# Q: How fast are we moving through space? Has anyone calculated it?

The original question was: Considering the spin of the earth, it’s orbit around the sun, the sun’s orbit around the Milky Way and the Milky Way’s journey through interstellar space, has anyone calculated our speed though the universe?

Physicist: The short answer is “yes”, and the long answer is “well… yes”.

The problem with motion is that “true motion” doesn’t exist.  The best we can do is talk about “relative motion” and that requires something else to reference against.  What you consider to be stationary (what you chose to define your movement with respect to) is a matter of personal choice.  The universe isn’t bothered one way or the other.

Relative to your own sweet self: Zero.  This sounds silly, but it’s worth pointing out.

Relative to the Earth: The Earth turns on its axis (you may have heard), and that amounts to about 1,000 mph at the equator.  The farther you are from the equator the slower you’re moving.  This motion can’t be “ignored using relativity”, since relativity only applies to constant motion in a straight line, and movement in a circle is exactly not that.  This motion doesn’t have much of an effect on the small scale (people-sized), but on a planetary scale it’s responsible for shaping global air currents (including hurricanes!).

Relative to the Sun: The Earth orbits the Sun at slightly different speeds during the year; fastest around new years and slowest in early July (because it’s farther from or closer to the Sun respectively).  But on average it’s around 66,500 mph.  By the way, the fact that this lines up with our calendar year (which could be argued to be based on the tilt of the Earth, which dictates the length of the day) to within days is a genuine, complete coincidence.  This changes slowly over time, and in several thousand years from now it will no longer be the case.  Fun fact.

Relative to the Milky Way: The Sun moves through the galaxy at somewhere around 52,000 mph.  This is surprisingly tricky to determine.  There’s a lot of noise in the the speed of neighboring stars (It’s not unusual to see stars with a relative speed of 200,000 mph) and those are the stars we can see the clearest.  Ideally we would measure our speed relative to the average speed of the stars in the galactic core (like we measure the speed at the equator with respect to the center of the Earth), however that movement is “sideways” and in astronomy it’s much much easier to measure “toward/away” speed using the Doppler effect.  Of the relative speeds mentioned in this post, the speed of our solar system around the galaxy is the only one that isn’t known very accurately.

Relative to the CMB: The Milky Way itself, along with the rest of our local group of galaxies, is whipping along at 550 km/s (1.2 million mph) with respect to the Cosmic Microwave Background.  Ultimately, the CMB may be the best way to define “stationary” in our corner of the universe.  Basically, if you move quickly then the light from in front of you becomes bluer (hotter), and the light from behind you gets redder (colder).  Being stationary with respect to the CMB means that the “color” of the CMB is the same in every direction or more accurately (since it’s well below the visual spectrum) the temperature of the CMB is the same in every direction (on average).

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### 40 Responses to Q: How fast are we moving through space? Has anyone calculated it?

1. kopernik says:

Our problems with system deficits of energy could be solved if we could capture the the differences in torque between two or more bodies.
For example, take a free standing ton mass on the surface of this planet and cause it to be slowed 100 mph (Don’t ask me how.) relative to the 1000 mph velocity of Earth’s surface. That resulting resistance or momentum could be translated into a form of energy. Of course the amount of energy to do that would be slightly more than the energy we could retrieve. But, if we let the mass catch up slowly with the surface speed, we might end up on the positive side of that energy equation.
What think ye? K
Perhaps we could play one momentum source against another –
[Intra galactic travelers use captured differences in cosmic momentum to propel their craft, but they are secretive about how it is done. ]

2. James says:

Why does relativity not apply to circular motion? Lets say…John is spinning in place at 98 revolutions per minute and Jane is beside him spinning at 130 revolutions per minute, when judging either of the individuals ‘speed’ wouldn’t johns speed be relative to janes and janes speed be relative to johns?, also implying both would be relative to a still third party? Obviously this would not work if John was spinning and Jane was running but if both are moving in the same manner why is it not relativity? We can add another element in there and say John was spinning at 98 rpm while standing atop a sitnspin spinning at 400 rpm. I’m no math wiz, hell I haven’t nor do I plan to graduate college yet I am an autodidact and have autism spectrum disorder and in my logic based thought relativity is present regardless of what direction an object moves in.

3. The Physicist says:

@James
The laws of relativity do apply to circular motion, it’s just that while velocity can’t be detected (which is what the post is talking about) acceleration can be.
If you’re flying through space at millions of miles per hours you’d never notice that it’s any different from sitting still. However, if you step on the gas pedal (accelerate forward) or on the brakes (accelerate backward) you will notice the pull. Similarly, when you move in a circle or in any way change direction you’re accelerating and will be able to tell the difference.

