Little Pluto

(G=EMC^2 Glazier) wrote


Well that would make 4 solid planets,and 4 gas planets. Well the 4
closest to the sun are rocky,and small.(why) The 4 outer planets are
made of gas and are the outer planets (why) Do birds of a
feather stick to gather?


http://www.solstation.com/stars/jovians.htm


Can we say gas planets just did not have
enough gas to become stars? Did Alpha Centuri come out of the same
nebular as our sun? If we found a rock or gas planet a LY from the sun
that had a diameter of 10 thousand miles would we add that planet,or is
it to far out? Bert





--
CeeBee


Google CeeBee @ www.geocities.com/ceebee_2

I like Gibor Basri's definition:

"A planet is a spherical non-fusor born in orbit around a fusor."

It has the advantage of being a definition based on
naturally-occurring benchmarks, such as orbit and sufficient mass to
achieve relative sphericity.

Any satellite of a planet would, by that definition, be just that,
despite its size. Anything too small to achieve sphericity would be
some form of planetesimal. It's simple. It's easy.

However, its chief disadvantage is that it dramatically increases the
number of planets in the Solar System to include the larger asteroids
and KBOs.

But I'd prefer that to the Pluto controversy.

kdn

On Wed, 16 Jul 2003 09:37:37 -0400 (EDT),
(G=EMC^2 Glazier) wrote:

Heard that the Rose planetarium demoted Pluto from a planet status

snip

Pluto's status as a planet has recently been disparaged in numerous
news articles, but nobody will successfully reclassify Pluto from a
planet. Once a planet, always a planet. However, it certainly can't
be denied that many astronomers feel that a reclassification is
appropriate. As far as I can tell, there are three reasons:

(1) The other outer planets of the Solar System are gas giants. They
have a small, solid core with thick atmospheres of methane, nitrogen
and other gases. In contrast, Pluto is a rocky planet with a thin
atmosphere (of similar gases).

(2) Pluto is very small. It's diameter of 2,274 km is only 65% of
earth's moon and 47% of Mercury, the next smallest planet. A few
decades ago, Pluto was considered to be much larger. Scientists kept
recomputing the size and mass to make it smaller and smaller.
Luckily, it didn't disappear altogether. In 1978, after the discovery
of Charon (Pluto's moon) the planet's size and mass was computed more
accurately.

(3) Pluto has an eccentric, egg-shaped orbit of 248 earth years which
occasionally brings it closer to the sun than Neptune.

Are there any other reasons some scientists believe that a
reclassification should be made? I wonder whether any other objects
in the Kuiper Belt or the Asteroid Belt will be discovered which have
both an atmosphere and a satellite.

--
Mike Bandy

"Mike Bandy" wrote...
in message ...

On Wed, 16 Jul 2003 09:37:37 -0400 (EDT),
(G=EMC^2 Glazier) wrote:

Heard that the Rose planetarium demoted Pluto from a planet status

snip

Pluto's status as a planet has recently been disparaged in numerous
news articles, but nobody will successfully reclassify Pluto from a
planet. Once a planet, always a planet. However, it certainly can't
be denied that many astronomers feel that a reclassification is
appropriate. As far as I can tell, there are three reasons:

(1) The other outer planets of the Solar System are gas giants. They
have a small, solid core with thick atmospheres of methane, nitrogen
and other gases. In contrast, Pluto is a rocky planet with a thin
atmosphere (of similar gases).

(2) Pluto is very small. It's diameter of 2,274 km is only 65% of
earth's moon and 47% of Mercury, the next smallest planet. A few
decades ago, Pluto was considered to be much larger. Scientists kept
recomputing the size and mass to make it smaller and smaller.
Luckily, it didn't disappear altogether. In 1978, after the discovery
of Charon (Pluto's moon) the planet's size and mass was computed more
accurately.

(3) Pluto has an eccentric, egg-shaped orbit of 248 earth years which
occasionally brings it closer to the sun than Neptune.

Are there any other reasons some scientists believe that a
reclassification should be made? I wonder whether any other objects
in the Kuiper Belt or the Asteroid Belt will be discovered which have
both an atmosphere and a satellite.

--
Mike Bandy

'Lo Mike --

The main reason that some scientists want Pluto reclassified is to
make collection and analysis of Kuiper Belt Objects data more
consistent and easy to deal with. Our emotional desire to keep
Pluto as a planet notwithstanding, the object is a comet wannabe,
nothing more. Our study of KBOs will be greatly simplified when
the IAU comes around to a more modern classification of stellar
system objects.

happy days and...
starry starry nights!

