|Proof that the speed of light is relative and additive to the speed of the frame of
reference where it is measured.
Don E. Sprague, Copyright 2007, 2008, 2009
Every round trip measurement of the speed of light has been on a moving platform. Therefore, there hasn't
ever been two identical round trip measurement of the speed of light. Nobody can dispute the statement. The
reason is simple. While both points for the round trip are fixed relative to each other, they are moving relative
to the center of the earth and to the sun and to the galaxy and so on.
|The Fundamental Flaw in the theory of relativity
Don Edward Sprague, 08 February, 2010 Copyright
Here is a simple representation of the most important experiment addressing simultaneous events.
M is a person at the midpoint between A and B so he observes simultaneous arrival of light that
simultaneously originated at A and B. m' moved away from the midpoint between A and B so he observes
different arrival times for the same light that simultaneously originated at A and B. To most people, it is
obvious that the person who isn't at the midpoint will see different arrival times of the light. To
Physicists, it means time has no meaning.
In section 9 of the Theory of Relativity, the focus is placed on arrival time instead of origination time of
past events. Everyone knows the origination time isn't based just on arrival time. The theory converts
different arrival times to a representation of the origination times of the past events. We all know the light
traveled different distances. Thus the indications must arrive at different times.
HOWEVER: The theory says the opposite. According to the theory, since the light travels different
distances, it will arrive at different times which means the earlier simultaneous events didn't seem to
originate simultaneously to anybody who isn't at the mid point. Einstein relativity specifies that: since
they do not seem to be simultaneous events, they are not simultaneous events.
This is a thought experiment described in section 9 of the theory of relativity. The false perception is used
to change the definition of simultaneous and eliminate the meaning of time. The person's movement is
specified to get the person away from the mid point. Then the person's movement is discarded. His
known false perception is converted to fact. That means, section 9 of the theory of relativity says, you
don't need to actually be correct to be correct. You only need to think you are correct to be correct.
I found that nobody disputes the pivotal importance of section IX The Relativity of Simultaneity in the
Theory of Relativity. Section 9 is a very short easy to read section of Albert’s paper and it basically fits on
one 8 by 10 page using normal print and spacing. Section 9 is the linchpin section. Without section 9, the
theory of relativity is meaningless. Shortly I will provide two links to two different places showing section 9
of Albert’s work.
From here on, it is just commentary.
Regardless of your field of interest or skills, you can easily read and understand section 9 of Albert’s paper
if you actually passed the 8th grade. It is very important to have an open mind when reading section 9 of
Albert’s paper. Please don’t go in thinking is it either true or false. Go in thinking the facts must support
the conclusion. Then form your own conclusion.
I have discusses the theory of relativity with a large number of people including Physicists. Everyone
consistently works to move the discussion away from section 9 of Albert’s paper. Very few people attempt
to explain the justification for the conclusion of section 9. Most people try to justify section 9 with other
sections of the paper. That is, they say that section 9 is correct because the other sections are correct.
Then they justify the accuracy of the other sections because section 9 is correct. That is; A is correct
because B is correct; and B correct because A is correct. Occasionally people have said they understand
the theory but they haven’t read it because they don’t have time. They say they haven’t even read just
the short section 9 portion while they argue the validity of that section and the entire paper. NOTE:
When discussing this thought experiment, people will try to move away from the problem. Don't let
people divert unless or until they address the known false perception used to replace fact. Once the
discussion moves away, they have successfully diverted from the problem they can't answer.
Basically; section 9 is about a THOUGHT experiment. That means, the pivotal section of the theory isn’t
based on actual experimental data. It is simply based on a philosophical thought experiment conclusion
that requires information to be both known and intentionally ignored. Section 9 deals with a hypothetical
person on a train. Just as the hypothetical person on the moving train is at the midpoint between
simultaneous events A and B on the embankment, we tell him two events just happen. He doesn’t know
he is moving. Eventually the lights arrive at different times.
The typical explanation says he has two options.
1) the trigger events happened at different times so they aren’t simultaneous.
2) the trigger events happened at the same time but the light traveled at different speeds.
Since C is constant, the only choice is option 1.
However; as always, I come in and say it is a trick question. There is a third option.
