APOD: Mars: Shadow at Point Lake (2013 Feb 05)

[Chris Peterson]

APOD Robot wrote:
What if you saw your shadow on Mars

Six more weeks of winter! :evil:

I was thinking the same thing. Except a Martian year is twice as long, so maybe that should be twelve more weeks?

[MargaritaMc]

Click to play embedded YouTube video.

I would think that everyone has watched this video a zillion times - but as I am still excited and awed by the achievement of putting Curiosity on Mars, I decided to post it.

Margarita

[BMAONE23]

APOD Robot wrote:
What if you saw your shadow on Mars

Six more weeks of winter!

I was thinking the same thing. Except a Martian year is twice as long, so maybe that should be twelve more weeks?

I thought about that too.
But isn't the end of winter always 6 to 7 weeks after Feb 2?

[neufer]

[b][color=#0000FF]The Wheel of the Year is an annual cycle of seasonal festivals in contemporary Paganism. It consists primarily of eight festivals based around the solstices and equinoxes, known as the quarter days, and the midpoints between, known as the cross quarter days.[/color][/b]

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isn't the end of winter always 6 to 7 weeks after Feb 2?

<<In western countries in the Northern Hemisphere, the official first day of spring is almost seven weeks (46–48 days) after Groundhog Day, on March 20 or March 21. The custom could have been a folk embodiment of the confusion created by the collision of two calendrical systems. Some ancient traditions marked the change of season at cross-quarter days such as Imbolc when daylight first makes significant progress against the night. Other traditions held that spring did not begin until the length of daylight overtook night at the Vernal Equinox. So an arbiter, the groundhog/hedgehog, was incorporated as a yearly custom to settle the two traditions. Sometimes spring begins at Imbolc, and sometimes
winter lasts six more weeks until the equinox.>>

[MargaritaMc]

In the lower left, the 'front bumper' of the rover has "Curiosity" spelled out, but it appears to be cut and shifted in the middle. Am I correct in assuming this is a 'defect' caused by splicing together the pieces of the mosaic?

I wrote to Photojournal at JPL-NASA as I also was curious about this.
This is the conversation:

On 6 Feb 2013 16:58, "Guy W (1871)"wrote:
THis is a mosaic image, assembled from component images.  Some of the alignments in this process are better than others.  The features closest to the camera, such as the Curiosity label on the hardware, tend to be harder to align than more distant features.

 

From: B. Karen (388L)
Sent: Wednesday, February 06, 2013 8:52 AM
To: Guy W (1871)
Subject: FW: Is the photo not lined up correctly?

 

This is interesting, Guy. Could you respond to Mrs. McE?

Thank you,

Karen

 

From: margarita mc
Sent: Wednesday, February 06, 2013 7:41 AM
To: photojournal
Subject: Is the photo not lined up correctly?

 

http://photojournal.jpl.nasa.gov/catalog/PIA16563

The above photo was used as the Apod for February 5th 2013 and was discussed on the related Forum ( http://asterisk.apod.com/viewtopic.php?f=9&t=30666)

Someone noted that the name Curiosity on the rover doesn't line up correctly. I looked at the original at your site in high resolution and saw that it really does not align. However, the relevant shadows DO seem aligned.

I have attached the detail in question and would be really interested in your comments - which I would request permission to post at Asterisk.

Many thanks
Margarita

I was really impressed that they made the effort to reply and did so so quickly.

Margarita

PS. I sent a close up of the name " Curiosity' cropped from the high resolution image I downloaded, but I don't think I can post it here as the smallest that I could get it was still over 500 kb

[geckzilla]

Try uploading it to http://www.imgur.com, Marg.

[MargaritaMc]

Try uploading it to http://www.imgur.com, Marg.

I think that would be over- kill! The image is just a close- up of the 5th Feb Apod.
I did look at the imgur site, but the hassle of signing up put me off - I can never work out the graphics that you have to copy in order to prove that you're not a robot as I just can't see them properly.
Best
Margarita

[bystander]

Cut from PIA16563

[Chris Peterson]

In the lower left, the 'front bumper' of the rover has "Curiosity" spelled out, but it appears to be cut and shifted in the middle. Am I correct in assuming this is a 'defect' caused by splicing together the pieces of the mosaic?

The ideal camera would have a fixed, point source aperture. That is, no matter what direction it was aimed, the aperture that collected the light would sit in the same place. In practice, that is not the case. The camera sits on a pan/tilt mechanism at the end of an arm. In order to look around, the camera has to be moved. That creates parallax- objects in the foreground move with respect to objects in the background, which makes it impossible to perfectly align mosaic images using simple image processing methods. It is possible to get perfect mosaics by mapping the camera data to a physical model and then re-rendering it- something that is done in certain cases, but generally isn't worthwhile in most images (and even then, there's usually no reason to map pieces of the rover).

[MargaritaMc]

Chris Peterson wrote
That creates parallax- objects in the foreground move with respect to objects in the background, which makes it impossible to perfectly align mosaic images using simple image processing methods

Ah ha! So both this Apod and the one we had recently of the Moon rising have actually served as very useful teaching tools about parallax. It has helped me to grasp what is involved a bit more, anyway.

Margarita

PS Thank you, bystander for posting the image.

[Beyond]

IF you don't keep track of your feet... you'll be seeing stars, but not the ones in the sky

[MargaritaMc]

IF you don't keep track of your feet... you'll be seeing stars, but not the ones in the sky

Ah, but that is where it is so useful to be a wheelchair user...

