Date: December 10, 1997
Featuring: Jim Murphy
Meteorologist, Mars Pathfinder
Ames Research Center, Pasadena, California
[ MrsDabbs1stgrade/WestView-murphychatter 09:55:05 ]
We 6th graders are here in Sioux Center, IA looking out at the snow that has slowly accumulated over a few days to about 3 in. total. We have read Jim Murphy's bio and are very pleased to have the opportunity to visit with him. Students will be coming and going as schedules come and go. That's OK. More students can participate that way.
[ Harris8thgrade/KPNorth-murphychatter 09:58:48 ]
Mrs. Dabbs first grade what is the weather like there? (CA?)
[ Bill/ForestParkES-murphychatter 10:00:03 ]
[ Donna/KaiserElementary-murphychatter10:00:35 ]
Hi, Mrs. Ewing here with two of my 4-6th grade students. More will join us in a few minutes. It is cold and windy for southern California! Hi everyone.
[ MrsDabbs1stgrade/WestView-murphychatter 10:01:39 ]
It is cold, but no snow..yet. We are in Washington. Where are you?
[ Harris8thgrade/KPNorth-murphychatter 10:03:22 ]
Mrs. Dabbs first grade what is the weather like there? (CA?)
[ Gagnersclass/MorrisMN-murphychatter 10:03:41 ]
It's cold here in Morris,MN.
[ MrsOsClass/Barre-murphychatter 10:03:54 ]
Hi, We're a Fourth Grade Class from Barre, Vermont.
[ MrsDabbs1stgrade/WestView-murphychatter 10:04:18 ]
Mr Murphy: Is the wind so stong that is makes sandstorms?
[ Harris8thgrade/KPNorth-murphychatter 10:05:02 ]
Mrs. Dabb, it is cool here in Mass. we are expecting snow. Hi Mr. Murphy!
[ Sandy/NASAChatHost10:05:07 ]
Hello Everyone! Jim Murphy is here and ready to go! Hope you have your questions ready :-)
[ JimMurphyAmes10:05:20 ]
Hello All, I am happy to be here with you today to chat about Mars, and Earth, and their similarities / differences...
[ Bill/ForestParkES-murphychatter 10:05:34 ]
no snow here in Nanaimo, Canada we're on the west coast and our flowers are still blooming! but this is unusual.
[ MrsOsClass/Barre-murphychatter10:06:03 ]
It's cold here in Vermont (about 24 degress F).
Welcome to Bill in Nanaimo, Canada! Sounds like El Nino is in effect up there too!
[ JimMurphyAmes 10:07:57 ]
RE: [Gagnersclass/MorrisMN-murphychatter] Is there precipitation on Mars?
Yes, there probably is precipitation on Mars, but is all in the frozen form (i.e. snow). The water in the martian atmosphere is either in the gas (water vapor) state or the frozen state (snow, ice on the ground). There is also likely carbon dioxide (CO2) snow, since CO2 is the main component of the atmosphere, and it freezes out in the winter polar regions. If it freezes out in the atmosphere, the frozen CO2 snow particles will flutter to the ground, just like the snow we are familiar with...
[ JimMurphyAmes 10:10:25 ]
RE: [MrsOsClass/Barre-murphychatter] Here's one of our questions for Jim. What's the difference in temperature between Mars and Earth?
In general, the temperatures on Mars are much colder then here on Earth. A warm day on Mars might have air temperatures near the ground get up to 40 degrees fahrenheit (but not very often or at too many places), while the coldest spots on Mars see temperatures as cold as -200 degrees Fahrenheit, which is colder than even the coldest temperature measured in Antarctica.
[ Gagnersclass/MorrisMN-murphychatter 10:11:51 ]
We have to go to lunch now, we'll be back in fifteen minutes.
[ Sandy/NASAChatHost 10:12:49
RE: [LabbaneWood/SoutheastElementary-murphychatter] Hello from Southeast Elementary in Jenks, OK! Sorry we're late...technical difficulties! We are fourth graders in Mrs. Labbane's and Mrs. Wood's class. We're excited about chatting with you!
Welcome LabbaneWood Southeast Elem.!!! I'm very happy to see that you worked through your technical difficulties!!!
[ MrsOsClass/Barre-murphychatter 10:12:54 ]
Jim, How fast has the wind ever blown on Mars?
[ JimMurphyAmes 10:26:09 ]
Mrs. Os: The wind on Mars has probably never blown faster than about 400 miles per hour. We can determine this because the wind can't blow fatser than the speed of sound, and the speed of sound on mars is 400-450 miles per hour; at the surface of mars, I would guess that the fastest wind is probably 150-200 miles per hour...but that ir really just a guess.