4. Scott says:

You neglected to mention Siamese cats. They seem to believe (and evidence supports the claim) that all humans revolve around them.

This answer will get a whole lot more complicated if it turns out “empty” space in fact has structure, as I believe it does.

5. Matthew says:

How does the fact that there’s a rest frame of the CMB square with the ‘no preferred frame’ tenet of SR?

6. Quantum Mechanic says:

Just out of idle curiosity, what is our heading with respect to the CMB? Or, conversely, where did we “come from” wrt/ the CMB? A constellation or galaxy reference would suit me fine.

7. The Physicist says:

In the direction of Hydra. Specifically, toward the “Great Attractor“.

8. Carefree Mathematician says:

Is it possible to use the CMB to find the approximate area in which everything in the universe originated from? Like, a place, or at least direction of birth. Given the Big Bang, things have been ex

9. Carefree Mathematician says:

Is it possible to use the CMB to find the approximate area in which everything in the universe originated from? A place, or at least direction of birth? Given the Big Bang, things have been expanding for quite some time, since the universe was very very small, so shouldn’t there be a “center of the universe,” a point so that the average relative velocities of all particles everywhere is zero? Or failing that, so that the average location of all mass everywhere is right there.

Also! I’ve seen that a lot of these posts begin with someone asking a question, where do they come from?
Thanks!! 😀

10. kopernik says:

You asked – Where did we come from?
(This is something I wrote about twenty years ago. It’s a little long so you may want to skip it.)
We Are All Immigrants.
Yes we are. Every person you have met or will meet is an immigrant. This is not about your parents arriving here from somewhere else, or your grandparents, or even your ancestors going back 10,000 years or more. Every person living or that has lived on this planet (or solar system) is alien to the Milky Way galaxy.
An outrageous statement? Not if you examine closely our origins. The star that we affectionately call Ol Sol was once part of very small galaxy, a diminutive neighbor to the majestic Milky Way. Our Sun, ensconced in that cozy miniature galaxy surrounded by a number of siblings, was just sputtering into existence several billion years ago. What a proud little galaxy it must to have been. Not very well organized. Just a scattering of average sized young stars. But, it had a grand secret – a plan for creating living things. This quaint collection of stars barely able to call itself a galaxy recognized that at least one of its terrestrial charges had a most rare opportunity for producing plants and animals in many forms, leading perhaps to the development of intelligent life.
The Milky Way is big. Not the biggest, but clearly it can be classified as among the big. A galaxy can be called big when it encompasses billions and billions of stars, plus other objects, that stretch many light years across space. (If you want an accurate count, say it has a bigllion stars.) It is known that a galaxy grows from a barely distinguishable knot of stars to a super size by two means. First, it makes new stars, generation after generation. Second, after it has attained a certain total mass, its gravitational attraction begins to act on other galaxies within reach, large and small. The large galaxy entices others nearby, especially the smaller ones, into joining its larger grouping. Most low mass galaxies are unable to resist. As these approach and enter the larger assemblage, they are stripped of their stars. Each star, now just one among a ‘bigllion’, is assigned a nondescript place of orbit within the big galaxy. A galaxy gets to be big by repeating many times this process of absorption of smaller units.
That’s what happened to our progenitor galaxy several billion years ago. While it was still intact it looked over at the dazzling lights of the huge galaxy we call the Milky Way. So organized. So magnificent. So attractive. Great things must be happening there. So irresistible! And, there was this – our home galaxy’s plan for creating Life had hit snag. The basic chemical compounds had been assembled on several of its planets, carbon compounds, even a few amino acids. But, the physical conditions were just not right. For example, the plan called for liquid water. There was plenty of H2O, except that on the various planets it was either hot steam or frozen solid, and almost always mixed with the wrong chemicals. Then there were the missing elements. Our little galaxy had gleaned from space a few precious components during its travels. Still, it lacked certain heavier elements. These could only be produced by super novas (exploding giant stars), rare in a small galaxy. Over in the Milky Way these chemicals were abundant.
Life! Was it worth the loss of independence? Loss of self identity for this small galaxy? Indeed, yes! For it brought into being something very uncommon, perhaps unknown in that much greater galaxy. To complete its mission this toddler of a galaxy had to sacrifice its very self and wholeness. Scientists assume that the spontaneous emergence of living things requires a vast network of opportunities and a high degree of complexity, both available for a long span of time. Not so? Well, our little galaxy and its special star did it in record time. The Milky Way does not deserve credit for this accomplishment. As far as is known, the Milky Way has not produced advanced life forms. Indeed, during its early turbulent times this now colossal galaxy would have snuffed out any attempts at life. Instead of turning our detectors for intelligence onto the giant galaxies, perhaps we should be looking at those small mom and pop galaxies out there, alone in dark space, dreaming big dreams.
You may have noticed the references in this article to our small parent galaxy as ‘it’. It does not have a name because scientists feel ‘it’ has lost all identity as a galaxy. Due to the angle of entry into the Milky Way, our star along with the remnants of that lost galaxy obit the giant Milky Way in a way that takes this motley group of survivors a few light years above the plane of the galaxy and then a few light years below, while shuttling between the Sagittarius Arm and Perseus Arm of the M.W. galaxy. Other captive dwarf galaxies have been given names, e.g., Canis Major and Complex H., Sagittarius and UMajor, and even Boo.
After nearly five billion years we may no longer think of ourselves as immigrants; still, our history endures. Like all new generation families we have little or no recollection of the ‘old country’. Even so, doesn’t that little galaxy that gave us life deserve our appreciation? Come on folks, People of Earth, let’s give that unknown and forgotten galaxy a name. (Examples, Atlantis, or Salvitar, or Maia.)
Send your suggested name for that lost, but not forgotten galaxy to
Ask a Mathematician . . . .
Kopernik2