3) The light events happened at the same time. Light travels at the same speed from both points. Thus,
the person on the train is moving. Nobody addresses the issue that the hypothetical train passenger in
the thought experiment would say the events are simultaneous when he knows the facts. The use of the
term trick question is important to help people have a clear mind when reading section 9 of Albert’s
- Here is another trick question for old timers. How many groves are on one side of a 33 1/3 RPM record
that last 2 minutes. Before going to any formula, think about the grove on a record. It is one grove that
goes around and around.
- If a game baseball game is called after 5 innings because of rain, how many outs were there? Many
people will go to the formula 3 times 5 = 15. Actually it is 6 outs per inning (3 each side) making it 30 outs
after 5 innings.
- One of my favorites is: If a bear walks past a house with all 4 sides facing south, what color is the bear?
To determine the color of the bear, you must first determine the location of the house. I told you where
the house is located.
- My very most favorite trick question. When indications of simultaneous events don’t arrive at a person at
the same time, what does it mean? To most people it means the person isn’t at the mid point between
the events. To a Physicists, it means time has no meaning.
Before reading the short section of Albert’s paper, you might find the short video of value. It shows how
the first person determined the size of the earth based on shadows and sticks.
Now, please go to one of the two following links to read just section: IX. The Relativity of Simultaneity from: Albert
Einstein (1879–1955). Relativity: The Special and General Theory. 1920.
http://www.bartleby.com/173/9.html or http://www.ibiblio.org/ebooks/Einste...Relativity.pdf
The first link goes direct to section 9 of Albert’s paper. The second link goes to Albert’s complete paper. Page through
using the up and down arrow next to the page numbers on the control bar.
After you read section 9, The Relativity of Simultaneity, then you might be ready for some questions.
- For section 9 to be valid, is it necessary for the train to be moving? Yes is the only answer.
- For the hypothetical train passenger to think the events aren’t simultaneous, can he be aware of all the
facts? That is; can he be aware that the train is moving. No is the only answer. If he knows he is
moving, then he would be able to determine a reason for the different arrival times of the simultaneous
- Based on the above, is it remotely possible that the simultaneous events are simultaneous since the
hypothetical train passenger in the philosophical thought experiment was specifically required to be
mistaken as a result of a lack of experience and knowledge? Yes, it is possible. It is more than possible.
It is the only choice.
SECTION 9 Examined in detail.
We have the embankment. The train is miles away and won’t go past the embankment for sometime.
A------------------------M-------S1-------S2--------B > this is the embankment at velocity 0
>>>>>>>>>>>>>>>A1>>>>A2>>>>A3>>>>>> Light from lightning strike at point A
<<<<<<<<<<<<<<<B3<<<<<B2<<<<B1<<<<< Light from lightning strike at point B
On the embankment we have the two simultaneous events at A and B. We have the M for the man at
the Mid point between A and B. We have two sisters on the embankment. The sisters are so much alike
they look like twins, so we will call them twin sister 1 and sister 2. I suppose the man and the twin sisters
don’t get along because they are standing apart. Shortly after the simultaneous events happen at A and
B, some light from B arrives at Sister 2. That is because she is closer to B. Then the light from B arrives at
Sister 1. Then the light from A and B arrive at the man at the Mid point between A and B. Then the light
from A arrives at Sister 1. Then the light from A arrives at sister 2. All this is as expected. The sisters aren’
t at the mid point so the lights arrive at different times. I can’t see how anybody could dispute the
scenario. In fact; in all my discussion, nobody challenges these results. Nobody claims the simultaneous
events aren’t simultaneous because the sisters, who aren’t at the midpoint, don’t observe them as
The train approaches. Get ready. Now, the train points A and A’ are aligned. Points B and B’ along with M
and M’ are aligned. Even though A/A’ and B/B’ and M/M’ are in different frames, they are comparable
locations across frames. Their movement doesn’t distinguish them.
A----------------------------M-------S1-------S2--------B > this is the embankment at velocity 0
A’--------------------------M’S3--------------------------B’ > this is the train at velocity V
----------- A’--------------------------M’S3--------------------------B’ > train at velocity V
------------------- A’--------------------------M’S3--------------------------B’ > train at velocity V
The man on the train is traveling with sister 3. She is so much like sisters 1 and 2 that they must be
triplets. They are riding on a very modern train and don’t know they are moving. They don’t feel the
bumping and don’t hear any noise. They must have been distracted and weren’t aware that the train left
the station sometime ago.