[ JimMurphyAmes10:12:57 ]
RE: [Marske/SiouxCenterMiddleSchool-murphychatter] Do you think we could ever live on Mars considering the weather there?
Yes, I think we could live on Mars even considering the temperatures there, but you would not catch me running around outside in shorts !! People who travel there will be required to live within contained environments (i.e. spacesgips), since there is no air to breathe. Just as people now spend the winter at the Earths South Pole (where it gets pretty darn cold), I think that we can deal with the cold Martian temperatures, especially if we were near the equator, where it probably does not get much colder than minus -120 degrees Fahrenheit or so...
[ LabbaneWood/SoutheastElementary-murphychatter 10:13:39 ]
Why isn't there an ozone layer on Mars?
[ JimMurphyAmes 10:27:49
Labbane/Wood: Good question. There is essentially no ozone layer on Mars, since there is hardly an oxygen (2) on Mars, and since to produce ozone (3) the oxygen must be 'broken' in half (procuding two O molecules) with each molecule being added to another oxygen molecule, that lack of oxygen leads to a lack of ozone.
[ JimMurphyAmes 10:15:00 ]
RE: [Harris8thgrade/KPNorth-murphychatter] Mr. Murphy we have been studying weather and have been impressed with the differences in temp. - what are the temperature ranges now on mars?
The maximum air temperatures near the surface are probably +40 Fahrenheit or so, while the coldest temperatures near the surface are probably -230 Fahrenheit or so.
[ MrsDabbs1stgrade/WestView-murphychatter 10:15:43 ]
Mr. Murphy: Are you worried about the weather harming the Pathfinder?
[ JimMurphyAmes 10:30:01 ]
Mrs. Dabbs: Well, I wish I were worried about the weather harming Pathfinder. We believe that Pathfinder is no longer working, probably because the cold temperatures caues some part of the inside of the spacecraft to break, since things tend to become more likely to break or crack when the get very cold (I always tend to think of plastic trash cans cracking in cold weather...)
[ LabbaneWood/SoutheastElementary-murphychatter10:15:56 ]
Can the technologies used on Pathfinder be used here on Earth?
Labbane / Wood: Yes, the technologies used on Pathfinder can be used here on Earth. The stereo camera capability is used to produce 3-D movies (horror movies from teh 50's are prime examples), the rover has shown that a remotely controlled vehicle can be driven around to do science, and in fact such a rover was used in the desert of Chile earlier this year.
[ JimMurphyAmes 10:16:36 ]
RE: [Donna/KaiserElementary-murphychatter] We know that it is much colder on Mars. This is because the sun is farther away. What other reasons are there, Mr. Murphy?
Good question! Mars is colder because it is farther from the sun, and additionally it is colder because there is less atmosphere on Mars, which produces a less intense 'green house' effect (that is, the blanketing effect provided by the atmosphere).
[ MrsDabbs1stgrade/WestView-murphychatter 10:18:03 ]
Mr. Murphy: Do parts of Mars have seasons like Earth?
[ JimMurphyAmes 10:33:25
Mrs. Dabbs: Yes, you are correct, all parts of Mars have season just like here on Earth. So, during the summer it is warmer than in the winter. But, since Mars does not have trees, there are no pretty colors in the autumn, nor blooming flowers in the spring :)
RE: [Gagnersclass/MorrisMN murphychatter] How does the pressure on Mars compare to Earth?
The surface pressure of the atmosphere on mars is about 7 millibars (a unit of measure of pressure), compared with the surface pressure here on the surface of the Earth of 1013 millibars (29.93 inches of mercury, in a secoond unit of measure)
[ JohnWaylandElementary-murphychatter 10:18:56 ]
How does the extreme conditions on Mars affect the instruments? Can you use the same instruments that we use on Earth to measure temperature, wind speeds, and pressure on Mars? Did you build special instruments so they would work on Mars?
[ JimMurphyAmes 10:38:03
John Wayland: We can use the same type of pressure measuring instruments on both Earth and Mars; using a liquid in glass thermometer would not be too great an idean on Mars, since the limited number and slow motion of the molecules would mean that it would take a while for the thermometer to respond; we use electrical temperature measuring devcices on Mars. For wind, something which moves due to the wind is less desirable than some electrical or temperature measuring device.
[ Marske/SiouxCenterMiddleSchool-murphychatter 10:19:41 ]
Do they have El Nino like phenomenon that might cause storm conditions like here on Earth?
