can someone explain to me why planets are always orb(-ish) shaped, its something to do with gravity right?
Every part attracts every other part. The net effect is that everything is pulled toward the center of mass. This naturally coalesces into a spheroid because it's the closest everything can be packed in a three dimensional shape.
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PiptheFairFrequently not in boats.Registered Userregular
can someone explain to me why planets are always orb(-ish) shaped, its something to do with gravity right?
essentially
there is a sweet spot where once you achieve that level of mass, along with centrifugal force, your mass essentially collapse in equally and you form a sphere
there are some asteroids in the belt that are very close to that mass
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AnosognosWho wants to playvideo games?Registered Userregular
Yeah, smaller things are lumpy because there just isn't enough force to crush them into a sphere.
The most perfect spheres in the Universe are (I believe) neutron stars because the gravity is so strong and thus the pressure on it's matter so vast that any imperfection is squashed flat!
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PiptheFairFrequently not in boats.Registered Userregular
The most perfect spheres in the Universe are (I believe) neutron stars because the gravity is so strong and thus the pressure on it's matter so vast that any imperfection is squashed flat!
neutron stars are so unbelievably dense it is almost not comprehensible
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AnosognosWho wants to playvideo games?Registered Userregular
edited February 2012
Even so, they're oblate if they spin fast enough to compress along their axis. And some of them spin pretty damned fast.
Anosognos on
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PiptheFairFrequently not in boats.Registered Userregular
Also, the Hubble views of the Carina nebula are just amazing. From the detailed images of Eta Carinae and its gas lobes to the massive pillars of gas and dust being carved by solar winds.
Those "antenna" on the top of the tall column and the shorter, thicker one to the left are streams of matter flowing from the poles of young stars inside the clouds.
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PiptheFairFrequently not in boats.Registered Userregular
Those "antenna" on the top of the tall column and the shorter, thicker one to the left are streams of matter flowing from the poles of young stars inside the clouds.
Even so, they're oblate if they spin fast enough to compress along their axis. And some of them spin pretty damned fast.
Yeah, I am just reading up on them now. Seems like they all spin, and the ones that spin at a slower speed are basically perfect sphere, but the faster ones extend along their axis. Makes sense, I guess.
Also I just read about Starquakes. Man, Starquake would be a fantastic superhero name, I am stealing that!
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AnosognosWho wants to playvideo games?Registered Userregular
Also magnetar. Even tho he'd just be a Magneto ripoff.
can someone explain to me why planets are always orb(-ish) shaped, its something to do with gravity right?
The real quick explanation is that yes it mostly has to do with gravity
The current model for planet formation has them forming at the same time as the star out of the same material. This means that the material which is spinning around the star gives the body its initial motion.
In order to maintain this motion with some stability the body must be mostly spherical. With liquids and gases this is relatively easy and is maintained by the balance between the rotational forces and gravity.
With rocky bodies this balance is maintained by collisions, and tectonics.
And you don't have to have a perfect sphere, just as long as your orbital motions are relatively stable over the period of your orbit.
Also, the Hubble views of the Carina nebula are just amazing. From the detailed images of Eta Carinae and its gas lobes to the massive pillars of gas and dust being carved by solar winds.
Those "antenna" on the top of the tall column and the shorter, thicker one to the left are streams of matter flowing from the poles of young stars inside the clouds.
This is a really nice nebula because normally we don't get to see these kinds of features because, well they're dark. But thanks to those big stars behind it illuminating it we get to see all that and more.
Also, the Hubble views of the Carina nebula are just amazing. From the detailed images of Eta Carinae and its gas lobes to the massive pillars of gas and dust being carved by solar winds.
Those "antenna" on the top of the tall column and the shorter, thicker one to the left are streams of matter flowing from the poles of young stars inside the clouds.
Why do moons go around a planet in the same direction as the planet spins? Is that even a thing?
Also, why are the planets and other shit around the sun all on sorta the same plane?
1. gravity essentially
2. during system formations ecretion discs are formed on different planes, and well newtonian physics, if nothing knocks them off their trajectory they will stay that way
+1
BeastehTHAT WOULD NOTKILL DRACULARegistered Userregular
Why do moons go around a planet in the same direction as the planet spins? Is that even a thing?
Also, why are the planets and other shit around the sun all on sorta the same plane?
First of all, Triton orbits the wrong direction around Neptune. With very, very few exceptions, celestial bodies in our solar system rotate in a clockwise direction. This is theorized to be the resultant spin from back when the solar system was accreting out of our planetary nebula.
If items spinning clockwise can be associated with the formation of the solar system it stands to reason that items with opposite spin would have to have come from outside the system. There is no mechanism as yet understood to explain the counterspin.
