So how fast are we actually moving?

  • Thread starter Nexus555
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In summary, it is not possible to determine the exact speed of the Earth due to the constantly moving universe. Velocity is relative and there is no absolute frame of reference. It is possible for an object to have a relative velocity of 0 m/s in one frame of reference, but still be moving in another. The speed of light is considered the universal speed limit and it is not possible for an object to travel faster than this speed. The true speed of an object can only be determined using different reference frames and taking into account their directions. The cosmic microwave background radiation can be used as a reference point to determine an object's velocity relative to the universe.
  • #1
Nexus555
58
0
Ok I'm having trouble trying to figure something out. There will be a series of questions in this post.

First of all, how fast exactly is the Earth moving? Our average orbital speed is around 30,000 mph (correct me if I'm wrong) around the sun. The sun orbits around the center of our galaxy at approximately 217 km/s, so about 485,415 mph if my math is correct. And right now it's not exactly known, but the Milky Way is approximatley hurling through space at around 552 km/s or 1,234,789 mph So if I add it all together, that's about 1,750,204 mph.

I guess my question is: Are we really moving that fast, total? I guess it's kind of like being in a car, and you're going 60 mph, but in your perception in the car, you're at 0. If Earth is going 30,000 mph and the sun is pulling us around the galaxy center at 485,415 mph, and the galaxy is traveling us at 1,234,789 mph, are we actually moving that fast?

Another question, is there a such thing as absolute 0 as far as speed is concerned? Is intergalatic space at a "stand still?" Is there any way to determine a 0?

Also another question. If the speed of light is 186,000 mp/s (roughly) converted to roughly 669,600,000 mph, are we actually already traveling at a fraction of the speed of light?

Last one! : When a spaceship escapes Earth's gravitational pull and is in orbit around the Earth in space, is the spaceship actually traveling the 1,750,204 + their speed?

Thanks for whoever answers these questions!
 
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  • #2
Well, it is not as simple as adding velocities straight off without respect to their directions.

Your car is not going with a constant velocity in a straight line (curvature of the earth), so it isn't a perfect inertial frame of reference.

If your question is "Does the Universe move?" the answer is not as simple. How would you show or test it? A scientific hypothesis must be formulated in a way that allows it to be subjected to attempts to falsify it. "Does all books have 200 pages" is one, where as "Does God exist" is not a scientific hypothesis. If it is not a scientific hypothesis, it (generally) does not fall within the realm of science.

Velocity is relative and there is no special frame of reference where if an object has a relative velocity of 0 m/s with respect to that frame of reference is defined to be at absolute rest.

You cannot travel faster than the speed of light in any frame of reference according to the theory of relativity because that would demand an infinite amount of force.
 
  • #3
Nexus555 said:
Ok I'm having trouble trying to figure something out. There will be a series of questions in this post.

First of all, how fast exactly is the Earth moving? Our average orbital speed is around 30,000 mph (correct me if I'm wrong) around the sun. The sun orbits around the center of our galaxy at approximately 217 km/s, so about 485,415 mph if my math is correct. And right now it's not exactly known, but the Milky Way is approximatley hurling through space at around 552 km/s or 1,234,789 mph So if I add it all together, that's about 1,750,204 mph.

I guess my question is: Are we really moving that fast, total? I guess it's kind of like being in a car, and you're going 60 mph, but in your perception in the car, you're at 0. If Earth is going 30,000 mph and the sun is pulling us around the galaxy center at 485,415 mph, and the galaxy is traveling us at 1,234,789 mph, are we actually moving that fast?

Another question, is there a such thing as absolute 0 as far as speed is concerned? Is intergalatic space at a "stand still?" Is there any way to determine a 0?

Also another question. If the speed of light is 186,000 mp/s (roughly) converted to roughly 669,600,000 mph, are we actually already traveling at a fraction of the speed of light?

Last one! : When a spaceship escapes Earth's gravitational pull and is in orbit around the Earth in space, is the spaceship actually traveling the 1,750,204 + their speed?

Thanks for whoever answers these questions!