[ JimMurphyAmes 10:39:49
Marske: Well, since Mars does not have oceans, and El Nino is really a change in ocean water temperatures and their effects upon the weather, mars won't have El Nino's like we doe here on Earth,....but, if the dust on the surface were to move around, and clear from some areas and appear in others, the effect on the surface temperatures might gewnerate weather variations which maybe we could call 'El Dustos'!
[ JimMurphyAmes10:20:11 ]
RE: [Marske/SiouxCenterMiddleSchool-murphychatter] We were wondering what kind of weather do you like to study?
In the case of Mars, I like to study the weather processes which lead to the development of global dust storm. During these storms, dust is lifted into the atmosphere and covers much of the planet...we don't have any similar type of weather event here on Earth. I'm also studying what might be dust devils on mars. Here on Earth, I am interested in hurricanes and tornadoes / dust devils
[ Harris8thgrade/KPNorth-murphychatter10:20:16 ]
How thick can the snow get? Does it pile up?
[ JimMurphyAmes 10:40:45
Harris: The 'snow' might pile up to several meters depth (1 meter ~ 3 feet) at the polar latitudes in the polar cap.
[ Bill/ForestParkES-murphychatter 10:20:19 ]
Why in the winter do the polar ice caps grow?
[ LabbaneWood/SoutheastElementary-murphychatter 10:21:13 ]
Is there a rating scale for the dust devils on Mars similar to the F scale for tornadoes?
[ JimMurphyAmes 10:42:12
Labanne / Wood: There is no official rating scale for dust storms on Mars, but we tend to refer to them (from small to big) as local, regional, hemispheric, planetary, and Great with the distinction between planetary and great and matter of opinion.
[ Harris8thgrade/KPNorth-murphychatter 10:22:00 ]
Samrout would like to ask how the dust stroms in Lebanon compare to Martian storms?
[ JimMurphyAmes 10:44:23
Harris/ Samrut: The dust storms in Lebanon compare with Mars storms in that both result from strong winds near the surface which bounce big sand particles around which, when the hit the ground. knoock small dust particles into the air. These dust particles are small enough for the wind to carry them up and away. However, the Lebanese storms tend to be smaller than the regional and larger storms on Mars.
[ JimMurphyAmes 10:22:38 ]
RE: [Bill/ForestParkES-murphychatter] why are there such big temperature changes in such a short time ?
I'm not quite sure about what large time changes of temperature you are talking about, but if they are day night differences, the change is due to the 'green house' type argument a few answers back. If there is less atmosphere above you, the ground can emit thermal radiation to space without much coming back from the atmosphere. This means the ground cools very efficiently, and so does the air in contact with it.
[ JohnWaylandElementary-murphychatter 10:23:13 ]
Another question we have? Can the weather information that we gather from Mars tell us anything about its past? Also, our earth has had periods of warming and cooling (ice ages) did Mars have any extreme weather changes from warming to cooling.
[ JimMurphyAmes 10:45:44
John Wayland: The weather today can't really tell us too much about weather in the past, but the various features on the planet's surface, such as apparent water channels, and layering in the polar ices, do suggest that Mars was warmer and wetter long, long (billions of years) ago.
[ JimMurphyAmes 10:24:31 ]
RE: [Harris8thgrade/KPNorth-murphychatter] How long is it light for at the martian poles?
Just like here on Earth, the sun shine at the martian poles for one-half of a martian year, from the neginning of spring through the end of summer. Mars is tilted 25 degrees, compared with Earth's 23.5 degree tilt (or is it 22.5?), and it is this tilt of the ratation axis which produces our, and Mars' seasons.
[ MrsOsClass/Barre-murphychatter 10:25:20 ]
Sorry, we need to leave now. Thanks for all the great information!
[ Marske/SiouxCenterMiddleSchool-murphychatter 10:25:58 ]
Did you have a role model when you decided to go into meteorolgy?
[ JimMurphyAmes 10:46:52
Marske: I don't recall a specific role model who interested me in meteorology. But I do remember talking with several of the TV meteorologists in New Orleans when I was in junior high and high school, and in general they were encouraging of my interest in weather.
[ LabbaneWood/SoutheastElementary-murphychatter 10:25:58 ]
Do you plan on being a team member for the next rover in 2001? If so, what changes would you make?
Labanne / Wood: I would love to be a member of one of the upcoming missions to mars. I I have the chance, the one thing I would change is to do more work testiung all our weather instruments before they go to ensure that they work properly.