Why do moons go around a planet in the same direction as the planet spins? Is that even a thing?
Also, why are the planets and other shit around the sun all on sorta the same plane?
They usually do because it all formed from a disc of gas and dust. That's just Newtonian mechanics. Think of spinning pizza dough. It wants to flatten out into a disk. The planets themselves are going to be spinning the same direction they orbit as they're essentially like objects floating at the center of eddies in a very strong current. The moons that orbit them do the same thing.
There are exceptions. Moons that orbit the opposite direction of planetary spin are thought to be objects from elsewhere that were passing by and got captured by the planet's gravity. Venus spins retrograde, suggesting it actually got knocked end over end by a massive impact at some point.
Anosognos on
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PiptheFairFrequently not in boats.Registered Userregular
Essentially we are assuming everything behaved nicely when it comes to planetary body formations.
And if it didn't someone threw a rock at it.
We hope.
+1
BeastehTHAT WOULD NOTKILL DRACULARegistered Userregular
bro..
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AnosognosWho wants to playvideo games?Registered Userregular
We assume a lot of things. There's no other choice. It's when you assume more than is necessary that you significantly raise your chances of getting into trouble.
What's at the middle of Jupiter? It is gas all the way down or is there a tiny planet in there?
Idea is that it has a solid core made of the heaviest elements that have sunk down, surrounded by hydrogen that is under such intense pressure that it's become metallic.
Posts
It's a fun dream.
Fo' realz.
It's pretty to look at. Wouldn't want to go there.
Having learned about the horrors from astronauts and their instructors, I've lost all desire to actually ever go there.
Every part attracts every other part. The net effect is that everything is pulled toward the center of mass. This naturally coalesces into a spheroid because it's the closest everything can be packed in a three dimensional shape.
essentially
there is a sweet spot where once you achieve that level of mass, along with centrifugal force, your mass essentially collapse in equally and you form a sphere
there are some asteroids in the belt that are very close to that mass
neutron stars are so unbelievably dense it is almost not comprehensible
those become pulsars!
Those "antenna" on the top of the tall column and the shorter, thicker one to the left are streams of matter flowing from the poles of young stars inside the clouds.
send keith a message
Yeah, I am just reading up on them now. Seems like they all spin, and the ones that spin at a slower speed are basically perfect sphere, but the faster ones extend along their axis. Makes sense, I guess.
Also I just read about Starquakes. Man, Starquake would be a fantastic superhero name, I am stealing that!
The real quick explanation is that yes it mostly has to do with gravity
The current model for planet formation has them forming at the same time as the star out of the same material. This means that the material which is spinning around the star gives the body its initial motion.
In order to maintain this motion with some stability the body must be mostly spherical. With liquids and gases this is relatively easy and is maintained by the balance between the rotational forces and gravity.
With rocky bodies this balance is maintained by collisions, and tectonics.
And you don't have to have a perfect sphere, just as long as your orbital motions are relatively stable over the period of your orbit.
This is a really nice nebula because normally we don't get to see these kinds of features because, well they're dark. But thanks to those big stars behind it illuminating it we get to see all that and more.
man
I wish space actually looked like that
Also, why are the planets and other shit around the sun all on sorta the same plane?
1. gravity essentially
2. during system formations ecretion discs are formed on different planes, and well newtonian physics, if nothing knocks them off their trajectory they will stay that way
can you begin to comprehend how vast this expanse of sheer nothingness is
I fucking love magnetars.
http://scienceray.com/astronomy/triton-may-be-a-rogue-visitor/
They usually do because it all formed from a disc of gas and dust. That's just Newtonian mechanics. Think of spinning pizza dough. It wants to flatten out into a disk. The planets themselves are going to be spinning the same direction they orbit as they're essentially like objects floating at the center of eddies in a very strong current. The moons that orbit them do the same thing.
There are exceptions. Moons that orbit the opposite direction of planetary spin are thought to be objects from elsewhere that were passing by and got captured by the planet's gravity. Venus spins retrograde, suggesting it actually got knocked end over end by a massive impact at some point.
it contains all your pro-posts
And if it didn't someone threw a rock at it.
We hope.
No. No, I can't. It's.... big.
Idea is that it has a solid core made of the heaviest elements that have sunk down, surrounded by hydrogen that is under such intense pressure that it's become metallic.
forming supernovas are scary
Rocky bits that started the initial mass collection surrounded by ice is the general accepted answer.
So much fucking light pollution near central texas
like holy fucking shit
Just count how many Milky-Way's you can fit in there.
Also, yeah, anything near the San Antonio-Austin-Dallas corridor or east of there is pretty crap for star gazing.
Magnetic fields and hot plasma are hella crazy