IPB

Welcome Guest ( Log In | Register )

17 Pages V  « < 14 15 16 17 >  
Reply to this topicStart new topic
MSL - SAM and CHEMIN, Discussion of the science/results from these instruments
serpens
post Jun 11 2018, 03:44 AM
Post #226


Senior Member
****

Group: Members
Posts: 1043
Joined: 17-February 09
Member No.: 4605



QUOTE (Dalhousie @ Jun 10 2018, 11:02 PM) *
After this length of time and the many purgings I'd be sceptical of this assertion. The efforts to write off evidence of Mars methane by some seem to become ever more desperate attempts of straw clutching.

The fore-optics chamber is not purged. Small concentrations of methane have been measured in the Martian atmosphere and since that atmosphere is itself what we would classify on Earth as an industrial level vacuum the actual amount of methane is minute - but it is there. The seasonal variation in ppb must also take account of the cyclical variation in atmospheric pressure as CO2 transfers between summer/winter poles and this in itself means that the source of the methane spikes is not necessarily local. The real question is what causes the atypical spikes and at present no-one really knows. But I have seen no attempts to write off evidence of methane.
Go to the top of the page
 
+Quote Post
Dalhousie
post Jun 11 2018, 04:36 AM
Post #227


Newbie
*

Group: Members
Posts: 6
Joined: 19-February 16
Member No.: 7903



QUOTE (serpens @ Jun 11 2018, 04:44 AM) *
The fore-optics chamber is not purged. Small concentrations of methane have been measured in the Martian atmosphere and since that atmosphere is itself what we would classify on Earth as an industrial level vacuum the actual amount of methane is minute - but it is there. The seasonal variation in ppb must also take account of the cyclical variation in atmospheric pressure as CO2 transfers between summer/winter poles and this in itself means that the source of the methane spikes is not necessarily local. The real question is what causes the atypical spikes and at present no-one really knows. But I have seen no attempts to write off evidence of methane.



Kevin Zahnle has been an outspoken critic of methane on Mars on several occasions.
Go to the top of the page
 
+Quote Post
marsophile
post Jun 11 2018, 05:34 AM
Post #228


Member
***

Group: Members
Posts: 507
Joined: 10-September 08
Member No.: 4338



Methane signals due to contamination, if present, should show a gradually diminishing trend over time.

What are the prospects for Curiosity obtaining isotopic signatures of methane detections given enough time? Perhaps Florida air might have a unique and recognizable signature that could be distinguished even with rough measurements.
Go to the top of the page
 
+Quote Post
serpens
post Jun 11 2018, 08:51 AM
Post #229


Senior Member
****

Group: Members
Posts: 1043
Joined: 17-February 09
Member No.: 4605



Not really an outspoken critic surely. Kevin Zahnle agreed that the methane signature exists. He simply suggested that the spike could have come from the rover. At the time in particular that had to be a consideration.
Go to the top of the page
 
+Quote Post
MrNatural
post Jun 11 2018, 12:45 PM
Post #230


Junior Member
**

Group: Members
Posts: 42
Joined: 19-October 12
Member No.: 6719



Could the methane be off-gasing from plastics on MSL? Or breakdown products of plastics exposed to UV and temperature swings?
Go to the top of the page
 
+Quote Post
mcaplinger
post Jun 11 2018, 03:11 PM
Post #231


Senior Member
****

Group: Members
Posts: 2504
Joined: 13-September 05
Member No.: 497



QUOTE (MrNatural @ Jun 11 2018, 04:45 AM) *
Could the methane be off-gasing from plastics on MSL? Or breakdown products of plastics exposed to UV and temperature swings?

Read the paper, it's online. http://science.sciencemag.org/content/360/6393/1093.full

QUOTE
We argue against the possibility that the rover itself is a source of methane because we cannot identify any source large enough to produce even an instantaneous cloud of ~7 ppbv methane in a 10-m-diameter sphere around the rover...



--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post
Dalhousie
post Jun 12 2018, 12:37 AM
Post #232


Newbie
*

Group: Members
Posts: 6
Joined: 19-February 16
Member No.: 7903



QUOTE (serpens @ Jun 11 2018, 08:51 AM) *
Not really an outspoken critic surely. Kevin Zahnle agreed that the methane signature exists. He simply suggested that the spike could have come from the rover. At the time in particular that had to be a consideration.