This is impossible find out the TRUE speed of earth. In order to find the true speed of anything you must know the absolute reference frame, but in a universe that is constantly moving how can you? At best we can only use reference frames from different objects to find speed. Example- you are sitting in front of your computer right now and reading this, relative to the Earth you aren't moving at all. Relative to the sun though, you are moving 30,000 mph in an orbit. Then you take the relative value from the center of the milky way and get another value and then the center of the universe and get anouter value. The point is you can't determine the TRUE speed of an object.
 
  • #4
to do a proper vector diagram you need directions
as Earth orbit is at what angle to solar orbit in the galixcy
and the angle to the galixcy's direction
unless every vector is lined up it is not a pure addition
and some motion may cancel

so what are the vectors victor?
 
  • #5
Nexus555 said:
Another question, is there a such thing as absolute 0 as far as speed is concerned? Is intergalatic space at a "stand still?" Is there any way to determine a 0?

Also another question. If the speed of light is 186,000 mp/s (roughly) converted to roughly 669,600,000 mph, are we actually already traveling at a fraction of the speed of light?

You obviously realize that speed and velocity are relative things. The closest we can come to determining our velocity relative to the universe at large, is to measure the temperature of the cosmic microwave background (cmb) radiation in all directions.

An observer that measures the average temperature to be the same in all directions can be considered as at rest relative to the cmb. As determined by COBE and WMAP, we are moving in the order of 0.1% of the speed of light relative to the cmb. This is due to the vector-summation of the velocities that you mentioned.

Jorrie
 
  • #6
How would you go about finding a stationary point in the universe? Or the "centre of the universe"? If we could find a point we knew was motionless or at 0, then we could know our speed relative to this right? Problem is finding that point in the first place? finding a speed relative to the CMB means only that you have found your speed relative to the CMB, not necessarily your true speed relative to a stationary point, you could make the assumption, that the CMB's speed is relative to a stationary point? But how would you prove you were right?
 
  • #7
hover said:
This is impossible find out the TRUE speed of earth. In order to find the true speed of anything you must know the absolute reference frame, but in a universe that is constantly moving how can you? ... The point is you can't determine the TRUE speed of an object.

I know your intentions are good, but this is misleading.

It is not simply impossible to find - simply out, there is no such thing as "true speed". It is a meaningless concept.
 
  • #8
Well cosmology is all very confusing to me.

First we had a wonderful and elegant theory, the general theory of relativity, where motion is relative, time is proper and space-time is defined by mass and energy. Then comes cosmology, where it feels like we are going back to Galilee, now we go back to absolute time, but of course we call it "cosmological time" and we replace the space-time geometry by some extra dimension on which space-time can expand.
And that is called progress. :tongue2:
 
  • #9
MeJennifer said:
Then comes cosmology, where it feels like we are going back to Galilee, now we go back to absolute time
Where did you get that impression from ?
 
  • #10
Back to Galilee?

MeJennifer said:
... Then comes cosmology, where it feels like we are going back to Galilee, now we go back to absolute time, but of course we call it "cosmological time" and we replace the space-time geometry by some extra dimension on which space-time can expand.
And that is called progress. :tongue2:

I know that you were writing this "tongue in the cheek", but I suppose somebody must complain about you calling cosmological time an "absolute time".

More seriously, I would like to know if the "extra dimension on which space-time can expand" is not applicable to a Schwarzschild vacuum as well? There space curves and as such also contracts and expands, depending on the reference frame, of course.

Jorrie
 
  • #11
Another question

I understand the speed is relative to the perspective. Here is another question I have concerning speed in space:

Let's say you have a space shuttle that launches from earth, and the spaceship begins to orbit the earth. The space shuttle's speed is based off of Earth's perspective. How could you make the space shuttle come to a "halt" (minus the speed they're going, and the speed of Earth's orbit) ? What I'm saying is, let's say the space shuttle decides to let Earth whiz by, and halt, and within 1 year the Earth will pass back around. So in the space craft's perspective, the Earth is traveling at 30,000 MPH.