The lightning strikes A and B and A’ and B’ at the same time. For relativity to apply, we must have 4 light
events instead of just 2. Although we go through just addressing the two lightning strikes on the
embankment, the exact reverse applies. After the lightning strikes A and B, the train moves. Just as
triplet sister 3 is aligned with triplet sister 1, that is the time that both sisters and the man at the midpoint
on the train at observe the light from point B.
Remember earlier we said: Even though M and M’ are different, they are comparable locations across
frames. Their movement doesn’t distinguish them. The same applies to the triplet sisters. Even though
S1 and S2 are different from S3, when they are aligned, they represent comparable locations across
frames. Their movement doesn’t distinguish them.
Some time later, both lights simultaneously arrive at the man on the embankment. Just as triplet sister 3
is aligned with triplet sister 2, that is the time that both sisters and the man at the midpoint on the train
at observe the light from point A.
Thus we have three comparable cross frame locations.
M and M’ are cross frame comparable locations. Even though M and M’ are different, when they are
aligned, they represent comparable locations across frames. Their movement doesn’t distinguish them.
Sister 3 and 1 alignments are cross frame comparable locations. Even though sister 3 and sister 1 are
different, when they are aligned, they represent comparable locations across frames. Their movement
doesn’t distinguish them.
Sister 3 and 2 alignments are cross frame comparable locations. Even though sister 3 and sister 2 are
different, when they are aligned, they represent comparable locations across frames. Their movement
doesn’t distinguish them.
Are you seeing the trend here. It is perfectly correct for Sister 1 and Sister 2 to understand that the
arrival times are different for lights from A and B. Since we established that the points where sister 3
aligned with sister 1 is comparable, and, where sister 3 and sister 2 aligned is comparable, then sister 3
understand the reason the lights from events that happened at points A and B are simultaneous even
though they arrived her locations at different times. So we have a disconnect. The Physicists on the train
needs to listen to the three women instead of listening to Albert who is standing on the embankment
watching the world go by.
Section 9, The Relativity of Simultaneity is the pivotal section of Albert’s work. It is based on a carefully
specified condition that must deliver a false illusion. The person on the train must be moving but can’t be
aware of the movement. This is required to facilitate the mistaken conclusion that the cross frame
simultaneous events changed from simultaneous to not being simultaneous. Without the specified error,
time retains meaning. With time having meaning, the entire paper goes away.
Many very brilliant well informed people have written excellent papers about relativity. Most do a
wonderful job of explaining the conclusions of the theory based on the assumption that section 9 is
correct. Most but not all Physicists accept Albert’s paper as correct. Even though they do, I still haven’t
found any to address my challenge to section 9.
Paul Marmet, Ph. D. (1932-2005) was a brilliant Physicists. He had a brilliant career and worked in many
areas. http://www.newtonphysics.on.ca/info/author.html He wrote many papers. Some of his work also
challenged the theory of relativity. His approach was different than mine. In the about 100 years of the
theory of relativity, many brilliant Physicists didn’t accept it from the first day it was published until it was
accepted many years later. Since it was accepted, many brilliant Physicists like Paul Marmet, Ph.D.
continued to challenge it. I simply took a different tact to challenge the theory. I examined the theory and
found the pivotal section that is based on an illusion becoming fact.
I am looking forward to the day when someone will give a valid explanation for a specified false
perception to replace fact, or; for the acknowledgment that facts can’t be replaced by a specified false
perception. After that day, I can move on to other things with either finally having a better understanding
of the concept that logic doesn’t apply in physics; or, Physicists can move on to bigger and better work
dealing with things moving through time and space instead of thinking that time and space bend to fit
Addendum: Do physicists have open minds?
My concern is to improve science. In one discussion I was pointed to very good paper that goes into
detail explanations about the conclusion of the theory. Regardless of the section 9 problem, the paper is
very good work.
In that paper I found;
New experiments are being performed every day, and new explanations are being devised every day.
Perhaps someday a reliable experiment inconsistent with relativity will be performed. When that day
arrives scientists are prepared to abandon relativity, just as Einstein was prepared to in 1921
However, relativity is far more likely to be modified than completely overturned.
I hope that is the case. I found substantial examples of the results of the theory. I didn’t find anything
that addresses the section 9 problem. I doubt it will be replaced with another form of relativity. I suspect
some form of proximity factors that include very inclusive consideration of complete data beyond things
like Doppler on a super scale. That is for the experts in many areas to address.