[Beyond]

IF you don't keep track of your feet... you'll be seeing stars, but not the ones in the sky

Ah, but that is where it is so useful to be a wheelchair user...

You got me on that one Although... if you don't set your brake correctly on a grade, you still may be seeing stars... after a wild ride

[geckzilla]

Try uploading it to http://www.imgur.com, Marg.

I think that would be over- kill! The image is just a close- up of the 5th Feb Apod.
I did look at the imgur site, but the hassle of signing up put me off - I can never work out the graphics that you have to copy in order to prove that you're not a robot as I just can't see them properly.
Best
Margarita

You don't have to sign up. Next to the imgur logo is a cloud with an arrow on it. You can click that and paste the link in and it will host it for you and also create multiple images sizes to link.

[MargaritaMc]

You don't have to sign up. Next to the imgur logo is a cloud with an arrow on it. You can click that and paste the link in and it will host it for you and also create multiple images sizes to link.

I tried this but it wouldn't work. Problem is not with imgur - there is some kind of incompatibility between this tablet PC I use and "???" . It is a Google Nexus 7, running the latest version of Android.

But thanks for the idea.
Margarita

[neufer]

Click to play embedded YouTube video.

Curiosity rover completes 1st drill into Mars rock
USA TODAY, 11:41a.m. EST February 9, 2013

<<LOS ANGELES (AP) — To scientists' excitement, the Curiosity rover has completed its first drilling on Mars and is preparing to analyze a pinch of powdery rock. Images beamed back to Earth overnight showed a fresh drill hole next to a test hole the rover made earlier. The feat marked yet another milestone for Curiosity, which landed last summer to hunt for the chemical building blocks of life. While previous Mars rovers have chiseled away at rocks, it's the first time one drilled down to obtain a sample. The exercise was so complex that engineers spent several days commanding Curiosity to drill test holes. The next task is to transfer the powder to Curiosity's onboard laboratories to study the chemical makeup. After the drilling activities, Curiosity will spend nine months driving to a mountain.>>

[neufer]

That "thing" in the upper center of neufer's picture, greatly resembles the business end of a ballpeen hammer. At least to me.

[b][color=#0000FF]3-D anaglyph from the right and left Mastcam from Curiosity showing the metal-looking protuberance. Credit: NASA/JPL/Caltech/Malin Space Science Systems. Anaglyph by by 2di7 & titanio44 on Flickr.[/color][/b]

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[b][color=#0000FF]Antarctic rock image supplied by Ronald Sletten, MSL science team.[/color][/b]

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Scientist Explains the Weird Shiny Thing on Mars
by Nancy Atkinson on February 12, 2013

<<Images from the Curiosity rover showed what looked like a piece of shiny metal sticking out from a rock. Some of our readers suggested that it might be a handle or knob of some kind. It’s a knob, yes, says Ronald Sletten from the Mars Science Laboratory team, but a completely natural formation. Sletten, from the University of Washington, explained that, not surprisingly, it is actually a part of the rock that is different — harder and more resistant to erosion — than the rest of the rock it’s embedded in.

On Earth, as on Mars, “often you can see knobs or projections on surfaces eroded by the wind, particularly when a harder, less erodible rock is on top,” Sletten said, via an email to Universe Today from the Jet Propulsion Laboratory media relations office. “The rock on top of the projection is likely more resistant to wind erosion and protects the underlying rock from being eroded.”

As far as why it appears shiny, Sletten said, “The shiny surface suggests that this rock has a fine grain and is relatively hard. Hard, fine grained rocks can be polished by the wind to form very smooth surfaces. It also may be shiny because it is wind-blasted and therefore dust-free, Sletten said, “while the surfaces not directly being eroded by wind may have a fine layer of reddish dust or rock-weathering rind. The sandblasted surfaces may reveal the inherent rock color and texture.”

He added that the object is an interesting study in how wind and the natural elements cause erosion and other effects on various types of rocks. In looking at a zoomed-in close-up of the “knob” or protuberance from the rock, Sletten said, “This knob has a different type of rock on the end of the projection. This rock may vary in composition or the rock grain size may be smaller.”

Because of the winds on Mars, there is quite a bit of erosion of rock, visible in the image above, as well as in many images from all the Mars rovers and landers. These type of surfaces are called “ventifacted” — wind-eroded surfaces caused by many fine particles of dust or sand impacting the surface over time. Areas of rocks may appear sculpted, as softer parts erode more easily or they may reflect small scale wind patterns, Sletten said.

So, this weird shiny thing on Mars is nothing too out of the ordinary —
not a door handle, hood ornament or not even Richard Hoagland’s bicycle.>>

[bystander]

Scientist Explains the Weird Shiny Thing on Mars
Universe Today by Nancy Atkinson on February 12, 2013

Another Weird Shiny Thing on Mars
Universe Today | Nancy Atkinson | 2013 Feb 05

Mars Rock Takes Unusual Form
NASA | JPL-Caltech | MSL Curiosity | 2013 Feb 11

[JohnD]

Some good images of the item here: http://www.jpl.nasa.gov/images/msl/2013 ... ifacts.pdf

Surely Curiosity will go over for a closer look. or else, isn't this an ideal target for the Chemcam?

JOhn

[neufer]

Some good images of the item here: http://www.jpl.nasa.gov/images/msl/2013 ... ifacts.pdf

Surely Curiosity will go over for a closer look. or else, isn't this an ideal target for the Chemcam?

I'm betting that it's an iron meteorite that had splashed into the water and gotten stuck in the mud.