How can three planets in our sky form a triangle?

[julianh72 (Julian)]

Originally Posted by xelasnave

I wonder why we have the incline.

Star systems are formed by the gravitational collapse of a cloud of gas and dust; as the material collapses in on itself, it retains its initial angular momentum as it forms a disc, and then the star and planets coalesce from that disk, so all tend to lie in a plane. However, the initial angular momentum of the gas / dust cloud is pretty random, so the inclination of star systems within a galaxy is pretty random.

Our Solar System happens to be aligned at an angle of about 63 degrees to the plane of the Milky Way, but other star systems are at arbitrary angles to our own - which is why we see some of them edge-on (which means we can see transiting planets or eclipsing binary stars), while others are more face-on to us.

[xelasnave]

Hi Sil,
Thank you for taking the time to present your understanding on the matters you addressed.
Alex

[xelasnave]

Hi Julian,
Thank you for your explanation.
Alex

[Eratosthenes (Peter)]

Originally Posted by sil

The solar system is really a pebble skipping across the lake of reality? So we have an incline to provide lift and not sink into the depths where cthulu awaits?

How do you know so much about Astrophysics?

[julianh72 (Julian)]

Originally Posted by Eratosthenes

How do you know so much about Astrophysics?

I dunno... Any description of the workings of the universe which doesn't mention the four elephants which are borne through space and time on the back of the Great A'tuin is obviously incomplete!

[Eratosthenes (Peter)]

Originally Posted by julianh72

I dunno... Any description of the workings of the universe which doesn't mention the four elephants which are borne through space and time on the back of the Great A'tuin is obviously incomplete!

Yes I have heard about that theoretical hypothesis. Surprised CERN or LIGO arent involved in some way.

Personally, I think 4 is not enough in Non-Euclidian space-time geometries.

[julianh72 (Julian)]

Originally Posted by Eratosthenes

Yes I have heard about that theoretical hypothesis. Surprised CERN or LIGO arent involved in some way.

I believe Ponder Stibbons (Head of Inadvisably Applied Magic at Unseen University in Ankh Morpork) heads up the leading research team in this field.

[AussieTrooper (Ben)]

Originally Posted by iasuka

Maybe I took it wrong, but my impression of the original question was that the TS wanted to know how come planets form triangle instead of a straight line. On other words, why planets in Solar system are not in the same orbit plane?

This problem is not as trivial as it might seem. Look at the rings of Saturn, for instance. It consists of billions of ice pieces all going in virtually the same plane. On the other hand, if you look at the planets' orbit planes - those are noticeably inclined, for up to 7 degrees for Mercury.

Interesting point. You could argue that such a high concentration of small objects would have many collisions, averaging out the orbits. Then again, the asteroid belt has a huge number of highly inclined objects.

[markbakovic]

sorry to gravedig. the answer is "the Nice II model".

i deadset love the cosmology pondering with an almost preset countdown timer to elephants and wizardry though. may i suggest space donkeys, as proposed by Noble (2007).

[edit]and in that Q & A link: follow up question 2 is a fantastic example of how to out "science" common sense and leave a kid thinking "well, that sounds like bollocks I'm going to believe in pixies now"... -"everything rotates anticlockwise when viewed from 'above' LOCALLY which is defined to be the direction from which rotation appears anticlockwise by convention" was the answer LeeH should have been looking for... [/edit][/rant]

[edit II] sil: vortex shedding of rotating spheres in fluid?. My guess (so not my field but I'll guess anyway whynot) is difference between star and BH is energy level of infalling particle: relativistic effects probably apply for BH, notsomuch for mainsequence yellow dwarf. also someone mentioned x-rays: remember that the soft x-rays generated by curving electrons are tightly focussed because relativity, so you get a tangential beam from an electron curving around near constant radius, but the emission of the x-ray obviously drops the electron's energy so it doesn't just emit another beam straight away: sound applicable? [/edit]