOOD at the game.
https://duckduckgo.com/?q=Italians+playing+bocce&t=ucbrowser&iax=images&ia=images
The Rolling Boulders had bigger hits than the Rolling Stones.
The Rolling Boulders. Sounds like a band from Bedrock, as in the Flintstones. They actually did have a 60s-era band on in one episode: The Beau Brummelstones, a play on the group, The Beau Brummels, who had the 60s hit "Laugh Laugh". They even had them performing that song.
Those would have to be some damned big boulders.
“How Stellar Objects get their Groove back”
(Sounds like a documentary from a while ago ;-)
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