Is our Solar system weird?

[KrupS]

Now it is believed that:

It reviews the results of extra-solar planet finding, with over 200 planets so far discovered in a little under 200 star systems. The surprise finding is that nothing like our solar system has yet been discovered.

 

Our solar system is atypical. We have a system with small rocky planets close to the sun, and large gas giants further out. All are in almost circular orbits, moving in a well behaved, stately way, around the sun. And of course, we have Earth in the liquid water belt, also in a beautiful, stable, almost circular orbit.

 

Other stellar systems have all kinds of different systems. Giant planets orbiting very close to their parent star are common. Wildly eccentic and elliptical orbits. Planets massively bigger than Jupiter. Every indication of violent interactions between bodies within those systems.

 

At first glance it seems that all this is true. But consider the system Gliese 581. We write the order of the values of orbital radii: 0.030, 0.041, 0.073, 0.146, 0.220, 0.758. Multiply this numbers by 23.65. Obtain a series of numbers: 0,71, 0,97; 1.73, 3.45, 5.20, 17.9. What is it?

 

Comparable to the orbital radius of planets in the solar system:

0.71 ; 0.97 ; 1.73 ; 3.45 ; 5.20 ; --- ; 17.9

0.72 ; 1.00 ; 1.52 ; ---- ; 5.20 ; 9.54 ; 19.1

 

As you can see, there is an obvious similarity, which confirms that planetary systems are created for one scenario.

Although over five hundred planets discovered so far, but there are the only 7 systems are multyplanetary enough (more 3 planet) for reliable analysis. There are : , KeGliese 581, Gliese 876, 55Cancri, Upsilon Andromedae A system, My Arae, HD10180, Kepler-11. And all of them have made in accordance with an universal principle (but not Bode-Titius's "Law"). More over, systems of moons of Saturn, Jupiter, Uranus have made in this way.

Note the following important fact. When comparing the solar system with a system Gliese 581 major satelites of the systems have coincided to each other. This is our general principle.

Let's draw up a comparative table of the six systems (left to right): Gliese 581, Solar, Saturn, Uranus, Jupiter, Gliese 876. Orbital radius of the largest satelites take equal to 1. This celestial bodies are: Gliese 581 d, Jupiter, Titan, Titania, Ganymede, Gliese 876 e. Consider the part of systems lying below the orbits of primary satelite. Obtain the table:

 

 

In celestial mechanics, there is no quantization. However, the relative positions of the planets (or moons) are very strange. Positions of the planets for some reason is not accidental. Planets tend to cluster around certain numerical values of orbital radii.

 

Celestial bodies, which have similar numerical values of the relative orbital radii (with respect to the orbital radius of the primary planet) , located in the same row.

 

At first glance, the problem of "quantization" of the planetary orbits is easily solved. It is known that the Galilean satellites of Jupiter Ganymede, Europa and Io move so that the periods of treatment are as 4:2:1. The newly discovered planet e, b, c in exoplanetary system Gliese 876 move in the same way. But equality of the periods implies relations orbital radii (Kepler's third law). Thus, the equality of the relative orbital radii in systems of Jupiter and Gliese 876 is a consequence of 4:2:1 orbital resonance in these systems.

 

The solar system has many orbital resonances (http://quibb.blogspot.com/2010/04/orbital-resonance.html). This phenomenon has not yet been explained theoretically. But the presence of orbital resonances for planets and moons in our planet system to suggest that orbital resonances exist in other planetary systems.

 

Here is a table of the relative resonant orbits:

The numbers in its cells are calculated by Kepler's third law:

where n-number of the column, m - row number.

 

Using the table, we can know whether the two planets are in a state of orbital resonance. Take, for example, Jupiter and Saturn, the orbital radii are equal, respectively, 5.20 and 9.54 astronomical unit. 5.20 / 9.5 = 0.545. This number is very close to the tabulated number of 0.543 at the intersection of the fifth row and second column. Hence the periods of Jupiter and Saturn are approximately 2:5 (approximate 2:5 orbital resonance).

 

Note that the number of rows 3,4,5,7 in a comparative table of six systems are very similar to the bold numbers in Table resonances. The numbers in row 9 of comparative tables are also close to the value:

for the resonance of 1 / 12.

Edited June 25, 2011 by KrupS

[Moontanman]

This apparent discrepancy would seem to be the result of a sampling bias, "the low hanging fruit" so to speak. The ones we have discovered so far are the easiest ones to find, big planets close in the star are easier to find than small planets close in with big planets far out like our solar system. Once we get the ability to find the smaller planets close in we will know more about how the "average" planetary system is, it may very well be there is no average planetary system or that ours is odd but we just don't have the data to say for sure yet.

 

There is some evidence that our own planetary system was at one time wildly different than it is now with planets migrating in and out from the sun as they formed, there is just not enough data yet to know for sure.

[baric]

At first glance it seems that all this is true. But consider the system Gliese 581. We write the order of the values of orbital radii: 0.030, 0.041, 0.073, 0.146, 0.220, 0.758. Multiply this numbers by 23.65. Obtain a series of numbers: 0,71, 0,97; 1.73, 3.45, 5.20, 17.9. What is it?

 

Comparable to the orbital radius of planets in the solar system:

0.71 ; 0.97 ; 1.73 ; 3.45 ; 5.20 ; --- ; 17.9

0.72 ; 1.00 ; 1.52 ; ---- ; 5.20 ; 9.54 ; 19.1

 

As you can see, there is an obvious similarity, which confirms that planetary systems are created for one scenario.

 

I disagree. Look at the arbitrary decisions that you have made:

 

1) choosing to align the first Gliese 581 planet with Venus instead of Mercury (the 23.65 factor)

2) ignoring the large 14% discrepancy between Mars and its Gliese 581 analogue

3) ignoring the absence of a solar analogue to the 3.45 radius

4) ignoring the absence of a Saturn analogue in the Gliese system

 

Summary: you arbitrarily make 4 manual fits to establish a relationship over 6 points.

 

It's not a convincing approach, imo

 

 

 

Note that the number of rows 3,4,5,7 in a comparative table of six systems are very similar to the bold numbers in Table resonances. The numbers in row 9 of comparative tables are also close to the value:

for the resonance of 1 / 12.

 

The orbital values are 0.186, 0.191, 0.195, and 0.196

 

The orbital resonance for 1:11, 1:12 and 1:13 are 0.181, 0.191 and 0.202 respectively.

 

This means that 3 of the 4 values are actually in between resonances and do NOT fit.

Edited June 25, 2011 by baric