11. The Physicist says:

@Carefree
The CMB comes from every direction. Rather than indicating the location of the Big Bang, it actually provides evidence that the Big Bang didn’t happen in a particular location, but happened everywhere. There’s a post here that talks about that a bit.
The questions on the site come from folk lucky enough to know us personally or who showed up to the booth at Burning Man, or are sent in by email. Mostly email. The address is near the top of the homepage.

12. Amateur Number Cruncher says:

It’s generally thought that Dark Matter/Dark energy makeup some where around 96% (it does vary a little depending on who you read). From what I understand, which is probably very little, dark matter/energy pervade what we think of as empty space. So, if you were moving through “empty” space at whatever speed then wouldn’t you be moving relative to the dark matter/energy? I realize dark m/e is really hard to perceive, but it is still there right?

13. The Physicist says:

@Number Cruncher
Yup!

14. Wondering Joe says:

Our path through static space can be compared to a type of cosmic “tilt-a-whirl”! So if (just taking into account the rotation and the orbit around the sun of the earth) we are travelling at 65500 mph at high noon and accelerating to 67500 mph at midnight then decelerating back to 65500 mph every 24 hours, why don’t we experience these forces?

15. The Physicist says:

@Wondering Joe
We do! The rotation of the Earth (which accounts for the changes in speed you mention) causes a slight bulge at the equator. However, this centrifugal force just decreases the effective strength of gravity close to the equator by a tiny amount.

16. Shaw says:

@kopernik Dunning-Kruger

17. lee says:

if time is eternal, never stops and infinite travels out forever then how can there be a certain place called HERE, how can anything zone into one area if space is forever then there could not be a certain place to start anything…

18. jamesMauro says:

The speed in which we travel will change over time so any answer given if given in exact mathematically correct answer will change over time. the milky way galaxy when compared to other galaxies is moving at 300km/s or 1,080,000km/hr our sun is moving as well. Its been a while but i believe its moving in a relative opposite direction of the galaxy at some speed significantly less than 130km/s (when compared to other solar systems in our galaxy)which i would have to get the exact figures. if the big bang happened at point zero than we can consider that to be the center just as in the earth than the sun is actually moving slower than 300km/s. than you have to figure the directional path of the earth around the sun for that giving moment. so at one time of the year it will be different than another except depending on the orbit when compared to “center of the universe” it might have the same relative speed on 2 occasions but that is of course highly unlikely, given that the orbit is not a perfect shape but totally plausible.

Finally it is highly doubtful that the earth is heading exactly toward center its most probably at some part circle so you would have to pick a moment in time and relate all answers according to that while still calculating real time speed compared to other galaxies because our galaxy is in fact speeding up over time, this could be achieved using algebra and basic calculus to determine the rate of rate of change in a similar function as the rate of change of speed due to gravity.

