# Are planets in the same altitude level? [closed]

Maybe this has been asked with another name, but I didn't find it.

1) Are planets in the same altitude level?

2) What defines altitude in the space (universe)?

3) Is the universe a XYZ plane?

4) What keeps planets from orbit the sun in a 45º orbit from Earth's perspective?

Ascii graphical example:

                 +----------------------+
|                      |
|                      |
|      SUN             |
|                      |
|                      |
|                      |
|                      |
|                      |
|                      |
+----------------------+

+-------+     +----------+
|       |     |     VENUS|
| EARTH |     |          |
|       |     |          |
+-------+     +----------+

+------------+
| MARS       |
|            |
|            |


This tries to be a horizontal look.

• This is not really a world building question, is it? 1. No because 2. altitude is not really relevant concept for space 3. No. The usual model for doing math has three spacelike dimensions and one timelike dimension, so if you can ignore the time dimension it looks like XYZ. 4. Inertia. Planets formed, presumably, from a disk, and unless something disturbs their orbits, they'll stay in the same plane. Hope I understood your questions correctly. – Ville Niemi Jan 16 '15 at 15:05
• I think you are really asking if the planets of the solar system and the sun are on the same plane. It is something like this? – T. Sar Jan 16 '15 at 15:30
• @ThalesPereira Yes, I am asking if they are in the same level when you look horizontally with the sun centered. Then why it it can't be other way – JorgeeFG Jan 16 '15 at 16:27
• Too many misconceptions to list here. What on earth should we take from "Is the universe a XYZ plane?"?! – Lightness Races with Monica Jan 16 '15 at 17:27
• @James I would agree with you if the question didn't already exist on Astronomy, as JohnP pointed out. – HDE 226868 Jan 16 '15 at 23:49

It has to do with how the planets were formed, as the gas cloud that surrounded the sun coalesced when it was a protostar.

It is explained rather well here: https://astronomy.stackexchange.com/questions/130/why-do-the-planets-in-our-solar-system-orbit-in-the-same-plane

A protoplanetary disc is a rotating disc of gas surrounding a newly formed star. When the star is forming out of a molecular cloud, as it condenses it averages out random motion of the gas in favor of the net angular momentum of the nebula.

Conservation of angular momentum causes the ball of gas that formed the protostar to flatten out and take the shape of a disc (like a ball of pizza dough becoming a flat shape when spun, it flattens and spreads out).

1) Are planets in the same altitude level?

The planets orbiting our sun are all in the same plane. meaning they make a disc with rings.

2) What defines altitude in the space (universe)?

The closest I can think of what you mean is distance from the sun. closer and farther orbits

3) Is the universe a XYZ plane?

The universe is multidimensional, but yes basic space has the 3 basic axis.

4) What keeps planets from orbit the sun in a 45º orbit from Earth's perspective?

Some thing called the Invariable Plane

The invariable plane of a planetary system, also called Laplace's invariable plane, is the plane passing through its barycenter (center of mass) perpendicular to its angular momentum vector. In the Solar System, about 98% of this effect is contributed by the orbital angular momenta of the four jovian planets (Jupiter, Saturn, Uranus, and Neptune). The invariable plane is within 0.5° of the orbital plane of Jupiter,1 and may be regarded as the weighted average of all planetary orbital and rotational planes.