Edit: It can almost certainly be excluded that the white spot was caused by Curiosity's ChemCam's laser, because it doesn't make sense that the laser was used at that time without taking images with ChemCam.
The only images captured by ChemCam on sol 550 were taken at least 1 hour before and at least 3 hours after the white stuff appeared on the surface of Mars, so it's highly unlikely that when that happened the laser was used.

the hole without the white stuff.[1]

The image above was captured by the Mars Hand Lens Imager (MAHLI) on sol 550 (february 22, 2014).

4 minutes later, white stuff seems to have emerged from one of the holes on that image, shown in the image below.

the same hole with the white stuff.[2]

The pictures above are part of a sequence of raw images shown on the mars.nasa.gov site. 6 images captured in 30 sec. show this white stuff, after that another feature was imaged.

What could this be ?

  • 7
    $\begingroup$ To me it looks like either a fault with the photograph or glare. I don't see the white patch emerging from the hole but on the surface of the rock to one side of the hole. $\endgroup$
    – Fred
    Oct 13, 2019 at 17:47
  • 1
    $\begingroup$ To me it looks a very much like vapor that has come out of the hole, hit a colder environment and transitioned from vapor to solid phase as ice. Having grown up in a place with plenty of sub-zero (0°F) mornings and seen my breath and other moist vapors turn to ice on windows and other surfaces, it certainly looks familiar to me. But that doesn't mean necessarily that that is what has actually happened here. $\endgroup$
    – uhoh
    Oct 13, 2019 at 19:32
  • 1
    $\begingroup$ @uhoh Reading your description i do remember also frozen flowers on a window and even frost on the blanket ! Having read the answer below i think its not vapor from the hole but maybe ice in the soil vaporized by the laser ? $\endgroup$
    – Cornelis
    Oct 14, 2019 at 7:58
  • 1
    $\begingroup$ @Conelisinspace I just don't know. If I had some reason to think it was not correct I would have commented, and I think others would do so as well. $\endgroup$
    – uhoh
    Oct 14, 2019 at 12:48
  • 1
    $\begingroup$ @Conelisinspace I can not understand the video at all, and I don't have anything else to contribute to this topic at this time. $\endgroup$
    – uhoh
    Oct 14, 2019 at 15:36

1 Answer 1


That's almost certainly ChemCam's laser vaporizing some rock for its spectrometer. You can see similar white spots in this video:

The laser fires in short pulses 10 times a second, and there's gaps between the video frames captured by MAHLI. The two are not synchronized and only sometimes align, allowing MAHLI to see the laser. Other times, MAHLI only captures the time between pulses and things like dust being kicked around.

It's clearly not a physical material on the rock, as this image taken at 08:09:22 UTC shows the spot:


While this one taken a few minutes later at 08:14:17 UTC does not:


The descriptions at those links refer to a multi-image focus merge process which will increase the odds of the laser spot being caught if the laser is on.

  • $\begingroup$ The white spots are similar, but 5 more images are captured within half a minute that show the same spot, while the spot from the vaporizing rock disappears again, doesn't it ? $\endgroup$
    – Cornelis
    Oct 13, 2019 at 21:04
  • $\begingroup$ I'm not sure why you're discounting the possibility that they're continuing to use ChemCam's laser while taking those images. $\endgroup$ Oct 14, 2019 at 22:05
  • $\begingroup$ The firing was 10 times a sec. for 10 sec. $\endgroup$
    – Cornelis
    Oct 14, 2019 at 22:23
  • $\begingroup$ In that specific video, yes. So? $\endgroup$ Oct 15, 2019 at 1:37
  • $\begingroup$ The times you mention in your answer are those when the merging was done with 2 to 8 images. You have to mention the times of each single image. Those single images are also shown farther on in the sequence of that sol. $\endgroup$
    – Cornelis
    Oct 15, 2019 at 8:30

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