19. jamesMauro says:

“This changes slowly over time, and in several thousand years from now it will no longer be the case. Fun fact.”
do you know why its changing over time?
here another fun fact the orbit of the moon is moving about 1 inch away from the earth every year its not exactly the same every year but it can be expressed algerbiarctly and charted. Even though we consider the moon to be very little mass because it orbits the earth it changes the gravitational center of the earth towards the moon which is why there is more tidal waves due to the moon. but in addition the gravitational mass of a set area of space is decreased as the 2 objects take up more space. For example if you had 2 high powered magnets of variant sizes close together and an extremely large magnet far away it would have a certain amount of pull. now if you began to take away the smaller magnet to infinity(magnet completely gone) it would have less pull. our orbit around the sun is not a perfect circle its more like an egg, which further means we are over time due to all causes getting further away from the sun IE 1 earth year is longer this year as it was last. and 1 moon cycle is longer than last years.

however if you look at nasa website they have lunar cycles spread sheet that is completely in accurate they only have the current lunar cycle and kept placing that range back to every known date, if i had there computer processing power i could give an exact answer to what the lunar cycle was during the time of the dinosaurs.

P.S ever hear someone say the moon looks smaller now, its actually true it should and it means they have a good memory a farther object does appear smaller.

20. Dust says:

If it’s January 1 winter in Michigan and I look at the sun could you tell me what direction we are traveling through space from the epicenter of life or if it’s July 4 and it’s morning and I’m looking at the sun same there what direction are we traveling through space true epicenter of life

I have a thought on how fast we are moving through space/time. Assuming light speed is actually a constant. 🙂 Imagine that there are three spaceships, one light year apart, traveling at .5 the speed of light in a straight line. If the middle ship signals the leading ship with a flashlight, the leading ship will not will not see the light for two years. If the middle ship signals the trailing ship, the trailing ship will not see the light for half a year. If this is correct, could we not construct an experiment with our current space crafts to determine our actual speed in the universe by measuring the time it takes light to go “ahead of” and “behind” the earth? I appreciate you thoughts.

22. The Physicist says:

Excellent thought experiment!
But relativity is slippery enough to get past it. Time doesn’t just go slower at (relative) higher speeds, it gets “slanted”. If all three ships travel at the same speed they can sync their clocks. They’re all stationary (relative to each other) and the signals received arrive at the same time.
If you were watching all three pass by the situation plays out exactly as you describe, but while the ships think their clocks all read the same, you see the front ship’s clock running behind the others and the rear ship’s clock running ahead (all at the same rate, and all ticking slower than your clock). Everyone would agree on what the various ships clocks read when the light was sent and received, they’d just disagree on why.

23. Sid says:

Let’s think of a condition; Say a light ray is thrown towards an arbitrary direction, and assume that this light ray faces no obstacles (though it will not be the case) like any object or come in scope of gravity etc., considering this, how far would it travel?

Related to this, if we believe the space is expanding with all the matter (and its anti counterpart) in it, does the space big enough to always contain the light ray considered above. If yes, is the expansion of space itself is faster than light? If no, then where the light ray lands after it crosses whole of the space?

24. Paul S. says:

Would not space be created by the mere fact that light was there, I mean that the lights presence creates space as it travels. Would that mean that space disappears after it passes?

25. James mauro says:

NO, the space in which the light and or other particles have traveled through does not disappear it is still measurable and definable.

26. Kim G says:

Hypothetically; If a person is in a spacecraft motoring along at 30,000 mph. And suddenly all matter was removed from the universe except for the spacecraft the space craft would then not be in motion at all. This is perplexing because the excelleration and deceleration forces could still be felt. Put on the brakes and feel the force that throws you foreword. Push on the gas pedal and feel the backward force. But there is no movement because movement is only relative to another object. This is something that I have pondered since I was about 12 years old. It’s still hard to fathom.

Here is my dilemma; if speed is only relevant when measured against another object, that might mean each object can hypothetically be moving at near the speed of light but in opposite directions. Again, take away all other matter in the universe and eather object could be moving at almost double the speed of light relative to the other because the speed is only measured between the two objects. I believe that I read that Einstein stated that the speed of light could not me exceeded.

27. HarveySom says:

The ball is going so fast that everything else is practically stationary. Even the molecules in the air are stationary. Air molecules vibrate back and forth at a few hundred miles per hour, but the ball is moving through them at 600

28. mark says:

guys if the earth is travelling so fast through space could gravity not be the g force form the earth? the unified spin tied with such fast movement could generate enough G Force to stick everything down, ie gravity!!! its basic aerodynamics no????

forward motion = resistance = energy = gravity

i mean how can gravity be the earth pulling us down, yes matter attracts matter but that still don;t make sense to me

29. Curious says:

Something has bothered me for a long time. If there was a big bang and if the universe is infinite what is everything expanding into?