Addendum: All frames aren't equal.
The earth and a train aren't equal. Two trains are equal. When the Albert says the train and
embankment are interchangeable, that isn't correct. It is obvious that the train can't be considered to be
interchangeable with the earth. So what conditions allow the interchangeability of two frames?
The origination events must have the same relationship with both frames for the frames to be
interchangeable. There must be comparable conditions. Two lightning strikes in one frame don't translate
to the other frame.
To be interchangeable,
- there must be 4 simultaneous light origination events, 2 in each frame. Or,
- points A and A' must be truly the same. Or,
- they must be isolated from either frame.
None of this alters the original problem. The arrival time doesn't determine the origination time.
Addendum: All light measurements relative to ground, none relative to other frame.
To review experiments addressing the theory of relativity, mostly the speed of light,
When reviewing that site, I realized we have an assumption I had missed before. As far as I can determine, all
experimental data measuring the speed of light has basically been done relative to the earth. That is; I can’t find any
experimental data relative to the train in Albert’s thought experiment. Thus; we accept without proof that light is going
C inside the train. It seems that we only know that every experiment shows it constant relative to earth. A comment
that the sprague light race won’t work prompted me to think of the above issue. We have all said the speed of light is
C relative to the train. If that is so, then light from a flashlight on the train is going C if the flashlight is held both
inside and outside the train window. Suppose the speed of light isn’t C relative to the train. Suppose it is bound within
it’s relativity to the earth.
I searched and can’t find any true moving frame experiment measuring the speed of light other than those where the
earth is the moving frame. Has the MM experiment or any comparable measurement been done on a train or in an
airplane or on a spacecraft? Each adds variables. Perhaps the spacecraft or a high flying airplane moves it too far from
the proximity relationship with the earth. Please don’t focus on the other variables. Please focus on the search for
proof that the speed of light is C relative to another cross earth frame such as the train.
Copyright All rights reserved.
|100% accurate universal time clocks
Thinking about how to making 2 or more 100% accurate synchronized universal time clocks could benefit
from thinking outside the box while looking for something new out of something old. Literally, when we
think of a clock, we think inside the clock box for a movement to monitor. A very old way of looking for
constant or predictable movement is to look at the stars. With modern technology, and data collection and
sharing methods, we can observer various stellar events from the past to project future conditions. One
stellar clock program and data set can be loaded into 2 or more stellar clocks with cameras and update
connections between all devices. The dynamically updated programs and data allows all the stellar clocks to
accurately calculate and display the common device time and positions of the clocks regardless of their land
or space based position within their known stellar data array.
The data consists of historical star maps with position and transition activity. It also tracks the positions of
other stellar clocks. The programs calculate the projected position and conditions of various stars or devices
any specified time. The update links between the devices allow dynamic data and time synchronization
confirmation among devices.
This tool delivers one common ubiquitous time that progresses or builds upon it’s self at a constant rate.
This is an updated description of processes defined in 2007 Copyright material.
Copyright 2007 2008 2009 2010 Don Edward Sprague. All rights reserved.
The Classical laws Of Physics are “considered to be wrong or incomplete”. Since our knowledge of forces
and conditions is incomplete we have Einstein’s Laws to replace Classical Laws. We know Einstein relativity
has a fundamental flaw that results in a mathematical impossibility with time stopping and gravity going to
infinity. Thus an examination of the Laws of Physics is on order.
It is widely accepted that Einstein specifies that the laws of physics are the same everywhere and the
speed of light is the same everywhere. Actually that isn’t what Einstein says. His paper says:
The speed of light is the same for all observers, no matter what their relative speeds.
The laws of physics are the same in any inertial (that is, non-accelerated) frame of reference. This means
that the laws of physics observed by a hypothetical observer traveling with a relativistic particle must be the
same as those observed by an observer who is stationary in the laboratory.
Einstein say: A curvature of rays of light can only take place when the velocity of propagation of light varies with
position. Now we might think that as a consequence of this, the special theory of relativity and with it the whole
theory of relativity would be laid in the dust. But in reality this is not the case. We can only conclude that the
special theory of relativity cannot claim an unlimited domain of validity; its results hold only so long as
we are able to disregard the influences of gravitational fields on the phenomena (e.g. of light).
