“Hope is not the conviction that something will turn out well but the certainty that something makes sense, regardless of how it turns out.” -Vaclav Havel
When you take a look at the planets in our Solar System, one of the most striking features about them is that they all orbit in almost exactly the same plane.
Image credit: Joseph Boyle of quora, via http://www.quora.com/How-close-are-the-planets-of-our-solar-system-to-b….
It didn't have to be this way, of course; you could imagine a scenario where the planets swarmed in a great, random sphere around our central star. After all, gravity work the same in all three dimensions, and farther out -- in the Oort cloud -- bodies do exactly this.
Image credit: Pearson Education.
So why do all the planets orbit in (almost) the same exact plane? Find out on this week's Ask Ethan!
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What about dark matter? Once the dust and gas get accreted into planets, they should be able to scatter dark matter gravitationally. Or at least scatter a fraction of it. That scattering should happen in galaxies too.
@David Whitlock #1: In principle, sure, but you're getting tripped up by the quantitative question. The density of dark matter in the galaxy is tiny, only about five times the density of empty interstellar space. Since dark matter is virialized, jike the atmosphere in a room, the particles are moving in random directions at the galaxy's orbital speed, about 200 km/s. Since the orbital speed around the Sun is only 18 km/s at 1 AU, there's no significant or correlated local effect on dark matter.
I find this extremely interesting. Is this planar arrangement a common phenomenon throughout space or something unique to our solar system?
No, it's common throughout the universe.
I've never looked at planets this way or realized that they are all in the same plane. This is truly amazing ! Can i just ask a stupid question. What is meant by the "Oort cloud" ? Where is it ? What is it ? How does it contribute to this finding ? Basic stuff like this.
15026559
I'm curious as to how this applies to our dwarf planets, I assume they take on similar orbital patterns?
u14341647
"They’re going to collapse in one (of the three) dimensions first"
What will cause the matter around the star to go "splat" , is it because of the asymmetry of the gas cloud ?
Referring to the Nebula hypothesis, I know that our planetary system was formed by cosmic gases and dust clouds, now I would like to know were these cosmic gasses and dust clouds already on one plane or did the planets begin to orbit on the same plane after their formation?
A bit of both. Those that weren't on the plane were smacked about more and therefore either broken, absorbed or left.
The disk formation is a general absolute when you have a roughly spehrical system that collapses. There will always be *some* anisotropy, and that will percolate up into a disk structure.
"Can i just ask a stupid question. What is meant by the “Oort cloud” ? Where is it ? What is it "
Google would provide much more answer, but the short version is "the outer remnants of debris collapsed from the protoplanetary systems", "Around 50,000 AU around the sun", "A lot of very large ice chunks". Halley's Comet is a late capture long period comet such as you get from the Oort cloud.
Google it is best.
This is very interesting!
If they are in the same plane and formed by the same cosmic gases and dust clouds, then what is the determining factor of a planet having life and being lifeless?
May I ask what is the significance of the planets being in the same plane?
Whether life starts, #11.
That's all we know.
I believe we should look at the shape of galaxies to answer this question. The majority of galaxies are disc shaped and the rest are spherical. This indicates the preferred shape of the orbits, which mimic their galaxy's shape. It could also be because planets orbiting with large angles to one another could create instability in other planet's orbits which could cause planets to leave their normal orbits because of the change in energy and collide. But I am unsure of how this could be possible as I understand that a massive quantity of energy will be needed to make this happen so it seems very unlikely. But then if this is not the reason for planets orbiting in the same plane, what is?
If you're not sure how something can happen, then don't say it's happening.
@ Alri Rtcher i agree with you . truly a massive quantity of energy is needed .....but the problem would be where to get such energy . taking it from a different perspective ...if we are to consider Gravitation ... the forces these planets exert on each other ,wouldn't it be enough energy ?
What is the significance of the planets being in the same plane? What would change if they were not in the same plane?
