Sorry for being ignorant on this subject and the physics behind it, but why do the planets in our solar system run along a flat plane? Is it for the same reason that the Milky Way (and many other galaxies) is disc shaped? And is the asteroid belt also along that plane or does it completely encircle the inner planets like a sphere? Could a future spaceship potentially just 'hop' over it to get to the outer planets?


<----wasting thursday time. tia

5/5/2011 10:54:24 AM

the universe is 2D

5/5/2011 10:56:42 AM

the universe is 4D

You will never understand it with your 3D mind

5/5/2011 10:58:34 AM

Don't the planets align periodically? So at least at some points in time, they have to be in the same plane. I don't know about all the time... physics ain't my deal yo

5/5/2011 10:58:45 AM

Also interstellar space travel is impossible.

5/5/2011 10:59:09 AM

i'm guessing because they formed out of the same event and the spinning action of that event puts them on the same plan. i have no idea though, but that would explain why pluto is not on the same plane because its basically got captured by the system and is not from the same event.

5/5/2011 11:00:03 AM

Serious answer to your question. The planets are on the same plane. Asteroid belt is just remains of a planet. So theoretically you could "hop" over it. But there is no known way to speed something up to the point that space travel becomes a legit possibility. /thread

5/5/2011 11:03:02 AM

Quote :

"Also interstellar space travel is impossible. "

nah, you just need a really big fuel tank.

5/5/2011 11:05:01 AM

Get up early one morning this month and you can see four planets all together just over hte eastern Horizon. Mars, Venus, Mercury, and Jupiter.


The solar system is disk shaped because of conservation of angular momentum. The Sun formed from the collapse of a giant molecular cloud, which had some non-zero angular momentum. As it collapsed, the rotation rate increased (like an ice skater). The spinning action drew the cloud into a disk shape, and the planets formed form that. The asteroid belt is generally disk shaped, but it'd cost a ton of fuel to try and fly a ship up around it instead of just going through it like we do now. The asteroid belt isn't really 'thick' with stuff.

5/5/2011 11:12:09 AM

^sounds like this guy got it about right. the nebula our solar system formed from had an angular momentum (was spinning) and formed a disk, and as dust clumped, clumps lumped, and lumps formed planets, they remained spinning in that same disk direction.

The asteroids are spread out like a disk and not a sphere. The thing is, when we see illustrations of the asteroid belt, it looks littered with asteroids all over the place. in reality, they are VERY spread out and present only a very small hazard for spacecraft moving through the area.

(and whoever said the asteroids were the remains of a planet is mistaken. there wasn't enough mass in the region to successfully form a planet, especially with Jupiter's gravity as an influence)

5/5/2011 11:26:07 AM

Ill add that the planets and shit are not perefectly in the ecliptic plane... I think the variance covers about 15 degrees.

5/5/2011 11:31:06 AM

The answer to all astronomy questions is. Your anus.

5/5/2011 11:32:47 AM

modlin and Smath74 are close but could use some refinement. This topic is really about stellar evolution and the genesis of our solar system - the dynamics of the cloud of gas that made us leads to a disk shape.

Quote :

"Is it for the same reason that the Milky Way (and many other galaxies) is disc shaped?"

It is exactly the same reason.

Here is how it goes:
1. The universe is made up or gas/plasma, which was there since the big bang or came from supernovas
2. Collisions (more of less friction) cause a certain amount of matter to clump together by the force of gravity
3. Imagine a river. There isn't particularly friction between two particles in it. But two rivers running into each other have friction. A net "river" is created in the shape of a disk spinning in the direction of the net angular momentum of the matter. It's not that it starts with much angular momentum, but as it becomes more compact it spins faster, so it collapses until it's the right size for this "river" to be stable.

Picture 3 hula hoops, and imagine that they have a direction. Now imagine they're all have the same center and are at right angles to each other... so like one horizontal, and 2 vertical that form a cross, and the center for all 3 is in the same place. Now, if these were instead streams of plasma, they would hit and fall inward. This happens until a small imbalance of more going in one direction versus another eventually wins out.