How could this be accomplish? Would you have to turn the ship in the opposite direction of the Earth's orbit, and begin accelerating at a particular speed? If so, would it not be much less than a year, considering that both the Earth and the spaceship are traveling in opposite directions? So how exactly could you accomplish this (assuming that you could stay in one "place" while maintaining around the same proximity to the sun and Earth's orbital path.) It's just confusing, because it seems if you use force to try and slow the spacecraft 's speed, it's actually moving, if not faster, just in a different direction.
 
  • #12
If you wanted the shuttle to stop moving wrt to something other than the Earth, for example, the Sun or the celestial sphere, you would have to escape Earth's gravitational field (you'd have to leave orbit) and accelerate in the opposite direction from Earth's movement around the Sun. Eventually, you'd lose the momentum gained by the Earth. As this happens, you'll start falling towards the Sun. You'll need to fire rockets to prevent this.
 
  • #13
Okay your answer cleared that up.

Why would you start to "lose momentum?" I thought that once and object is in motion, it will stay in motion until acted upon by another force? Would the Sun's gravity be the agent (or force) that causes the lost velocity? Obviously it's what causes the ship to be eventually pulled towards it. But if you're traveling the opposite orbit of earth, it would seem if you're already traveling as fast or faster than Earth when you leave orbit, and travel through Earth's orbital path backwards, wouldn't that be enough to sustain an orbit around the sun (obviously you would eventually crash into earth.)

I guess the mass of the spaceship would determine if the spaceship would be pulled toward the sun, or continue it's speed until collison. Is this correct?
 
  • #14
Nexus555 said:
Okay your answer cleared that up.

Why would you start to "lose momentum?" I thought that once and object is in motion, it will stay in motion until acted upon by another force?
Sorry, that may have been a confusing statement. What I meant was, if you want to "stop" in the solar system, you will have to activate your rockets to negate the velocity gained by your start from Earth.

Note that you would need this velocity to stay in orbit - just as Earth does. If you lose this velocity, you'll fall into the sun.

Nexus555 said:
But if you're traveling the opposite orbit of earth, it would seem if you're already traveling as fast or faster than Earth when you leave orbit, and travel through Earth's orbital path backwards, wouldn't that be enough to sustain an orbit around the sun (obviously you would eventually crash into earth.)
Wait, when did we start traveling backwards? All we've done is stop. If you wanted to travel backwards, you'd need to keep blasting your rockets.

But yes, if you did, you'd eventually end up in an orbit the reverse of Earth's. And yes, it would be stable short term.
Nexus555 said:
I guess the mass of the spaceship would determine if the spaceship would be pulled toward the sun, or continue it's speed until collison. Is this correct?
No. The mass of the spaceship will not affect its fall. Just like the Space shuttle and a lost wingnut will fall toward Earth at the same rate.
 
  • #15
Nexus555 said:
Ok I'm having trouble trying to figure something out. There will be a series of questions in this post.

First of all, how fast exactly is the Earth moving? Our average orbital speed is around 30,000 mph (correct me if I'm wrong) around the sun. The sun orbits around the center of our galaxy at approximately 217 km/s, so about 485,415 mph if my math is correct. And right now it's not exactly known, but the Milky Way is approximatley hurling through space at around 552 km/s or 1,234,789 mph So if I add it all together, that's about 1,750,204 mph.

I guess my question is: Are we really moving that fast, total? I guess it's kind of like being in a car, and you're going 60 mph, but in your perception in the car, you're at 0. If Earth is going 30,000 mph and the sun is pulling us around the galaxy center at 485,415 mph, and the galaxy is traveling us at 1,234,789 mph, are we actually moving that fast?

Another question, is there a such thing as absolute 0 as far as speed is concerned? Is intergalatic space at a "stand still?" Is there any way to determine a 0?

Also another question. If the speed of light is 186,000 mp/s (roughly) converted to roughly 669,600,000 mph, are we actually already traveling at a fraction of the speed of light?

Last one! : When a spaceship escapes Earth's gravitational pull and is in orbit around the Earth in space, is the spaceship actually traveling the 1,750,204 + their speed?