--
A smidgeon of fear and a sprinkle of strife
And a whole lotta love till your cold...
Most everyone here wants to live a long life,
Ah! but nobody wants to get old.

Paine Ellsworth

Hi Painius and Scott Nice informative posts. Astronomers have Pluto
being made like a comet(dirty snow ball.) Could it have a faint tail,if
viewed close up. The tail would be always facing away from the sun (I
think?). We found a ring around Jupiter just recently. I would think
that Saturn"s great ring of rocks and ice came from a very large comet.
Mostly ice because they reflect light so very well. Bert

David Knisely wrote:

NO, Pluto is *not* a comet wannabe. It is *much* larger than any known
comet (large enough to force its mass into a spherical shape, which is a
prime factor in one classification scheme for a planet). It is in a
stable orbit which does not have the extreme eccentricity which most
cometary orbits do. It is probably a Kuiper Belt object, but it is also
classed as a planet.

How far from the sun do comets begin to develop 'tails'? If this
distance is only a few AU then Pluto, whose perihelion is at about 30
AU, would never get warm enough, or encounter strong enough solar
winds, to create a coma even if it's made of the right materials.

--Odysseus

"Odysseus" wrote...
in message ...

David Knisely wrote:

NO, Pluto is *not* a comet wannabe. It is *much* larger than any known
comet (large enough to force its mass into a spherical shape, which is a
prime factor in one classification scheme for a planet). It is in a
stable orbit which does not have the extreme eccentricity which most
cometary orbits do. It is probably a Kuiper Belt object, but it is also
classed as a planet.

How far from the sun do comets begin to develop 'tails'? If this
distance is only a few AU then Pluto, whose perihelion is at about 30
AU, would never get warm enough, or encounter strong enough solar
winds, to create a coma even if it's made of the right materials.

--Odysseus

Comets must approach the Sun to about the distance of Mars' orbital
path (~1.5 AU) before the Sun's heat is enough for sublimation to
begin and a coma and tail to form. Actually, comets usually have two
or more tails. The main tail is a dust tail formed mostly by radiation
pressure. A second and third tail, ion tails, may form caused by the
solar wind.

http://amazing-space.stsci.edu/resou.../tails_nf.html

http://www.windows.ucar.edu/tour/lin....html&edu=high

happy days and...
starry starry nights!

--
So watch as we go 'round in circles,
Ending back where we began,
And there's only one outcome
For anyone's time--
Each of us getting a tan.

Paine Ellsworth

g

happy days and...
starry starry nights!

--
So watch as we go 'round in circles,
Ending back where we began,
And there's only one outcome
For anyone's time--
Each of us getting a tan.

Paine Ellsworth

"David Knisely" wrote in message ...
Panius posted:

ur emotional desire to keep
Pluto as a planet notwithstanding, the object is a comet wannabe,
nothing more. Our study of KBOs will be greatly simplified when
the IAU comes around to a more modern classification of stellar
system objects.

NO, Pluto is *not* a comet wannabe. It is *much* larger than any known
comet (large enough to force its mass into a spherical shape, which is a
prime factor in one classification scheme for a planet). It is in a
stable orbit which does not have the extreme eccentricity which most
cometary orbits do. It is probably a Kuiper Belt object, but it is also
classed as a planet.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

You posted:

Comets must approach the Sun to about the distance of Mars' orbital
path (~1.5 AU) before the Sun's heat is enough for sublimation to
begin and a coma and tail to form.

Actually, the comae begin to form at almost twice this distance (inside
of 2.8 A.U.). See INTRODUCTION TO PLANETARY GEOLOGY by Billy Glass.
Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

In article , David Knisely wrote:
You posted:

Comets must approach the Sun to about the distance of Mars' orbital
path (~1.5 AU) before the Sun's heat is enough for sublimation to
begin and a coma and tail to form.

Actually, the comae begin to form at almost twice this distance (inside
of 2.8 A.U.). See INTRODUCTION TO PLANETARY GEOLOGY by Billy Glass.
Clear skies to you.

Although this depends on the amount of volatiles in the comet. For instance,
Hale-Bopp was clearly active (i.e., had a coma and tail) when it was
discovered at ~7 AU, and pre-discovery images showed it had a coma at 13 AU.
This is believed due to volatiles (e.g., CO) trapped in the ice.