The impact of disregard of influences:
A limited Domain of Applicability is established through exclusion of known information. Inclusion of known
information expands the Domain of Applicability but invalidates any theory that requires information to be
- Conclusions from experiments must not exclude relevant information.
- A statement may seem to be basically accurate when specifically limited to omit data.
- Consideration of a statement must address the implicit as well as the explicit.
Galileo’s, Einstein’s and Classical relativity laws of motion:
Perhaps Galileo’s Law is incomplete or misunderstood. Thus, the need to clarify or expand to be inclusive.
A comparison of the Classical, Einstein and enhanced Classical relativity laws gives:
- Galileo’s law: All speeds are relative to the speed of the observer.
- Einstein’s law: All speeds except space and time are relative to the frame of reference.
- Classical relativity law: All objects are moving and all velocity of observable objects can be measured
relative to the velocity and perspective of any number of observers in various locations and the results from
observer to observer must correlate. Note: this law includes light, space, and time.
My enhanced specifications are inclusive for an unlimited Domain of Applicability:
In an inclusive Classical hierarchy of Relativity (ChR),
- The Laws of physics are the same everywhere under all conditions. There is no get out of the laws free
card. The laws of physics are the same everywhere regardless of the movement of the frame of reference.
- There is no such thing as a stationary object. Nothing remains at rest at a point in space at any time from
moment to moment. There is such a thing as one thing being basically stationary relative to another object.
Thus, ChR says no speed is absolute. Speeds are relative to frames in a hierarchy.
- An observer inside a box has endless xyz coordinate that aren’t obstructed by a wall or lack of direct
visibility. However; a frame’s xyx coordinates have internal boundaries. A flipped coin inside a car moves as
compared to the car. A flipped coin on earth outside the car moves as compared to the earth. It is visible to
the car observer and the earth observer. The coin motion in the car is directly compared to the car and
indirectly or additively compared to the earth.
- When we observe any event, we are watching the results of what happened sometime ago.
- The movement of objects have both a direct as well as an indirect relationship or impact on the movement
- The movement of objects in time and space can be consistently measures and accurately predicted
because time and space are constant.
- All the variables must be included to accurately project the outcome. Size, movement and structure of one
or more objects are variables that impact the universal magnetic field and other objects will be impacted by
- As any disturbance in the universal magnetic field originates, travels and impacts a target, there is an
equal and opposite reaction throughout the path.
- Time is NOT relative to a place, object or event. All things exist at moments in time relative to all other
objects. Events that happen at the same time in any frame are simultaneous regardless of frame of
- Any movement of any objects in time relative to any movement of any other objects in time does not
change time or space, it merely changes the location or relationship of the objects to any point of reference
at a prior time.
- The effect of acceleration may simulate the effect of gravity, the cause of each is very different. Similarity of
effect does not necessarily result in similarity of cause. Acceleration is not the same as gravity. It may
temporarily be confused with gravity for the inexperienced observer.
- Optical illusions will or may cause distant or moving objects to seem to be different.
- When an object’s state of rest or motion is changed in relation to a hierarchy of relative, it may or will
deflect to some extent during the transition time.
- Identical object at rest relative to or sitting on other moving object will typically remain identical.
- Transition deflection occurs when changing the speed of moving objects and the deflection will vary among
objects and may remain or reverse when transition is completed.
- Deflection of measuring devices will deliver false data resulting in false conclusions.
- Selection of a body of reference must include consideration of the hierarchy of relativity. Space and time do
not change. The locations of various objects change in time and space.
- Speed of objects are additive within their classical hierarchy of relativity
- The Speed of light is additive to the movement of the frame of reference where it is emitted and where it's
speed is measured.
- An electromagnet produces a field that is similar to gravity. Gravity does exist.
- Gravity will cause the direction of travel of Light energy to bend.
- Lighter objects moving in space do not simply roll down hill to heavy objects moving in space.
- Energy dissipates as it travels.
- Light energy dissipates.
- The dissipation of energy and light energy can be measured.
- There is proof of a dynamic changing universe. That doesn’t mean the universe expands.
- The speed of light is relative to all observers, no matter what their relative speeds.
All frames equally applies to the laws of physics being the same in all frames. It also applies to the speed of
light being the same in all frames.
- The choice of frames doesn’t alter the conditions of events in any other frame. