Re: Venus's atmosphere

[Larry Woolf <larry.woolf@GAT.COM>]

Another interesting aspect of Venus's atmosphere:

From:
<http://hyperphysics.phy-astr.gsu.edu/hbase/solar/venusenv.html>

"The mass of the Venus atmosphere is about 90 times that of the Earth's
atmosphere. 90% of the Earth's atmosphere is within 10 km of the surface,
whereas you have to go to 50 km to capture 90% of the atmosphere of Venus."

From:
<http://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html>
"Venus Atmosphere
Surface pressure: 92 bars
Surface density: ~65. kg/m3
Scale height: 15.9 km
Total mass of atmosphere:  ~4.8 x 1020 kg"

From: <http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html>
By comparison, for earth:
"Terrestrial Atmosphere
Surface pressure: 1014 mb
Surface density: 1.217 kg/m3
Scale height: 8.5 km
Total mass of atmosphere:  5.1 x 1018 kg"

Larry Woolf
General Atomics
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> -----Original Message-----
> From: Frank Cardulla
> Sent: Wednesday, July 23, 2003 8:07 AM
> Subject: Venus's atmosphere
>
> Why is it that Venus has been able to retain an atmosphere that exerts a
> pressure about 90x that of the atmosphere on Earth?  The mass of
> Venus is less
> than that of Earth, so its gravitational acceleration is only 8.9
> m/s2.  Its
> atmosphere is hotter (about 737K vs. 288K).  Even though its
> atmosphere is mostly
> CO2, with a molar mass of 44 compared to an average of about 29
> for Earth's
> atmosphere, it seems counterintuitive that it could retain such a dense
> atmosphere compared to Earth.