[ Gagnersclass/MorrisMN-murphychatter 10:26:57 ]
Hello, we're back.
[ Bill/ForestParkES-murphychatter 10:28:46 ]
are there seasonal variations in temperature on mars?
[ LabbaneWood/SoutheastElementary-murphychatter 10:28:49 ]
In what season do most dust devils occur?
[ JimMurphyAmes 10:49:44
Labanne / Wood: Good question... Surprisingly dust devils have been observed during all seasons on Mars, at the three northern hemisphere sites at which we have had landers. Here on earth, they are primarily a summer time feature of the wetaher in hot, deserty regions.
[ Marske/SiouxCenterMiddleSchool-murphychatter 10:29:13 ]
What is the most extreme weather on both Earth and Mars?
Marske: On Earth, the hottest temperature ever recorded is 134 degrees Fahrenheit, in Libya, which the coldest is something like minus 134 Fahrenheit, at the South Pole. On Mars, the warmest we have ever measured is about 25 degrees fahrenheit, while the coldest is -190 Fahrenheit or so.
[ Gagnersclass/MorrisMN-murphychatter 10:29:34 ]
What are the average high and low temps on Mars ?
[ JimMurphyAmes 10:57:08
Gagners: The average high temperatures observed by Pathfinder, during northern summer, were +10 Fahrenheit, while the average minimum was -110 F or so.
[ MrsDabbs1stgrade/WestView-murphychatter 10:29:54 ]
Mr. Murphy: Are there clouds on Mars?
[ JohnWaylandElementary-murphychatter 10:32:17 ]
We live in a Valley and a lot of our weather is affected by the mountains and other geographic features. How do the geographic features of Mars play a role....Like Olympus Mons?
[ JimMurphyAmes 10:54:40
John Wayland: The Shenandoah Valley is beautiful..I envy you living there. The mountains and Valleys on Mars do effect the weather. The big volcanoes are often the site of cloud formation as air rides up their sides, cools as it does, and condenses, forming clouds. STorms ofetn generate down stream of mountain ranges here in eart, and the same apparently holds tru on mars.
[ Marske/SiouxCenterMiddleSchool-murphychatter 10:32:55
We were wondering about the life of a busy scientist. Do you feel like you have enough time with your family?
[ JimMurphyAmes 10:52:51
Marske: There are often times when I feel like I don't have enough time with my family, but in general I think it works out OK. My really beusy times at work tend to come in spurts, not all the time, so I try to spend as much time at home when things are'nt too hectic. I was away for an entire month for mars Pathfinder this past July, but then we took a family vacation in August. It was fun.
[ Sandy/NASAChatHost 10:33:47
EVERYONE: Jim is typing as quickly as he can, but we are about 20 questions behind. He wants to answer ALL of your questions. Hold up sending questions for 5 minutes.... Thanks :-)
[ Marske/SiouxCenterMiddleSchool-murphychatter 10:35:06
What inspired you to work on the Mars Pathfinder project?
[ JohnWaylandElementary-murphychatter 10:35:26 ]
Been there...done that...Marilyn
Is the atmosphere of Mars ever dust-free?
[ JimMurphyAmes 10:35:29
Labbane / Wood: The dust probably does not ever completely clear from the martian atmosphere. ALl three spacecraft we have placed on the surface have seen dust in the atmosphere all the time. There might be locations where most of the dust clears at some time, and it might become less deeply mixed into th eatmosphere at some seasons, but I think there is always some dust in the atmosphere.
[ LabbaneWood/SoutheastElementary-murphychatter 10:37:36
Thanks for your time, Mr. Murphy. We really enjoyed chatting with you and the other schools, and we learned a lot. Our time is up...best wishes from Southeast Elementary in Jenks, OK. :)
Thankyou Mr. Murphy for chatting with us! Thanks for everything!
[ Gagnersclass/MorrisMN-murphychatter 10:39:27 ]
[ JohnWaylandElementary-murphychatter 10:44:33 ]
On Earth we gather much of our weather information from satellites. NASA just sent up a new satellite (TRIMM) to measure rainfall. We know about MGS orbiting Mars. Can we use a system of weather satellites for Mars too?
[ JimMurphyAmes 10:56:02
John Wayland: Yes, we can use a system of weather satellites for mars. The satellites should carry cameras so that we can see clouds and dust storms, and the satellites should also carry instruments to 'see' infrared wavelengths, from which we can determine temperatures of the air and ground.
[ Marske/SiouxCenterMiddleSchool-murphychatter 10:45:22 ]
We were wondering what has been the most interesting information you've gotten from the Mars Pathfinder?
