Since when is Juptier gaseous?

Does anyone know when Jupiter was discovered to be a gas giant rather
than a rocky planet?

This tidbit seems to elude my googling skills.

TIA!

--
head -n1 /etc/*-{version,release} && uname -moprs
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"Dario Niedermann" wrote in message
...
| Does anyone know when Jupiter was discovered to be a gas giant rather
| than a rocky planet?
|
| This tidbit seems to elude my googling skills.
|
| TIA!
|
Kepler lived December 27, 1571 - November 15, 1630

http://www.robinsonlibrary.com/scien...y/herschel.htm
Probably around 1780-1800, Kepler's laws were known for 150 years...
Through a combination of mass and size (Jupiter is a visible disc in even
low power telescopes) the density was computed to be low, which implies a
gas.

Dario Niedermann wrote:
Does anyone know when Jupiter was discovered to be a gas giant rather
than a rocky planet?

This tidbit seems to elude my googling skills.

TIA!


Even in the 17th C, with measurements of Jupiter's diameter (hence volume),
and Kepler's laws generalised to apply to any system such as Jupiter's
satellites (which required application of Newton's universal law of
gravity), the density of Jupiter could be calculated. However, the average
was somewhat more than the density of water, and at the time astronomers
might have postulated that Jupiter was mainly liquid with a thick
atmosphere.

I found one popular article from 1927 by no less than E. C. Slipher, who
described Jupiter as having a very deep gaseous atmosphere. But this is not
the same as saying it is a gas giant. However, from the low density,
Slipher could easily calculate that it could not be rocky. Perhaps liquid
was considered a possibility, but nothing explicit in the article said this
(an ASP Leaflet no 12, Sept 1927).

http://adsabs.harvard.edu/abs/1927ASPL....1...47S

A paper from 1924 by Harold Jeffries discusses what appear to be new results
derived by him from the ellipticity of the planets Jupiter and Saturn, and
he concludes that each must have extensive deep atmospheres: a rocky core,
a thick layer of ice, and an extensive deep atmosphere of mainly H and He,
with other gases.

He doesn't use the term gas giant, but he seems to be getting close to the
words with his model.

http://adsabs.harvard.edu/abs/1924MNRAS..84..534J

You need to remember that the term "gas giant" is based on the composition
(mainly H, He) and not the physical state of the entire planet. By
comparison Uranus and Neptune are often said to be "ice giants".

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

On 14/04/2011 02:48, Dario Niedermann wrote:
Does anyone know when Jupiter was discovered to be a gas giant rather
than a rocky planet?

This tidbit seems to elude my googling skills.


Google Books allows you to search through old books and journals (in
general if you select the "Full View" texts you'll get the older ones
free from copyright).

A search for "Jupiter" & "Gaseous" is a reasonable place to start.

Here's one from 1870

"The fuel of the sun" By William Mattieu Williams

pages 190 - 191 give a hypothesis of a predominantly gaseous planet.

Down the left hand side, the search tools allows you to select your date
range.

Have fun!

On Apr 13, 6:48*pm, Dario Niedermann wrote:
Does anyone know when Jupiter was discovered to be a gas giant rather
than a rocky planet?

This tidbit seems to elude my googling skills.

TIA!

-- head -n1 /etc/*-{version,release} && uname -moprs

Slackware 12.2.0
Linux 2.6.27.31-smp i686 AMD Turion(tm) 64 Mobile Technology MK-36 GNU/Linux

For all we know, Jupiter is a hollow sphere, perhaps containing mostly
hydrogen and helium, and if the shell is thick and dense enough then
the gravity inside is near zero.

Gravity inside a hollow sphere or shell = zero
http://hyperphysics.phy-astr.gsu.edu...ell2.html#wtls

http://translate.google.com/#
Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet”

Dario Niedermann wrote:

Does anyone know when Jupiter was discovered to be a gas giant rather
than a rocky planet?

Many thanks to all respondents.

I thought the discovery was much more recent, being under the impression
that in "2001 A Space Odyssey", the only surviving astronaut lands on
Jupiter. Turns out it was actually a "stargate" in Jupiter's proximity,
so no blatant mistake on the writers' part.

--
head -n1 /etc/*-{version,release} && uname -moprs
Slackware 12.2.0
Linux 2.6.27.31-smp i686 AMD Turion(tm) 64 Mobile Technology MK-36 GNU/Linux

On Apr 15, 6:37*am, Dario Niedermann wrote:
Dario Niedermann wrote:
Does anyone know when Jupiter was discovered to be a gas giant rather
than a rocky planet?

Many thanks to all respondents.

I thought the discovery was much more recent, being under the impression
that in "2001 A Space Odyssey", the only surviving astronaut lands on
Jupiter. Turns out it was actually a "stargate" in Jupiter's proximity,
so no blatant mistake on the writers' part.

-- head -n1 /etc/*-{version,release} && uname -moprs

Slackware 12.2.0
Linux 2.6.27.31-smp i686 AMD Turion(tm) 64 Mobile Technology MK-36 GNU/Linux

The highly paramagnetic crust of Jupiter could be 1000 km thick, and
inside merely hydrogen and helium.

For all we know, Jupiter is a hollow sphere, perhaps containing mostly
hydrogen and helium, and if the shell is thick and dense enough then
the gravity inside is near zero.

Gravity inside a hollow sphere or shell = zero
http://hyperphysics.phy-astr.gsu.edu...ell2.html#wtls

http://translate.google.com/#
Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet”

On 11-04-14 07:32 PM, Brad Guth wrote:
For all we know, Jupiter is a hollow sphere, perhaps containing mostly
hydrogen and helium, and if the shell is thick and dense enough then
the gravity inside is near zero.

We know considerably more than that. We've seen comets and asteroids
crashing into it for decades now, and they always look like they're
hitting a fluid.

Yousuf Khan

On Apr 18, 5:30*am, Yousuf Khan wrote:
On 11-04-14 07:32 PM, Brad Guth wrote:

For all we know, Jupiter is a hollow sphere, perhaps containing mostly
hydrogen and helium, and if the shell is thick and dense enough then
the gravity inside is near zero.

We know considerably more than that. We've seen comets and asteroids
crashing into it for decades now, and they always look like they're
hitting a fluid.

* * * * Yousuf Khan

The hollow sphere notion still has the same mass to offer, so it
should hold an atmosphere that's pretty darn thick and robust. (say
1000 km worth of atmosphere shouldn't be unexpected)

http://translate.google.com/#
Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet”

On Mon, 18 Apr 2011 20:06:44 -0700 (PDT), Brad Guth
wrote:

On Apr 18, 5:30*am, Yousuf Khan wrote:
On 11-04-14 07:32 PM, Brad Guth wrote:

For all we know, Jupiter is a hollow sphere, perhaps containing mostly
hydrogen and helium, and if the shell is thick and dense enough then
the gravity inside is near zero.

We know considerably more than that. We've seen comets and asteroids
crashing into it for decades now, and they always look like they're
hitting a fluid.

* * * * Yousuf Khan

The hollow sphere notion still has the same mass to offer, so it
should hold an atmosphere that's pretty darn thick and robust. (say
1000 km worth of atmosphere shouldn't be unexpected)

http://translate.google.com/#
Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet”

Unless you've made that hollow sphere from unobtainium it will
collapse into a solid sphere.

Bud