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AR15.COM
7/19/2015 11:51:06 AM EDT
I was just now reading a random page about new Pluto discoveries.  The probe indicated Pluto is outgassing nitrogen from it's atmosphere, and what they believe to be about 500 tons an hour.

If that estimate is correct,  how long could a small planet's atmosphere have been sustaining that?  At that rate, wouldn't it have long ago exhausted itself, considering it's a zillion years old?

*I'm actually not trying to create a "young world" argument; it's just that the math is curious to me.

7/19/2015 12:51:20 PM EDT
[#1]
Are you assuming no source of replenishment?

ETA: I don't think your question permits an answer, since we don't know the source of the atmosphere, so we don't know if it is being replaced.
7/19/2015 12:55:36 PM EDT
[#2]
87 parsecs.
7/19/2015 1:05:21 PM EDT
[#3]
1.3x1022kg losing 500,000kg/hr = 26x1015 hours or a little under 3 trillion years before the whole planet evaporates.
7/19/2015 1:06:51 PM EDT
[#4]
It's only about 6000 yrs old
7/19/2015 1:20:58 PM EDT
[#5]
Quote History
Quoted:
It's only about 6000 yrs old
View Quote


Stop it!

They all went back into the woodwork after the other two threads, and let's try to leave them there, while we have a discussion.

7/19/2015 1:47:45 PM EDT
[#6]
It's also worth considering that Pluto may only eject nitrogen in significant quantities (or at all) when it's close to the sun (relative to it's average distance).  Pluto's orbit is significantly more elliptical than that of any planet in the solar system, and is currently much closer to the sun than it's average distance.  If it only ejects significant quantities of nitrogen for the closest/warmest portion of it's orbit, then that would significantly extend the amount of time that it could continue to do so.
7/19/2015 1:51:11 PM EDT
[#7]
All we are seeing is what Pluto has left after 4 billion years of outgassing.
7/19/2015 1:58:54 PM EDT
[#8]
Mass 1.3*10**22 Kg = 2.9*10**18 tons
Rate                           5.0*10**2 tons/hr
                                5.7*10**15 hr
or 1.56 Billion years give or take a factor of 10.
7/19/2015 2:05:18 PM EDT
[#9]
Quote History
Quoted:
Mass 1.3*10**22 Kg = 2.9*10**18 tons
Rate                           5.0*10**2 tons/hr
                                5.7*10**15 hr
or 1.56 Billion years give or take a factor of 10.
View Quote


That would of course only hold if Pluto's mass were entirely nitrogen.


7/20/2015 7:53:47 PM EDT
[#10]
Quote History
Quoted:


That would of course only hold if Pluto's mass were entirely nitrogen.


View Quote View All Quotes
View All Quotes
Quote History
Quoted:
Quoted:
Mass 1.3*10**22 Kg = 2.9*10**18 tons
Rate                           5.0*10**2 tons/hr
                                5.7*10**15 hr
or 1.56 Billion years give or take a factor of 10.


That would of course only hold if Pluto's mass were entirely nitrogen.




Those figures were done using planetary mass?

Anyone want to take a crack at it, using an estimated atmospheric mass and percent nitrogen?
7/20/2015 8:24:43 PM EDT
[#11]
Quote History
Quoted:


Those figures were done using planetary mass?

Anyone want to take a crack at it, using an estimated atmospheric mass and percent nitrogen?
View Quote View All Quotes
View All Quotes
Quote History
Quoted:
Quoted:
Quoted:
Mass 1.3*10**22 Kg = 2.9*10**18 tons
Rate                           5.0*10**2 tons/hr
                                5.7*10**15 hr
or 1.56 Billion years give or take a factor of 10.


That would of course only hold if Pluto's mass were entirely nitrogen.




Those figures were done using planetary mass?

Anyone want to take a crack at it, using an estimated atmospheric mass and percent nitrogen?



Yeah, 1.3 x 10^22 kg is Pluto's planetary mass.  Haven't seen a detailed mass break down of it's atmosphere.

That' s probably something that will be an outcome of the New Horizons mission.

In any case, it's a pretty sure bet that Pluto is being replenished with nitrogen somehow.