Alright, in the 8th edition, I need a chapter that does just the data and facts of Solar System objects. As an ongoing job and duty of astronomers to constantly refresh revise and update the data of our Solar System. Just today I was informed that the speed of the Sun in the Galaxy was not 220km/second but rather 230km/second.
This is what I mean by constant revising. So that anyone can go to this Astronomy Data and pull up whatever is needed.
This is my best data::
Now that Utexas site delivers this table with my
own modifications in the third column. These precessions are in
arcseconds/year
and thanks to Richard Fitzpatrick 2009/07/28 for
having this website. Basically I am after the
**observed precession** for that is the most
important number.
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Mercury, 5.75 observed, 5.50 theor, +0.25 deviat
Venus, 2.04 observed, 10.75 theor, -8.71 deviat
Earth, 11.45 observed, 11.87 theor, -0.42 deviat
Mars, 16.28 observed, 17.60 theor, -1.32 deviat
Jupiter, 6.55 observed, 7.42 theor, -0.87 deviat
Saturn, 19.50 observed, 18.36 theor, +1.14 deviat
Uranus, 3.34 observed, 2.72 theor, +0.62 deviat
Neptune, 0.36 observed, 0.65 theor, -0.29
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Sun, average density 1.4 gm/cm^3 but core is 150 gm/cm^3 and where
core is equal to about 0.2 solar radii
MEAN DENSITIES
Mercury, 5.4 gm/cm^3, metal core is 42% of volume
Venus, 5.2 gm/cm^3, metallic core
Earth, 5.5 gm/cm^3, metal core 17% volume
Moon, 3.3 gm/cm^3, iron core
Mars, 3.9 gm/cm^3, iron sulfide core
---------
Jupiter, 1.3 gm/cm^3, rocky core that is 12-45 Earth
mass and 3 to 15% of Jupiter's total mass
Saturn, 0.7 gm/cm^3, (less dense than water), rocky
core 9 to 22 times Earth mass
Uranus, 1.2 gm/cm^3, rock core
Neptune, 1.6 gm/cm^3, rock core of iron, nickel, silicates
Pluto, 2.1 gm/cm^3, rock core
--------
Satellites of Jupiter:
Io, 3.5 gm/cm^3, iron core
Europa, 3.0 gm/cm^3, iron core
Ganymede, 1.9 gm/cm^3, Fe and FeS iron core
Callisto, 1.8 gm/cm^3, silicate core
_____
Saturn satellite
Titan, 1.8 gm/cm^3 silicate core
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--- quoting from
http://www.indiana.edu/~g302/planets.pdf.
---
Solar System Composition
Metals
Oxides
Mass
Diameter
Fe, Ni
SiO
2
,MgO,FeO
Name
(10
27
g)
(10
3
km)
%
(10
27
g)
%
(10
27
g)
Sun
1,990,000
0.1
0.2
Mercury
0.33
4.88
50
0.16
50
0.17
Venus
4.87
12.11
30
1.46
69
3.36
Earth
5.97
12.76
29
1.73
69
4.12
Mars
0.64
6.79
10
0.06
90
Asteroids 0.0002
15
3x10
-5
85
1.7x10
-4
Jupiter
1900
143.2
4
80
9
170
Saturn
570
120
7
40
14
80
Uranus
88
51.8
8
7
17
15
Neptune
103
49.5
6
6
14
14
--- end quoting from
http://www.indiana.edu/~g302/planets.pdf.
---
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So I went looking around for rotation periods and tilt, today.
--- from this website ---
http://cseligman.com/text/sky/rotationvsday.htm
Rotation period
Mercury 58.6 days
Venus -243.0 days
Earth 23 hours 56 minutes
Moon 27.3 days
Mars 24 hours 37 minutes
Jupiter 9 hours 55 minutes
Saturn 10 hours 32 minutes
Uranus -17 hours 14 minutes
Neptune 16 hours 6 minutes
Pluto -6 days 9 hours
Angle of tilt on axis:
Mercury 0 degrees
Venus -3 degrees
Jupiter 3 degrees
Uranus -82 degrees
Pluto -72 degrees
Earth 23.5 degrees
Mars 25 degrees
Saturn 27degrees
Neptune 30 degrees
--- From a different website, I needed to know the rotation period of
the Sun ---
from a source:
Sun rotation period is approx 25 days
Next, I needed the data on the satellites of the gas giants of their
rotation-period and tilt:
From Wikipedia data:
Rotation period
Ganymede synchronous with orbit 7.1 days, with tilt 0 degrees
Callisto synchronous with orbit 16.7 days, 0 degrees
Io synchronous 1.7 days, 0 degrees
Europa synchronous with orbit 3.5 days, 0 degrees
Titan synchronous 15.9 days, 0 degrees tilt
Moon synchronous 27.3 days
Finally, I was suspicious that comets would also have rotation periods
so
went looking and found this site:
http://www.ifa.hawaii.edu/~meech/rot.html
Apparently the nucleus of comets has a rotation period
and this website gives rotation periods of about 7.6 hours to
15.0 hours on a list of comets studied.
Can I draw any conclusions so far?
Probably too premature, but I do notice the rotation period of our Sun
closely
matches that of the Moon. I also notice that the tilt on axis of Earth
is closely matched by that of Mars, Saturn, Neptune. I remember a
theory that the Moon collided with Earth very early in the history of
Earth some 4 billion years ago and due to that collision, the theory
went on to proffer that the tilt of Earth was caused. So I seriously
doubt that Earth Moon collision when Mars is so much identical in tilt
to Earth.
I do notice a pattern starting to emerge in that the inner planets
rotation period is in days whereas the gas giants are in hours. This
would be like saying that the inner planets have stopping grow fast
with Dirac new radioactivities and are old astro bodies whereas the
gas giants are young astro bodies and are growing fast with new cosmic
rays and cosmic gamma ray bursts.
But I need to find out more data and to analyze much more on this.
What is hopeful is that rotation period can eventually be the best
guide in astronomy as to a "age of a astro body." So that if we have a
fastly rotating galaxy, then it is a young galaxy and if we have a
galaxy with not much rotation at all, then it is very old.
Even applied to clusters of galaxies.
One of the gravest weakness of modern astronomy is the lack of
measuring for age and perhaps this rotation period linked to age is
going to open up alot of new data.
AP