This is a very interesting question. I have never looked at planets and the universe this way. Will we ever know the answer to this question. I believe that everything in the universe was created by God and nobody will ever know why everything is the way it is today, but Him. We can look at everything and admire it, but i think that we will never really get all the answers to our questions.
Well the question of why, is a bit tricky. Tricky because we all have different opinions of HOW the solar system came into existence these beliefs (scientific or not) provide the answer to your question.
The inclusion of "hope" for me makes it less scientific. Famous scientists say that because a law such as gravity can exist on its own; the universe can and will create itself from nothing. Meaning the universe exists the way it does because it needed to exist. So why they are all in one plane? They needed to exist like that and maybe they are all interdependent on each other. Please correct me if I am incorrect.
@Wow, it is clear in my comment that these things can possibly happen as I have used the word 'could' not 'would'. I am thus seeking an explanation or further development of my idea.
u15089152
And it is clear I said that you should not have made a comment saying it could happen if you admit you don't know how it could.
It is a null statement to do soi.
This isn't in ANY WAY countered by claiming that you said it could not would. Indeed you don't know it could, YOU ADMIT THAT.
So you do not know it could, yet you claim it could.
This is not something you can do. Not could, not would, unfortunately, did does apply, but it's not something you can do.
Find out HOW IT COULD, *then* you can claim it could, based on that process. that process can be explained to be wrong (or not), but you have to have one proposed before you say could or can.
Does this same concept apply to planetary and asteroid belts but on a smaller scale?
Does this concept apply to planetary and asteroid belts but on a smaller scale?
An interesting question that I've never really thought about.
Another interesting question that can be derived from this question is: "if our planet moved around the sun as an electron moves around an atom, when viewed as a particle and not a wave, would life on earth be the same as it is today?"
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An answer to #6, BN Misselhorn, this doesn't apply to dwarf planets as Pluto orbits the sun at a plane of about 45 degrees ... somewhere around there
15277242
re:25: the electron doesn't orbit like the earth orbits the sun.
If an external force where to be exerted on one of these planets say in the form of a meteor impact and the planets orbital lane changes would there be corrective forces or will it simply keep spinning in its new orbital?
To my above comment u15046746
Interesting question indeed. From what I have learned in Geography, is that they rotate in the same plane simply because the angular momentum of these planets came from the same starting accident. This makes the planets to orbit closer to the plane hence they have about the same rotation axis. u14248043
@AC van Zyl, it would probably change permanentely. The orbits are aligned because of processes that happened when the planets were created and not because of forces currently active.
15007015
what would happen to the life on earth if the planets were not in the same plane?
U15254632
re: 27
That's why I said "if" in my question, I'm trying to understand the question better and would appreciate constructive responses
u15277242
re #31, since it doesn't arise, the query following never needs to be answered.
This is a very interesting blog and quite a thought provoking question. Could it possibly be due to the attraction of all the planets to the sun that causes them to be slightly aligned in the almost the same plane?
@32;
They are not strictly on the same plane even now. For a neat graphic of it, see also here (see second graphic). They are pretty close to being on the same plane, but not exactly on the same plane.
So to answer your question: nothing would happen. We know this because we already live in the sort of solar system you hypothesize.
@u15074511 #35: Why not actually *READ* the article? you might discover that it answers the question, so you don't have to make uninformed guesses.
Michael, the problem is that you think they're posting for some concrete reason. There is no purpose to their posting.
I find this a very interesting topic of conversation and have alwyas had a passion for the galaxy and stars.
Like previous comments I have read I have many questions that I would love asnwering but know that would take forever so would just like to know some key concepts.
Is this set up unique to just our galaxy or are there other set ups like this and how many planets are actually know for a fact today?
I would also like to know if this happening will continue to occur in the future or if it will change and if so due to what reason? Does all the pollution created by humans on Earth and released into space effect this in anway?
Please can people get back to me on what the main reasons are for this alignment of the planets and if it happens for any reasons and benefits?
