I was coming home from Pizza Hut tonight, and don't ask me why but while thinking about the earth's orbit a interesting question came to mind, how long does It take for our solar system to make a complete orbit around our galaxy? So while driving back ot my house I trying to make calculations, sadly they were way off, but after hopping on my computer did some some searching and right now the two most common answers I have found are two hundred million years, and no one knows. Of course the next question that comes to mind would have to how long does It take for our universe to make a complete orbit? Sadly I have come up dead on that answer , and most likely I don't think no one could answer that question. I would fathom a guess that orbit would have to be in the billions of years to make, which would mean that the universe has at least completed 2-3 times since its existence. One of the websites I stopped by at mentioned the Sun as completed 23 orbits in our galaxy alone which is 200 million years an orbit, and if you got your calculators handy you can see that how long earth has been around.

 

 

 

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I can see why Pizza The Hut would get you thinking about galaxy orbits and Universal orbits and all that. Happens to me all the time . First off, the Universe doesn't "universally" orbit, though there's a possibility our immediate galaxy cluster, the Andromeda Cluster, may have some orbit or rotational velocity to it. By the way, in a little while (universal time, which makes "geological time" look like a blink of an eye) the galaxy, Andromeda, will be chowing down on the Milky Way, devouring it, consuming it, like a snake to a rabbit. Don't worry, though, the humans will be either long gone or easily have the ability to re-locate by the time that happens.
Here's another fun question to ponder: During this galactic orbit, our star system dips below and then above the galactic plane. Over time a graphical illustration would look something like a sine wave. How long does it take for the sun to go from peak to peak (from the top of the cycle, to the bottom, then back to the top again)? As a bonus, where are we right now in that cycle?

 

 

 

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I don't really know the correct answer, but all bodies in space (including the solar system) have to follow Keplers' three laws of motion. In this case we are looking t the third one:

T^2=4*pi^2*R^3/(G*M)

So, to get the answer all you need are the distance (semimajor axis) from the Solar System to the center of Milky Way and the mass of the galaxy itself. Both pieces of data are pretty ambiguously approximated, but you should get an answer that is somewhere close to the actual value.

The largest spiral gets to the two Magellanic clouds, which are about 180 000 light years away from the center of the galaxy. We are about 2/3 that way, that is R=120000 lightyears*9,460,730,472,580,800 meters/1 lightyear=1,135,287,656,709,696,000,000 meters away from the black hole in the center of our galaxy. The mass of the Milky Way is approximated to be about 1.7*10^64 kgs. Thus T is about 220-230 million years. That is alot:) Although the Universe is about 13 billion years old, out galaxy is relatively new, it came to its steady state only about 5.6 billion years ago. Thus the Solar System has made about 24-25 revolutions around the galactical center during the whole time of its existence. So, roughly, the circumference of the orbit (assume it to be a circle for simplicity reasons) would be 2*pi*R=7, 133, 222, 724, 060, 704, 182, 201 meters, and that is that our orbital speed is almost 1,005,302 meters per second. To be more familiar to you that's 3,619,087 km/h, or 2,249,277 mi/h

As far as the movement of the galaxy itself comes - it cannot be determined as we don't know where the center of our universe is. And we cannot calculate the speed of our universe as we don't know, if it is even moving, or is staying static. Or both at the same time (which is more probable according to the Membrane theory)

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interestingly enough I was watching a progam on the history channel awhile back about the very thing, the scientists that were talking about this were saying that when this happen that it will be one heck of a light show among other stuff. Stars exploding, planets exploding, and other great stuff. However, I doubt humans will ever leave this planet as we rather spend money on killing people and blowing stuff up.




Well if the predictions are true that the universe is 13.7 billion years old then the exact center would be 6.85 Billion light years, and yes I know the problem is we have no idea where it begins or where it ends so it could be anywhere. We have so much to explore and yet little time to explore it.

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ugh I got lost while reading abminara's post I have never thought about this question but I have seen a documentary before in discovery channel which mentions that our solar system is moving away from the galaxy it is included. The system is currently on the outermost part of the galaxy (thus we have a view of the galaxy, as we refer to it as the milky way) and as it spins, it moves further away. Imagine in the future, the sky would be illuminated with a huge streak of stars and the entire milky way galaxy would definitely be seen in the night sky.

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You have all got a really interesting discussion going on, lots and lots of numbers and years. I think that I will have to go to pizza hut and then come back to this post to be able to talk with you guys about it. I wonder if its really all got to do with the crust.

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It's just a hypothesis. We are NOT on the edge of the galaxy at all, but it is proven that we've moved from about halfway in the arm of Orion to 2/3 away from the center. But the hypothesis cannot be proven as we cannot really see the earth (or solar system, if you prefer) from the side. The other hypothesis is that we will be going away from it, thus increasing our orbital speed and thus be pulled back in so that we'll be moving in a type of a sinusoidal motion. But that's also only a hypothesis that cannot be proven for the same reasons as the former one. And even if the first one is true - it will not affect as in any way, even if we "spin off" in some 5-6 billion years, other than the solar system would not be like a flat disc it is now (due to the high rotational speed), some planets might slightly change their gravitational angles due to the comets and asteroids passing by - or - other systems, but, i repeat, that will not affect the Earth in any way. Especiually considering the fact that our Sun is going to explode in 4.3 billion years, or that we will be probably sucked into a giant black hole formed by the collision of the centers of Milky Way and Andromeda in 3 billion years. In any ways, do you care? Assuming that every generation takes up 25 years to arrive (actually, about 23), none of the people living in that period will have even a portion of your genes, unless you marry your sister/brother, and so do your children, then their children, etc. This might only work out for some african tribes if they manage to keep up with the tradition for 120000000 (yes, those really are seven zeroes after twelve) generations. The only way out of this dead end is to "jump off" our planet some time before that happens to another safe world. I'm sure, in three billion years mankind will have the technology to do so.

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Pizza Hut is a sagely place *nods*

Those are some interesting questions you pose. On the universe question, I suppose it depends on which theory of the universe you go with If the universe is infinite, than it could never make a complete revolution because the distance any point along the edge would have to travel would be infinite.

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OFF TOPIC

AHAHAHA I am sorry to go off topic but the pizza hut thing is just hilarious to this current discussion .

ON TOPIC

Here is a top view of where we are in the Milk Way



and from what I read we at 30,000 light years from the center, and also I would agree that our solar system is moving away while our galaxy and the Andromeda galaxy are getting getting closer. Since we will not be around unless we can slow down the aging process, or put our mind and souls in to AI machines. As for the genes I find that a bit interesting although its simple math of cutting the genes in half as this diagram will show

Grand Parent (100%) 1st Generation
Parent (50%) 2nd Generation
Me (25%) - 3rd Generation
My Kid (12.5%) 4th Generation
My Kid's Kid (.0625) - 5th Generation
20th generation (0.00019073486328125)

Now I may be missing something with this math but it would seem that the grandparents genes will still be there regardless who your parents are. It would just be a fraction of what it used to be 19 generations ago. Either way a part of you will be there when the apocalypse happens, hopefully in 2012 like the Mayans mention .

Of course I only can imagine what the world would be like in 2011 when everyone starts that mental countdown waiting to see what happens.

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Your math is right and, theorethically, that is what should be happening. But, as the cells divide to give chromosomes (and thus your genetic code) to your offspring, they get "tired" and somewhere around 7th generation normally with the standart deviation of 1 generation your genes are being replaced by those of your kids, and their kids, who already have half of what you do. Nobody really knows as to why does not the genetical information transfer forever, but that's just the way it is.

How the hell did we get to this?^))

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