Thanks for whoever answers these questions!



I think the current speed is 60 seconds a minute, or close to that.

What was your question?

(motion is relative, so we can't state that, unless you show us an absolute frame of reference)
 
  • #16
heusdens said:
I think the current speed is 60 seconds a minute, or close to that.

What was your question?

(motion is relative, so we can't state that, unless you show us an absolute frame of reference)

how about this one

X=Y=Z = 0 at the time of this post for the center of the earth
in units of your choise [miles, kM, fraction of a light year ect]

in one years time how far have numbers changed
adding in all known motion
[solar orbit around galixcy center + galixcy movement + any other]

or does nobody like vectors?
 
  • #17
ray b said:
how about this one

X=Y=Z = 0 at the time of this post for the center of the earth
in units of your choise [miles, kM, fraction of a light year ect]

in one years time how far have numbers changed
adding in all known motion
[solar orbit around galixcy center + galixcy movement + any other]

or does nobody like vectors?

What's your frame of reference?
 
  • #18
earth center at time of post as stated
aline N to pole and Z axis as commonly done

basic questions is simple we were at a point and moved
one year later how far

no out side frame needed
we are just tracking Earth for one year
 
  • #19
Ray, if Earth's centre is your frame of reference then after one year Earth has not moved at all. The Earth is still exactly where it was all along wrt to its center and will continue to be so for as long as Earth remains a planet.

You need to supply a frame of reference OUTSIDE that of what yoiu want to measure, such as the Sun, or the Galactic core or perhaps the local galactic cluster.
 
  • #20
DaveC426913 said:
Ray, if Earth's centre is your frame of reference then after one year Earth has not moved at all. The Earth is still exactly where it was all along wrt to its center and will continue to be so for as long as Earth remains a planet.

You need to supply a frame of reference OUTSIDE that of what yoiu want to measure, such as the Sun, or the Galactic core or perhaps the local galactic cluster.

quibbile quibbile quibbile
the current location of the center not the real center
I picked that to give a real feal to how far we move in a year
and picked a year to semi-cancil orbital motion around the sun
 
  • #21
Mr. Hubble would not be pleased. For according to his Law, relative to a galaxy far far away,...some 14 billion light years away...the speed of the Earth relative to it, when you consider space-time expansion, even at a constant rate of expansion ..is...,,,,,,,,,,, drum roll, please......
the speed of light !.
 
  • #22
ray b said:
quibbile quibbile quibbile
the current location of the center not the real center

No. You're missing the point.

...location of the Earth with respect to what observing point?

Just tell us where your observer is standing.

If you're standing on the sun, you'll get a very different value than if you're standing at the centre of the galaxy (and if you're standing on Earth - well - it hasn't moved at all, has it? It's still right under you.). There IS no objective reference point, you MUST PICK one.
 
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  • #23
an X Y Z grid can start at any random point
I see no need to tie it to any external point

the point I picked is the LOCATION of the center of the earth
at the time posted this directly related to how far the Earth will move in one year that is what I seek to know
I see no need to tie the grid to any other point

or any need for an external observer

if the Earth move one unit on x and one on y then it has moved that EXACT
amount without any external grid or observer needed
put that into units like miles and give a direction and you get mile per year and a direction of travel
that is all I ask
 
  • #24
The most widely accepted measure of our velocity with respect to the universe is called 'heliocentric cz' - the radial velocity of our solar system relative to the Hubble flow [about 370 kilometers per seconds]. See
http://www.astro.ucla.edu/~wright/cosmo_01.htm
for the gruesome details.
 
  • #25
Would we, in order to realize an "absolute 0" of movement, have to necessarily also have to find an "0" point in time?
 