Ge has reacted negatively to every major methane report since 2004. So he has got previous....
Go to the top of the page
 
+Quote Post
marsophile
post Jan 2 2019, 01:02 AM
Post #233


Member
***

Group: Members
Posts: 507
Joined: 10-September 08
Member No.: 4338



https://www.digitaltrends.com/cool-tech/mars-methane-tgo/

Does anyone who attended the referenced AGU session (https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/350159) know anything about this? The linked abstract does not mention it. Although perhaps not inconsistent, it seems to contrast sharply with the Curiosity findings.

[EDIT 01/5/19: A more detailed report here:
https://earthsky.org/space/esa-exomars-trac...missing-methane
which includes a link to a Science news item:
https://www.sciencemag.org/news/2018/12/mar...iously-vanished
]
Go to the top of the page
 
+Quote Post
marsophile
post Apr 5 2019, 07:28 PM
Post #234


Member
***

Group: Members
Posts: 507
Joined: 10-September 08
Member No.: 4338



http://spaceref.com/mars/mysterious-martia...-confirmed.html

This answers some questions. The methane spike detected by MSL seems to have been confirmed, and its source determined to be east of Gale Crater.
Go to the top of the page
 
+Quote Post
marsophile
post Jun 22 2019, 09:05 PM
Post #235


Member
***

Group: Members
Posts: 507
Joined: 10-September 08
Member No.: 4338



https://www.engadget.com/2019/06/22/curiosi...ts-methane-gas/

Another methane spike, said to be 3 times larger than the previous largest.

First reported in the New York Times (limited access).
Go to the top of the page
 
+Quote Post
Explorer1
post Jun 22 2019, 09:50 PM
Post #236


Senior Member
****

Group: Members
Posts: 2073
Joined: 13-February 10
From: Ontario
Member No.: 5221



Combined with the negative TGO results, definitely a complex picture emerging. Will there be a press release soon?
Go to the top of the page
 
+Quote Post
marsophile
post Jun 24 2019, 12:08 AM
Post #237


Member
***

Group: Members
Posts: 507
Joined: 10-September 08
Member No.: 4338



It was reported that some additional tests would be done over the weekend, and some results might be received tomorrow. There is this at nasa.gov:

https://www.nasa.gov/feature/jpl/curiosity-...-methane-levels

Maybe the quantity of methane involved is enough to do carbon isotope analysis? That might help to discriminate between possible sources.

If this is confirmed by other assets, but not by TGO, I will start to wonder if the TGO methane detector is non-functional. The simplest explanation for a complete non-detection might be a broken detector.
Go to the top of the page
 
+Quote Post
Gerald
post Jun 24 2019, 01:22 AM
Post #238


Senior Member
****

Group: Members
Posts: 2346
Joined: 7-December 12
Member No.: 6780



The TGO instruments, NOMAD and ACS, are spectrometers, and shouldn't be specific to some given trace gas. They detected other species very accurately.

The methane release detected by MSL might be very local.
Go to the top of the page
 
+Quote Post
serpens
post Jun 24 2019, 02:43 AM
Post #239


Senior Member
****

Group: Members
Posts: 1043
Joined: 17-February 09
Member No.: 4605



Using solar occultation which I believe covers sampling for trace gases including CH4 in a vertical atmospheric column, the sampling rate is around a kilometre per second from the surface up to 200 km altitude. So the fotprint of TGO is limited and TGO's orbit may or may not pass over the area of the methane pulse before it dissipates.

Go to the top of the page
 
+Quote Post
Explorer1
post Jun 24 2019, 03:26 AM
Post #240


Senior Member
****

Group: Members
Posts: 2073
Joined: 13-February 10
From: Ontario
Member No.: 5221



Press release is out; not much more details for now: https://www.jpl.nasa.gov/news/news.php?feature=7433

QUOTE
The SAM team organized a different experiment for this weekend to gather more information on what might be a transient plume. Whatever they find - even if it's an absence of methane - will add context to the recent measurement.

Curiosity's scientists need time to analyze these clues and conduct many more methane observations. They also need time to collaborate with other science teams, including those with the European Space Agency's Trace Gas Orbiter, which has been in its science orbit for a little over a year without detecting any methane. Combining observations from the surface and from orbit could help scientists locate sources of the gas on the planet and understand how long it lasts in the Martian atmosphere. That might explain why the Trace Gas Orbiter's and Curiosity's methane observations have been so different.
Go to the top of the page
 
+Quote Post

17 Pages V  « < 14 15 16 17 >
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 27th March 2024 - 05:21 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.