Huygens Space Probe

[5614]

european space agency said "less than 300km/h" so i wouldnt estimate it to be as low as 200, infact i would estimate it to be 250km/h or more, but its a slight technicality, its still quite fast.

[noz92]

I heard them say about 200 on the TV show about it.

[Comandante]

does anyone know how long does it take to get all the data back from cassini (pictures from titan)... so far only 6 have been received

[5614]

i beg to differ, they have about 300 and a similar amount was lost when the 2nd transmission radio channel failed.

 

they also lost the doppler experiment, but they can estimate wind speeds from the descent rate/path and they estimate ~300mph winds, so does this -180 temp with 300mph winds sounds like a nice plannet?

[Dave]

Lovely place for a holiday. Its a shame that we only seemed to get 300 images instead of the 700 or so that they were expecting, but I suppose its better than nothing. They've issued an inquiry into how it managed to fail, and I suspect the cause will be human error. After all, we're not infallible

[noz92]

does anyone know how long does it take to get all the data back from cassini (pictures from titan)... so far only 6 have been received

 

About six to seven hours.

 

If radio telescopes can pick up the radio being released from Huygens, then why didn't we just use radio to see through the thick atmosphere?

[Dave]

It doesn't quite work like that. Radar and all that have a limited range because of the way waves propogate - also depends on the power of the transmitter etc.

[Martin]

does anybody know if there is a site that gives

surface conditions like temperature and atmospheric pressure?

 

atmospheric pressure was PREDICTED to be some 1.6 bar

that is 60 percent more than earth

but I want to know if Huygens actually measured it and what it was.

 

edit: from a pointer that 5614 gave I found this page

 

http://www.esa.int/SPECIALS/Cassini-Huygens/SEMMF2HHZTD_0.html

 

it says 94 kelvin and pressure = 1.5 bar.

I am still not sure how much of this is prediction and how much is measurement by the probe.

[Martin]

oh yeah.... and here:

http://www.esa.int/SPECIALS/Cassini-Huygens/

is the european space agency site

 

thanks, 5614,

 

at that site I found a "Titan facts" page dated 18 january (today) that

gives data like temp and pressure

http://www.esa.int/SPECIALS/Cassini-Huygens/SEMMF2HHZTD_0.html

 

surface temperature 94 Kelvin

and pressure 1.5 bar

I still do not know for sure if that is just prediction or reflects actual measurement, but at least it is recent

[Ophiolite]

The format of the site, the tone of the text, the absence of trumpeting of the landing all say to me this is prediction/deduction from distance observations. The data is going to trickle out. ESA don't have NASA's notion of PR.

[Martin]

.. The data is going to trickle out..

 

when it trickles about the atmospheric pressure at the surface please alert me, or the temperature! I would love to know

 

BTW the headline on yesterday's ESA article was that Huygens landed

on "mud"

that is great.

 

hydrocarbon slush plus minerals? a new idea of mud

 

here's the link again"

"Huygens lands in Titanian mud"

http://www.esa.int/SPECIALS/Cassini-Huygens/SEM5YW71Y3E_0.html

[ed84c]

In that dessent profile it shows the clouds being 26KM up! anybody know why they are so high, especially on such a small moon?

[Martin]

In that dessent profile it shows the clouds being 26KM up! anybody know why they are so high, especially on such a small moon?

 

that is an interesting question, one could ask a similar question about the earth

 

on the earth the upper limit of convection, and clouds, is about 10 km, right?

 

isnt it called the "tropopause"?

 

anybody want to offer some expert words on this?

 

when you fly some regular airline flight, it usually goes around 10 km high because then it is above the clouds and the turbulence that can be caused by convection.

 

above the "tropopause" there is no convection because the air temperature is approximately constant for many kilometers

 

for convection, there must be a sufficient GRADIENT of temperature.

the lower air has to be warmer and the temp has to drop off with altitude fast enough to trigger convection.

 

So the question is, WHAT DETERMINES THE HEIGHT OF THE TROPOPAUSE?

or anyway that would seem to be the question.

we can ask about the structure of any planet's atmosphere, or moon in this case.

 

================

maybe it is permissible to GUESS at this point. technical papers about the structure of titan atmosphere will be coming out and we can see if my guess is correct. I speculate that titan atmosphere is DENSER than our atmosphere for a longer ways out.

 

and this density is related to a greenhouse effect, which also extends farther out (on titan than at earth), and therefore

the kind of temperature gradient you need for convection extends farther out.

 

this is just speculative guesswork

 

I'm saying that on earth our strong gravity makes the atmosphere concentrate at low altitudes and the density falls off sharply with altitude (because our big gravity pulls the air down to the surface)

 

I'm saying that on titan with weak gravity the density falls off more gradually with altitude----and near surface it is 1.6 of earth so it is already some sixtypercent denser than earths at the surface, and if it falls off more slowly with height then it must be WAY denser than earth at say 10 km, or 30 km.

 

So the titan atmosphere structure is going to be spread out in altitude, compared with ours. It takes more altitude to reach their troposphere.

that's my speculation of why what u said about 30 km high clouds

[Comandante]

i'm curious; were there any high-res colour cameras onboard huygens, something like the one used to photograph mars?

[Ophiolite]

No, regretably. Remember the probe was launched seven years ago and builtwell before that, so the technology is certainly not current. The main restriction, however, was the data transfer rate that was possible. One hi-res colour photograhp and we could have kissed goodbye to most of the other data (and the other photos).

Think of this as comparable with the first pictures from the flyby of Mars in the 1960s. Low res, black and white pictures of cratered terrain, that suggested that Mars was rather like the moon.

[Gilded]

Got to say, I'd like to hike knee deep in hydrocarbon slush and perhaps a refreshing drink from a methane spring.

[Ophiolite]

You want to go to West Texas.

[snore2walk]

Titan' date=' getting a faint glimps of the planets surface, in which geologists believe to be similar to a young Earth.

[/quote']

but i thought Titan had a predominantly had an atmosphere that was predominantly methane and other organic gases. supposedly the surface is covered with organic slush, which is mostly frozen. NASA scientists, supposedly also wanted to refrain from sending probes into the planets atmosphere as they fear of contamination by terrestrial, bacteria that can survive the loing and arduous journey through harsh space. they fear that the sensor readings would then be flawed, as primal life forms, if any, then cannot be found, as the readings would obviously tainted. little, if any oxygen has been found in the atmosphere of Titan. was young Earth like this?.....

and yeah, Earth is still considered young, as young is a relative word.....lol....jus kiddin.....

[Ophiolite]

The comparison between Titan and the primeval Earth relate to the atmosphereic composition and almost nothing else. Titan's atmosphere is predominantly nitrogen with subsidiary organic gases such as methane.

I'm not sure if you were asking a rhetorical question, but the early Earth had no significant amounts of oxygen (<<1%). Substantial free oxygen was not present in our atmosphere till more than two billion years after the planet's formation.