30. baller says:

If we are traveling at these speeds, why havent the stars alignment /positions changed ? It’s been documented as being the same for thousands of years. Curious please help

31. The Physicist says:

@baller
Most of the stars we see are close by and moving with us at about the same speed, like two leaves on a river. There is some drift, but it happens on long time scales. We can literally look at how fast nearby stars are moving and in what direction and predict the arrangements in the future. In the next fifty thousand years the Alpha Centauri system will twice stop being our closest neighbor as Ross 248 and Gliese 445 pass by.

32. James says:

The Stars positions do change over time, a grouping of stars tends to move like water or a flowing pattern, as if that grouping of stars can be considered one mass, however when all is calculated it is a long time before any notable change will take place, if an object is traveling away from you at x speed you will not see that it is moving with the naked eye, some stars are more notable, the over change in star location compared to the earths relative view takes awhile, and some stars will stay in realitivily the same view for hundreds of thousand of years, while other may have a notable change in 10,000 or even less.

33. Friend says:

Listen folks, don’t be fooled. No one in History has ever measured the speed at which we are supposedly travelling 1000 mph at equator. Let the people who tell you that go beyond the pull of gravity straight up in the sky. Remain there for 10 mins or so then decent straight back down. Surelyrics the landing point would be miles away now from where they originally started. I guarantee you they will be right back where they started or in the proximity

34. NetBlueSky says:

Iv’e heard that the CRB has a pattern and it extends through the known universe. The center of this pattern has a wonderful blue sphere … the earth

Michelson-Morely conducted a credible test of the speed of the earth through space and found it to be essentially zero.

35. David says:

I am wondering if someone could answer this question? If we observe a distant galaxy, A, red shifted and proceeding away from us at almost the speed of light, the we face the opposite direction and observe galaxy, B, red shifted and proceeding away from us at almost the speed of light. The velocity of A relative to B can never exceed the speed of light so how do we reconcile this?

36. NetBlueSky says:

The Special Theory of Relativity relies on C (the speed of light) being a constant.
The General Theory of Relativity requires light is NOT a constant.

The two CANNOT be reconciled as both valid. C, as a constant, presented so many conflicts to observable science that Einstein came up with the General Theory. (which essentially contradicts the Special theory)

Did you know that the Special theory was a response to the Michaelson-Morely experiment that produced scientific evidence that the Earth does not revolve around the Sun. Since Einstein knew (assumed) that the Earth actually does travel around the Earth, he devised the Special Theory and used Lorentz transforms to adjust the empirical data (a fudge factor) to show that Michaelson-Morely was giving a false reading because..!!! THE LENGTH OF THE INTERFEROMETER TUBE IN THE EXPERIMENTAL APPARATUS WAS ALIGNED IN A PARTICULAR DIRECTION ACTUALLY CHANGED LENGTH BECAUSE IT WAS (assumed) THAT IT WAS MOVING AT 66,000 MPH.(the assumed speed of Earth around Sun)

Now, the ONLY “science” that has ever claimed that the size (shape, lengtht,etc) of an object changes with it’s speed is Einstein claiming it does !!! There is ZERO empirical evidence that shows such a bizarre phenomena actually occurs.

There are many cosmological claims that rely on the fact that a scientific instrument changes it’s actual length because it is on the Earth, and therefore moving, and therefore it’s measurements have to be “adjusted” A great example of this is the recent “Gravity Wave” experiment that has supposedly “proved” there are gravity waves. The very core of the experiment relies on the assumption that the great length of the interferometer tube in one direction was altered ever so slightly but the other one at 90 degrees to it, was not altered. The great contradiction is that they simultaneously rely on Special theory to say that the tube changed length, but then claim that gravity waves altered the speed of light as per the General theory. !!!~ You simply can’t have it both ways…Special and General theory contradict each other.

37. NetBlueSky says:

David,
The previous message was a response to your question about Red Shift. Although my response may appear to have nothing to do with your question it actually does.

When Hubble discovered the red shift it gave the appearance that the universe was expanding …now here is the rub…in all directions away from the earth. That fact was a major problem for those who wanted to maintain that the Earth did not hold a special position in the universe. The red shift was evidence that the Earth was the center of the the cosmos. He was adamant that this apparent result could not be presented to reinforce the idea that Earth is at the center.

So your observation is quite astute and points up problems with the whole lot of Copernican Principle and cosmological science. Keep thinking…keep asking questions

38. Werner says:

Looks like our speed, relative to our position in the universe,
can be very fast.
So – for the sake of argument – we travel through the universe at 0.1 x C,
and nothing can move faster than C.
How can we accellerate a particle to 0.999999998 x C in the Large Hadron Collider ?
There must be some part in the LHC, where a particle cannot be accellerated
faster than 0.899999999 x C and in another part, it can move at 1.099999998 x C,
relative to ourselves on planet earth.