[ JimMurphyAmes 10:59:08
Marske: The most interesting weather info I think we have gotten from mars Pathfinder is how rapidly the air temperatures near the ground change over the time interval of a few minutes during the day. Tempearture changes as large as 30 degrees Fahrenheit occur within a few minutes, followed by a return to the original temperature. This indicates that hot air is rsing and cold air is sinking quite drmatically.
[ Gagnersclass/MorrisMN-murphychatter 10:48:24 ]
Has the weather changed since the Viking missions and if so, how?
[ JimMurphyAmes 11:01:05
Gagners: The weather does not appear to have changed too much since the Viking missions. Pathfinder landed about 1000 miles from Viking lander 1, and the temperatures, pressures, winds, and dust amount in the atmosphere seen by Pathfinder look quite a bit like what we saw at Viking Lander 1, 11 mars year earlier ( a Mars year is about 689 Earth days, or 669 mars days; a Mars day is 24 hours and 37 minutes long, so just slightly laonger than our day here on Earth...)
[ Marske/SiouxCenterMiddleSchool-murphychatter 10:50:26
Do you think your job is fun? And why?
[ JimMurphyAmes 11:02:50
Marske: My job is great fun !!! It was real thrill being involved in Pathfinder, and realizing that I was the first person seeing the weather data from mars from that mission. It is a great joy trying to learn new things, and answer questions which no one else has. Also, it is nice being able to choose the topics I want to study, at least a good part of the time.
What do you plan to do with the weather data from Mars?
Marske: The weather data we have collected we are presently studing to learn more about martian weather (dust devils, storm systems, heat transfer from the warm ground to thge atmosphere, and other such topics). Beginning next month, all the data will be made available to anyone who wnats it, so they (and you!) can study it as well...
[ Marske/SiouxCenterMiddleSchool-murphychatter 10:58:39
Not to be personal, but we were wondering what kind of a salary does a scientist like you make a year?
Marske: I am happy with what I make. I think the range of salaries probably starts at $25-30 thousand per year, and goes up to $70-100 thousand for tenured professors. I am definitely towards the low end of the scale, but for the work I am able to perform, and the freedom I feel, I don't have much complaint about my salary.
We would like to thank Mr. Murphy for spending quality time with us today. We learned a lot and appreciated chatting with you. Bye from Sioux Center.
[ Bill/ForestParkES-murphychatter 11:01:17 ]
If Mars has a very thin atmosphere why did the pathfinder get so hot when going through the thin martian atmosphere?
[ JimMurphyAmes 11:08:53
Bill in Canada: Good question. Even though Mars has a 'thin' (not meant to imply shallow), Pathfinder got so hot descending through the atmosphere in part because it was travelling so fast (15,000 miles per hour), and those molecules in the air 'drag' on the spacecraft and slow it down, and in tyhe process that friction generates heat (like a rope burn for those unfortunate enough to have experienced that).
[ Gagnersclass/MorrisMN-murphychatter 11:04:57 ]
Do you know why the satellites of Mars are not round like the Earth's moon?
[ JimMurphyAmes 11:12:33
Gagners: Really good question! I think the current idea is that our moon formed after a collision with Earth by large object which threw some material into orbit around Earth, and this material formed into a rotating mass which eventually forms a sphere. At mars, it is believed that Phobos and Deimos might be captured asteroids. And, since asteroids are thought to be possible remnants of bigger pieces which broke into small pieces when they collided out in space, they have jagged edges since they are pices broken off from a larger body (a bit like smooth glass breaking into jagged pieces...).
[ Sandy/NASAChatHost 11:12:36
EVERYONE: It's time for Jim to get back to work! Thanks to all of you for doing your homework before the chat and asking such detailed and thoughtful questions! You did a great job! And a special THANK YOU to JIM for taking the time to spend with us today. Your answers were very informative, and I for one, learned some new things.
HAPPY HOLIDAYS TO EVERYONE AND JOIN US AGAIN IN JANUARY FOR NEW CHATS :-)
[ JimMurphyAmes 11:13:31
Thanks for the terrific questions. This is a terrific way to spend my time (and just one more reason whiy I love my job). Ya'll take care out there, have fun studying about space, and have a happy holiday season. Jim Murphy.
[ Sandy/NASAChatHost 11:24:04
RE: [Bill/ForestParkES-murphychatter] Ta ta from forest park school Nanaimo British Columbia we've had a great time chatting so long for now.
GOODBYE Bill! So glad you could join us today ;-)