If you're talking about 'planar' solar systems, the set up is almost certainly not unique, instead its likely very common. That's because the physics behind why it happens would apply to most clouds of particles coalescing under their own gravity. This is also why we see many such 'planar' galaxies too.
Yes, and hopefully my answer above helps you understand the "why."
No, because the scale is all wrong (our impact is too trivial), Forget our pollution, we could drop the entire Earth into Jupiter and it likely wouldn't affect Jupiter's orbit.
Oops I see my second answer is very unclear. Planar solar system formation is very likely happening and will continue to happen in the future, because the physics behind why it happens etc...
What causes the death of stars?
re:42
To u15017568
The death of stars is primarily caused by lead and other heavy metals building up on the outer regions of a star. Stars can fuse 2 hydrogens into helium which eventually leads to lead forming through this nuclear fusion process. This process generates a lot of energy which is why stars are so hot but it causes a star to become too heavy and collapse once to many heavy elements form.
Hope this helped, I may be wrong and someone may have a better explanation but i think that's the gist of it.
@#42 An article I rsad says stars "die" when they run out of hydrogen that it can use to make helium. But you can read more at http://www.universetoday.com/24186/how-does-a-star-die/
Just a nitpick @43,
Lead is NEVER reached by fusion processes within stars. It is true that once hydrogen fusion stops, the core of a star collapses resulting in higher temperatures, and that results in fusion reactions leading to heavier elements. That process stops at iron, though, since the iron nucleus has the maximum binding energy per nucleon. Any fusion to elements heavier than iron is energetically unfavorable. Elements heavier than iron form in supernovae and through neutron capture during neutron star mergers, not through normal stellar fusion.
@43,
Also, stars don't collapse because of the formation of heavier elements. Stars have the radius that they do because of the balance between radiation pressure resulting from the energy released by fusion and the gravitational force. Stars collapse when the fusion process ceases. When hydrogen becomes depleted in the stellar core, for instance, a collapse will occur as fusion slows. However, that collapse results in higher temperatures and further fusion reactions. Once the fuel for these reactions is depleted, collapse and temperature rise occurs again. The process repeats until iron is formed, after which no further fusion can occur and the star collapses permanently. The fate of the star after this depends on the mass of the star, with the result being a black hole for the heaviest stars, a neutron star for less massive stars, or a white dwarf for lighter stars.
re:45
Thanks for the reply and the information.
You sound like you know a great deal on the subject, do you have a degree in astronomy?
@ #47
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@48,
Nope. I have a degree in chemistry, but I try to learn what I can about other sciences as well. I am certainly no expert on astronomy. If you read this blog for any length of time, you probably could have made that same post.
Although, I did learn about the maximum in the binding energy per nucleon curve during my studies in school, not on this blog.
Very interesting, I never really thought about it. I am wondering though whether the plane of our and every other solar system in our galaxy matches the plane of our galaxy, and then the plane of the milky way to other galaxies?
15016936
Re: #51 Is there anything in particular that makes you wonder about that?
Adam, the plane of the ecliptic is due to rotational speed up as things fall in. That means the effect is higher the greater the relative distance matter has to go to "fall in". The effect his fairly high for solar systems, since the plants fall in a small, but significant, ratio of their orbit around the sun to create the planet body. Much less for other solar systems within our galaxy, since their size is relatively smaller compared to the size of the orbit. And much much less for galaxies, which are different in scale again.
This, for example, is the reason why water doesn't go down the same way down the plughole, though synoptic scale weather patterns DO rotate a consistent way. The bath is just too small compared to the radius of the earth.
It is quite astonishing to believe the systematic orbits of our planets in this vast universe function so efficiently. I initially assumed that the planets in our solar planet were not necessarily in the same plane.
What can be said about the moons of these respected planets and how do asteroids and comets move along throughout our solar panel?
u15128033
I presumed that the planets orbited the sun at particular distances but in random planes with no systematic appeal.
If all the planets are in the same plane, why could Pluto not be regarded as a planet anymore?