B New Plume on Mars - ESA Image Revealed

[fizzy]

Hi, I found an alleged ESA image showing massive "plume" on Mars.

https://cdni.rt.com/files/2018.10/article/5bcf090cdda4c897418b45aa.jpg

While there have been several reports of plumes in recent years but this is in plain view and looks like a major event but I don't seem to find anything else on this and have not found a direct link to ESA for this image.

 

[Borg]

Could you reference the article where you found it?

 

[Bandersnatch]

Mars Expresses VMC Webcam has a photostream here:
https://www.flickr.com/photos/esa_marswebcam/
One of the photos of the current one:
https://www.flickr.com/photos/esa_marswebcam/31622920618/
Last month's:
https://www.flickr.com/photos/esa_marswebcam/44927778131/
This one is from Mars Orbiter from 2015
www.planetary.org/multimedia/space-images/mars/arsia-mons-and-cloud-mars.html
And this one is from VMC again, from 2009:
https://www.flickr.com/photos/esa_marswebcam/8267206000/

MARCI weather report shows condensation, but the plume is barely visible:
http://www.msss.com/msss_images/2018/10/17/

I'm posting all the other ones, in case somebody tries to jump on the 'It's a volcano!' craze that's just exploded in some social media.
I'm using 'plume' after OP, but let's say it together: it's a cloud.

 

[fizzy]

Thanks Bandersnatch.

I did put 'plume' in quotes because I thought it was improbable that it was volcanic as some are claiming.

What is evidence for calling this "cloud" ? Cloud of what substance?

If you look at the image I linked, it has a length which is a significant portion of the visible face of the planet. The 2015 event you linked seems to originate at almost exactly the same point ( and is a very similar direction ). Can that be explained as Arsia Mons elevating the air , if so why here and nowhere else. It would seem a little difficult to explain cloud formation which remains that concentrated without spreading whilst traveling such immense distances.

Just from a visual analysis it looks consistent with this being a surface emission of some kind.

 

[Bandersnatch]

My guess would be that it's an orographic cloud or a similar formation. That it's only over the southernmost peak could have something to do with insolation or weather patterns. The MARCI weather report site describes condensation over Arsia Mons as typical and identifies it as water, e.g.:

Condensate water ice clouds endured above Arsia Mons (southernmost volcano of the Tharsis Montes), signaling a return to seasonal martian norms after the recent planet-encircling dust event.

Let's remember that the Martian atmosphere is extremely sparse, and the planet is significantly smaller. We can't use our Earth-bound intuitions to judge what is too large a cloud to form.

 

[fizzy]

Thanks, it's interesting that the MRO images of the last two weeks seem to show cloud over Arsia Mons but none of the megametre long streaks running NW.

 

[Bandersnatch]

Thanks, it's interesting that the MRO images of the last two weeks seem to show cloud over Arsia Mons but none of the megametre long streaks running NW.

Yeah, I was wondering about that too. I think this might have to do with when the pictures were taken - the three Mars Express photos I've found* showing the trail invariably capture Arsia Mons near the dawn, while Mars Orbiter takes photos near the dusk terminator only. So it's morning vs afternoon.
It could be that there are some morning winds that blow the otherwise static cloud westward each day, or the angle of the sunlight simply highlights the trail better in the morning. The MRO site suggests that the condensation is an afternoon event, so the whole process could be a daily cycle.

I think the trails are due west, not NW, judging from the arrangement of Olympus and the Tharsis Montes.

*I haven't gone through the entire database, far from it.

 

[fizzy]

https://www.flickr.com/photos/esa_marswebcam/44927778131/
https://cdni.rt.com/files/2018.10/article/5bcf090cdda4c897418b45aa.jpg

The line of travel seems roughly parallel to the line from the most northerly volcano of the Tharsis Motes group to Olympus Mons. From the direction of rotation I estimated that to be NW ( on a eight point , eyeball compass ). I really can't see it as to the west.

The time of day argument is interesting. The shots I have seen show the ground shadow to the right of the cloud line. Unless I'm mistaken , that would mean it was illuminated from the west , ie end of day.

BTW is Olympus Mons really as symetrically placed as it appears to be w.r.t. the base line of Tharsis Motes ?

 

[Bandersnatch]

The line of travel seems roughly parallel to the line from the most northerly volcano of the Tharsis Motes group to Olympus Mons. From the direction of rotation I estimated that to be NW ( on a eight point , eyeball compass ). I really can't see it as to the west.

It looks that way to me:

 

[fizzy]

Thanks for the map. I'd estimate the O.M. - Ascreaus M. line is about 30 N of due west.

It's crazy the way these volcanoes move about depending upon the viewpoint/projection.

In the original view I posted, in the context of the full planet, they look almost like a perfect isosceles triangle. In the snip you took above, O.M. looks closer to the mid point of the two more northerly volcanoes ( yet it is the same image ); and on the map it look closer to a right-angled triangle. Do you know where I can find the ground distance between the three vertices?

Looking again at the original shot, you are correct it is drifting towards the dawn limb so it was taken before noon. Since martian tilt and solar day is very similar to Earth, I would guess about 9a.m. local time. While I agree with your caution about about applying Earth based experience to Mars; this may be due to diurnal heating which causes winds around dawn towards the night side plus easterly Coriolis trade winds. That would explain the apparently persistent direction of this phenomenon.

 

[Bandersnatch]

Do you know where I can find the ground distance between the three vertices?

Since it's a globe, any flat map projection is going to be distorted. I think best would be to take the Martian coordinates for each volcano from Wikipedia, and calculate the distance along the great circles from the haversine formula.
I was hoping Google Mars has this feature built in, just like with their map of Earth, but no luck.
I think, you should be able to use one of the many online calculators for great circle distance for Earth, and just scale the result proportionally to Mars' radius.

 

[moineau]

Could it be dust again?

 

[davenn]

Could it be dust again?

highly unlikely for a strong narrow plume like that and nothing anywhere else