[ Oran/NASAChatHost - 2 - 09:59:43 ]
Hello and welcome to today's NASA Quest Space Scientists Online/Mars Millennium chat with Mike Mellon. Mike is now online and ready to answer your questions.

[ MikeMellon/MarsGlobalSurveyor - 4 - 10:00:19 ]
Hello Everyone.

[ MikeMellon/MarsGlobalSurveyor - 5 - 10:04:48 ]
RE: [mamta] sir, can you please tell me what seson it will be on mars in january. could you please also let me know the relation between the seasons of earth and mars
Mamta, The seasons on Mars vary like they do on Earth but Mars has a year that is a little less than twice as long as Earth's year, so the seasons are twice as long. Last January was summer in the southern hemisphere of Mars - winter in the northern hemisphere.

[ MikeMellon/MarsGlobalSurveyor - 9 - 10:26:12 ]
RE: [Michelle] Hello Mike! A question came through to MTO Q&A: What is the PH of Mars?
Michelle, We have not yet measured the pH of Mars. We do know that the soil environment on Mars is very oxidizing from the results of past lander experiments. We don't know what the oxidizing chemical is nor how it might effect the pH.

[ MikeMellon/MarsGlobalSurveyor - 14 - 10:35:28 ]
RE: [Michelle] This question came to Mars Q&A from Tom S., in case he is unable to join this chat, I submit his question: Looking at the MOC high resolution images of the martian surface, I'm am struck by the utter absence of erosional features created by rainfall. On earth, gullies, ruts, channels would be ubiquitious. It seems it hasn't rained on this planet for eons (if ever). If my observation is correct, how does it square with the interpretation of the dendritic networks in the southern highlands as runoff features? Secondly, I found the argument for the existance of ancient oceans in the northern plains to be quite persuasive; however, is it possible for the planet to have had large standing bodies of water without at least some rainfall somewhere?
The valley networks on Mars have initially given us the impression of rainfall carved features. There is still a lot of debate about their origins, so I'll give you my opinion. One thing that we see that the valley networks lack is the smallest channels that we see in Earth valley networks (which are water erosion features). Since Mars lacks the smallest channels, we think some other process than rainfall has caused them. They may be caused by melting the underside of a snow pack, by geothermal heat, or they may be caused by sapping of ground water. One explanation may not be appropriate to explain all the features we see. Overall, the surface of Mars we see today is very much effected by wind erosion (particularly on the small scale we observe from MOC images and from landed cameras). As for oceans, this is still very debated by scientists. There seems to be a disconnect in our thinking between the presence of exposed water, the climate needed to support it and the geology which records it. We have a lot of work ahead of us to reconcile these ambiguities.

[ MikeMellon/MarsGlobalSurveyor - 15 - 10:38:39 ]
RE: [Michelle] What is the average composition of the Martian Soil?
Actually I'd need to look that up to give you a specific answer, but I can say that chemically it looks much like a basalt or weathered basalt like we would find from an earth volcano in Hawaii. The Mars Global Surveyor Thermal Emission Spectrometer can measure mineralogy from orbit. They see a lot of basalt as well. But the scale is 3 kilometers.

[ MikeMellon/MarsGlobalSurveyor - 18 - 10:41:55 ]
RE: [Michelle] Sean would like to know: I read about the three options for the mission to mars in 2003, but since then I haven't been able to get the facts straight on the progress. All I know is that they eliminated one option. Which two are left, or have they already come to a conclusion?
Sean, The plans that NASA have for 2003 have been changing rapidly this spring as they try to regroup from the lost space craft last winter. I have not been able to keep up to date, and have been spending most of my time doing research and data analysis. Not an informative answer, but true.

[ MikeMellon/MarsGlobalSurveyor - 19 - 10:45:16 ]
RE: [Michelle] Akera wants to know if you think it is possible to create a machine, preferably a satilite of some sort, to reflect sun rays to the planet and create an amosphere on Mars. Or, if possible, mix elements together and create an artificial atmosphere.
Akera, We could create a satellite to reflect the suns rays and warm Mars. It would be very expensive thought. This would not add more atmosphere to Mars. To do that we would need to bring more material to Mars, such as icy asteroids and comments. While technically possible, it is a major engineering problem and very, very expensive.

[ MikeMellon/MarsGlobalSurveyor - 21 - 10:50:06 ]
RE: [Michelle] Eric asks: If we neglect emotional reasoning what advantages are there in sending humans instead of robots to Mars?
Eric, There are advantages to sending humans to Mars. Frequently we want to explore beyond the limits of a single lander or a little rover, like the pathfinder mission. We might want to turn a rock over or do some complex analysis or a rock (or simply chip a piece off). A human is a much more versatile "machine" for doing these complex mechanical task. More importantly a human can think about what is best for exploration and science investigation on the spot. Having done some geologic field work myself, I can say that there is no substitute for being in the field yourself.

[ MikeMellon/MarsGlobalSurveyor - 23 - 10:54:24 ]
RE: [Michelle] Eric asks: If we find life on Mars, assuming the inhospitality of the planet, could there be potential danger for mankind? Actual studies are basically oriented on search of life; doesnt it restrain other discoveries, like finding new materials?
Eric, there could be a danger if we humans were exposed to some odd life on Mars. NASA is aware of this is spends a lot of time and money to prepare for protection, quarantine, and sterilization of samples we plan to bring back. But if life exists on Mars, it is probably of such a simple type that it would be in more danger from us than we would be from it. Also, yes searching only for life on Mars does limit our search for other discoveries. NASA has been pushing for searching for life (which is a good scientific problem), but most scientists are still thinking about non-life problems, like geology, climate, and Mars' history.

[ Michelle - 24 - 10:54:36 ]
Thank you Mike (and Oran) for the time you have taken to do this chat. Unfortunately for me, I have to run to go teach a class, so I must leave now. I will be looking for the answers in the archive. Thank you so very much!

[ MikeMellon/MarsGlobalSurveyor - 25 - 10:59:00 ]
RE: [Michelle] The Thermal Emission Spectrometer on Mars Global Surveyor discovered an abundance of hematite in one particular location on Mars. I understand that this site was considered to be a prime future landing site. Is the hematite site still a possible future landing site?
Michelle, I believe that the hematite site is still a prime future landing site. I think with the delays we will consider more sites than before. The hematite site is of interest because the type of hematite we see on the surface suggests it has formed in water and was possibly buried for a period of time. Since the lander missions are currently driven by the "search for life" than that makes the hematite site a good location to search for past life.

[ Oran/NASAChatHost - 26 - 10:59:54 ]
RE: [Michelle] Thank you Mike (and Oran) for the time you have taken to do this chat. Unfortunately for me, I have to run to go teach a class, so I must leave now. I will be looking for the answers in the archive. Thank you so very much!
Michelle, we're glad you could join us today, and thank you and your students for your great questions!

[ MikeMellon/MarsGlobalSurveyor - 27 - 11:00:10 ]
Thank you for your questions. They were very good ones.

[ Oran/NASAChatHost - 28 - 11:01:17 ]
This concludes today's NASA Quest Space Scientists Online/Mars Millennium chat with Mike Mellon. Thank you to everyone for joining us today. Our special thanks to Mike Mellon for sharing his time and expertise with us online. THANK YOU, Mike!!