Note that this applies for the solar system, galaxy, and the rings of various planets too. It's just a matter of the dynamics of gas in the universe.

5/5/2011 11:46:14 AM

modlin and Smath74 sum it up pretty well. The maximum inclination to the ecliptic plane is Mercury, which is about 7 degrees, but it's the odd ball of the group. The other planets are all within a few degrees of the plane. So the correct answer (and the one I give to people) to the statement "hey, the planets are aligned!" is "yes... where else could they be?"

Also, I don't want to make a separate thread for this, but I figure anyone who clicks on a thread called "Astronomy Question" might be interested in knowing that the astrophysics group at NC State is hosting our semi-annual open house tomorrow night, at our observing site on Reedy Creek Road. Anyone is welcome to attend, and more details (map, time, additional info) can be found here:

http://astro.physics.ncsu.edu/Astro/openhouse/

Hopefully the weather cooperates

5/5/2011 11:54:53 AM

This may be the only nerd talk I enjoy.

Keep going

5/5/2011 11:57:06 AM

5/5/2011 12:00:24 PM

Quote :

"the universe is 4D"

isn't it 11D according to string theory?

5/5/2011 12:01:09 PM

^^^^ that's cool i didn't know there was an astrophysics group now (other than the research group). that link was a trip down memory lane. i actually managed to find the page that listed the astrophysics research program i was in the summer before coming to State http://wonka.physics.ncsu.edu/Astro/undergrad/reu00.html

too bad the actual presentation i made isn't still around. probably one of the first website i ever made, i'm sure it was awful

5/5/2011 12:08:14 PM

Interstellar space travel isn't impossible. It's quite easy, actually.

You simply discover where the force of gravity comes from. Then, you apply that force to your entire space vehicle but to a much greater magnitude. You will have to make sure you apply that force to each individual atom within the space vehicle and the passengers with equity to avoid an acceleration differential that would rip everything to shreds.

5/5/2011 12:08:40 PM

http://en.wikipedia.org/wiki/Magnetar

this is cool

5/5/2011 12:18:23 PM

indeed.

5/5/2011 12:26:26 PM

Quote :

"that's cool i didn't know there was an astrophysics group now (other than the research group)."

ha, well, when I said "astrophysics group" I meant the research group in the physics department. I'm a post-doc here, and once every six months or so I try to round up a few grad students and faculty to haul out our telescopes at the lab teaching site for an open house for the general public. We only have 8-inch telescopes, but if the weather cooperates we can usually see some pretty decent stuff...

To my knowledge, there isn't any sort of "astronomy club" or anything at the university (although I would not be the person to know, even if there was one...)

5/5/2011 12:26:34 PM

ah ok, i gotchya. that's cool about the open house stuff though. that was always one of my favorite aspects of being in physics to be honest - our SPS chapter at the time did a lot of science demos at local schools and set up booths at science fairs and stuff. http://www.science-house.org/ does a great job with that stuff too

5/5/2011 12:34:46 PM

Quote :

"The asteroids are spread out like a disk and not a sphere. The thing is, when we see illustrations of the asteroid belt, it looks littered with asteroids all over the place. in reality, they are VERY spread out and present only a very small hazard for spacecraft moving through the area. (and whoever said the asteroids were the remains of a planet is mistaken. there wasn't enough mass in the region to successfully form a planet, especially with Jupiter's gravity as an influence)"

IIRC, the total amount of mass in the asteroid belt is less than the mass of our moon. So imagine taking our moon, breaking it into chunks, and the spreading them out into a ring with a radius of 400 million km. Lot of empty space out there.

5/5/2011 12:36:14 PM

Quote :

"Interstellar space travel isn't impossible. It's quite easy, actually. You simply discover where the force of gravity comes from. Then, you apply that force to your entire space vehicle but to a much greater magnitude. You will have to make sure you apply that force to each individual atom within the space vehicle and the passengers with equity to avoid an acceleration differential that would rip everything to shreds."

Or you be Voyager 1.

5/5/2011 12:39:57 PM

V'Ger

5/5/2011 1:39:48 PM