  • #26
NOW THIS SIMPLE
and everyone is trylng to make it hard
or quible

all I want to know is speed AND direction
not Hubble flow or streaching of space or red shift effects
and don't see any need to tie the question to a fixed grid
as none really is out there
JUST SPEED AND DIRECTION for the year
lets apply the KISS rule here

as the milky way is moving to hit big A in the far future
what the basic question is,
suns orbit direction and speed vector in the milky way
at what angle to the whole milky ways track to hit big A and speed vector
I would guess we are moving ruffly at big A now not exactly but where ever big A will be when the predicted hit is to take place
but have no idea of the true angle between the sun orbit vector and the milky ways movement
 
  • #27
At 26,000ly distance, the Solar system is about 2/3rds of the way out from the core or the Milky Way. we orbit the MW counterclockwise (if we take Earth North as "up" for the galaxy as well) every 250My or so.

Andromeda is about 2 million ly away right now*, but we are converging. We will begin merging in about 4 billion years.

*The http://www.nasa.gov/audience/forstudents/5-8/features/F_When_Gallaxies_Collide.html" [Broken] makes a cool intuitive comparison. If our two galaxies were two music CDs (about right in diameter and thickness) then you would place them about 8 feet apart - quite close in galactic terms.

Andromeda can be seen almost in the plane of MW's disc - about 15 degrees below the disc of the MW.

I am unsure of the MW's North in relation to the SS's North. I think the'yre a roughly similar direction.


By the time we merge, the SS will have orbited the MW ~16 times. Because of this, it is kind of meaningless to ask where Andromeda will be when we merge. In that time, our whole galaxy including all our local stars will be nothing at all like it is now.
 
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  • #28
still want a speed and direction
 
  • #29
The question is still meaningless without external reference points.

The sun is a convenient local reference point, so we could start there. The Earth circles the sun one a year at a distance of about 1.5E08 km. The works out to about 30 km/s. The Earth's direction of travel, with respect to the rotational axis of the sun, is counterclockwise. Taking it a step further, the sun orbits the milky way. The distance from the sun to the center of the MW is roughly 3E13 km and it orbits it about once every 250 million years, which works out to a velocity of about 217 km/s in a counterclockwise direction [wrt to the polar axis of the MW]. For some linear measures, the Milky Way is moving toward the Andromeda galaxy at a speed of about 130 km/s as well as moving [along with the local group] at a velocity of about 600 km/s towards the constellation Hydra.
 
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  • #30
Nexus555,

We do not know of anything that is still in the universe (make that stationary otherwise I'll be drummed out of the forum..) and since we have no way of measuring how fast space 'flys by' we er.. simply cannot answer your question. Everything is expressed relative to something else, in this case we just don't have a fixed point to measure against. Even if you did use the current coordinates of the Earth as a reference we could not tell whether we were moving away at 1mph or 10 million.
 
  • #31
I guess ray has given us the required reference point. By 'The Big A' I presume he means 'The Great Attractor'.

So, the question becomes how fast are we moving toward the Great Attractor?

I think he also wants to know the orientation of the galaxy wrt our movement towards the GA, and the orientation of the SS wrt the galaxy.
 
  • #32
ray b said:
still want a speed and direction

the speed and direction were measured by George Smoot Berkeley team quite a long time ago and have been confirmed ever since as more and more data comes in

but he was already on the money as of around 1977!

and he didn't even need a satellite or anything, he did it (or his team did it) just using U-2 spyplane aircraft. Flying out of Moffat field near SF, and also out of someplace in Peru

beautiful measurements with simple resources. maybe i can get a link
 
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  • #33
Whoah! Ned Wright says that some other people measured it using balloon-borne instrument even before Smoot's team did it with U2 aircraft.

http://www.astro.ucla.edu/~wright/CMB-dipole-history.html

But on brief inspection it looks like the earlier team was somewhat off on the speed. Smoot got very close to the figure later confirmed by COBE (1990s) and WMAP (2000s) satellite measurments.

