Where the earth is going WRT to "0,0,0"?

Just one point, if the universe is expanding, why is our galaxy on collision course with Galaxy Messier 31 (Andromeda).

All i have said is said by scientists.

there are so many Contradictions

This another question?

rakesh_semwal, when you wrote: "Assuming the centre of earth at the point "0, 0, 0" at this moment (10.00 GMT date Nov 14^th 2006) what will be our position at 10.00 GMT on date Nov 15^th 2006", you implied a geocentric coordinate system. In this coordinate system, Earth will stay at "0,0,0" forever!

Your main question: "… why only certain things like galaxies. Black holes etc, why not pole star going far from sun. And so on. Is there any size limit?"

Firstly, gravitationally bound structures, like the solar system, our galaxy and our local group of galaxies do not take part in the universal expansion. Our cluster and super-cluster might, but the rate relative to us is so slow that it is not measurable against other peculiar movements. Why? - Because these intergalactic distances are still too small on a universal scale.

It is only at vast distances of more than a hundred million lightyears that the expansion of the universe becomes readily detectable. It is galaxies in other super-clusters that really speed away from our galaxy.

So do not worry, we are not drifting away from the Sun and the Sun is not drifting away from the Milky Way!

This is the answer I get every time. We stay at 000

Probably in simple terms this is because our space is also expanding as scientist says.

Let's assume a one more virtual superimposed space that is stationary and not expanding with our real space.

Now consider these coordinate inside this virtual space .Which behaves in true geometrical terms. And our space is still working as usual.

I hope now I should be able to get the direction of earth. Can I?

Do we consider two separate planetary systems gravitationally bound or they are independent from each others? If they are independent then why don't we observe any receding in between them? Yet it may be low as 10meters a years.

I have one more question for right now.

If two far distant galaxies are receding from each other at the speed that is proportional to there distance, means they not only receding but also have some acceleration. But if we go by simple physics a continuously accelerated body will eventually catch infinite speed.

Where as at other side we keep on saying that nothing can accede speed of light.

rakesh_semwal, maybe the reference frame you are after is the so-called "CMB rest frame". This is an inertial reference frame where the Cosmic Microwave Background (CMB) radiation has the same average temperature in all directions.

Earth, the Sun, the whole galaxy and in fact our super-cluster are all moving very fast relative to this reference frame (many hundreds of Km/s). I suppose one can choose your 0,0,0 point of the CMB rest frame to momentarily coincide with Earth's center. Now Earth will be going places at a rate of 100's of Km/s relative to 0,0,0!

On your final question, read again what I have said before (post #3) about the scales at which the expansion is noticeable.

Jorrie,(Guru)

My question is if the receding speed is proportional to the distance between two galaxies. Then in the case of two galaxies or clusters, which are at distance that is approaching to infinity.

Don't you think the speed is also going to approach infinity? And approaching infinity speed means much higher then 300,000 km/s.

Wow, I am not exactly sure what your question is, but that never stops me from answering. The Earth orbits the Sun. The Sun orbits our galactic center at an orbital speed of 241 km/s. Our galaxy, the Milky Way (who comes up with these names anyway?) is also in motion, but I don't know the exact vector coordinates.

Then again, it depends on your inertial reference point! As Earthlings we initially used Earth as that reference point, then the Sun… Heck, even the Sun is not moving in a pure orbit. The planets (primarily Jupiter) cause the Sun to sort of wobble back and forth. So, even though it orbits the galactic center, the Sun moves like a Slinky around the center of mass of the Milky Way. Other stars affect the Sun's motion, too.

So, what inertial reference point should we use when speaking of the Milky Way? Where is the center of the universe? While it is true that Andromeda is moving toward us, don't expect the doorbell to ring anytime soon! The velocity that it is moving is a mere 130 km/s. At that rate it will be about 5 billion years. That's plenty of time to get the carpets cleaned.

However, Andromeda and the Milky Way are not a significant player in the universe. The two us are simply two points in a sea of billions and billions (Note: the writer wishes to point out right now that Carl Sagan never said that and therefore I am not plagiarizing him) of other galaxies. Most are receding from us at higher rates than Andromeda is overtaking us. I don't know why Andromeda is in such a hurry, so please don't ask. We (Andromeda and the Milky Way) are part of a larger cluster of galaxies called the Local Group that are sort of traveling in a pack (much like a motorcycle gang after a long evening at the bar). There are some gravitational influences I would imagine that keep our Local Group together and interacting. The Local Group is moving toward the constellation Hydra, but I don't know why. Perhaps it is the next seedy space bar that our "motorcycle gang" is heading for.

So the velocity and vector of the Milky Way is, to use a pun, nebulous! It depends of what your reference point is and there are no "mile markers" on the highways of the universe that provide absolute coordinates. The best we can do is try to map the positions of other galaxies and their vectors and try to draw a larger 3-D image of as much of the universe as we can.

Also, the Pole Star, Polaris, is located within the Milky Way. It's position appears to move because both of us are in orbit inside the Milky Way and have different orbits.

There are black holes within the Milky Way and there are black holes outside of our galaxy. When astronomers speak of objects receding from us, generally, those objects are not part of our galaxy or the Local Group. Space and the matter that occupies it is not homogonous in nature. Rather, matter is scattered in clumps. This goes for galaxies. If you ever looked at a 3-D map of the known universe you will see that it has a structure and not evenly spaced out. While the universe is expanding, these clumps of galaxies are interacting with each other and their gravity is constantly pulling and tugging on each other to form groups of galaxies that in some cases cross paths to produce some remarkable results.

Finally, the forth dimension is really time. Think of it this way. In 3-D space we have an X, Y, and a Z coordinate. That represents three dimensions. Time, which describes motion, is the fourth. The 5th dimension is well known to be the dimension where socks go when you put them into the clothes dryer. There was a band with that name, but repeated raids of their homes and stage rooms have not turned up any socks. It is likely that the band is neither that dimension nor are they from that dimension. What a sham.

Anonymous Hero wrote: "If you ever looked at a 3-D map of the known universe..."

A 3-D map of the known universe would be really cool. Do you know of one? I'd love to see it!

All I can say is search. I think what I say was a television program and not on the web. It was impressive.