I'll try to find the Smoot website with the U2 pictures.
Here is a Smoot U2 page
http://aether.lbl.gov/www/projects/u2/
NOTICE THE STAR MAP WITH THE CONSTELLATION LEO

In any case the DIRECTION of the solar system's travel is the same direction as currently occupied by the constellation Leo. It is away from the Great Attractor, which is kind of irrelevant as a landmark. Of course we are orbiting Milky center, and Milky is part of Local Group and Local group is falling towards Virgo Cluster and Virgo Cluster is falling towards HydraCentaurus direction "Attractor" but all those complicated motions are not what matters. and not what cosmologists want to know when they have to adjust measurments to compensate for solarsystem motion.

When cosmologists compensate for solar system motion the vector they use is approx 368 km/sec in direction of Leo (you can find the precise coords in Ned Wright site)

and that was what Smoot found with the U2 aircraft (approximately)
 
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  • #34
Back in 2003 I was discussing this kind of thing with, among others, Chroot and I wanted to know how fast Milky was going towards the Great Attractor or in the Hydra-Centaurus direction.

So I hunted around and found a peer-review journal article that gave coordinates and a speed IIRC around 600 km per second.

I posted the figure and the link.

But that does not mean that Milky is approaching Big A at 600 clicks!

In largescale astronomy speeds are typically relative to the CMB

The astronomers had determined that Milky, or the Local Group which is roughly the same speed, is going IN A CERTAIN DIRECTION AT A SPEED OF 600 CLICKS RELATIVE TO CMB.

That doesn't tell about our speed relative to Big A, because Big A itself could be moving in any direction whatever and we wouldn't know.

So Big A, or the Virgo Cluster, or whatever is a BAD LANDMARK and most of the time people simply do not use it.

Another thing I found out was that Milky and the Local Group are not actually moving towards the Great Attractor! Only very roughly. they are not even headed anywhere in the constellations of Hydra and Centaurus!

The coordinates of Local Group velocity vector are in a small Southern constellation called Crater, the drinking cup.

That is something you can see in the sky, in our latitude, in the summer.
and it marks the direction that our Local Fleet of a dozen or so galaxies is really going.
 
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  • #35
Full circle?
 
<h2>1. How fast is the Earth moving through space?</h2><p>The Earth is moving through space at an average velocity of 67,000 miles per hour or 107,000 kilometers per hour. This is the result of its rotation on its axis and its orbit around the sun.</p><h2>2. What is the speed of the Milky Way galaxy?</h2><p>The Milky Way galaxy is moving at an estimated speed of 1.3 million miles per hour or 2.1 million kilometers per hour. This is the result of its rotation and movement within the local group of galaxies.</p><h2>3. How fast is the universe expanding?</h2><p>The universe is expanding at a rate of approximately 46 miles per second or 74 kilometers per second per megaparsec. This is known as the Hubble constant and is a measure of the expansion of space over time.</p><h2>4. What is the speed of light?</h2><p>The speed of light is approximately 186,282 miles per second or 299,792 kilometers per second in a vacuum. This is the fastest speed at which energy, information, or matter can travel in the universe.</p><h2>5. How do we measure the speed of objects in space?</h2><p>The speed of objects in space can be measured using various methods such as radar, Doppler effect, and parallax. These methods involve measuring the distance an object travels over a specific amount of time to determine its velocity.</p>

1. How fast is the Earth moving through space?

The Earth is moving through space at an average velocity of 67,000 miles per hour or 107,000 kilometers per hour. This is the result of its rotation on its axis and its orbit around the sun.

2. What is the speed of the Milky Way galaxy?

The Milky Way galaxy is moving at an estimated speed of 1.3 million miles per hour or 2.1 million kilometers per hour. This is the result of its rotation and movement within the local group of galaxies.

3. How fast is the universe expanding?

The universe is expanding at a rate of approximately 46 miles per second or 74 kilometers per second per megaparsec. This is known as the Hubble constant and is a measure of the expansion of space over time.

4. What is the speed of light?

The speed of light is approximately 186,282 miles per second or 299,792 kilometers per second in a vacuum. This is the fastest speed at which energy, information, or matter can travel in the universe.

5. How do we measure the speed of objects in space?

The speed of objects in space can be measured using various methods such as radar, Doppler effect, and parallax. These methods involve measuring the distance an object travels over a specific amount of time to determine its velocity.

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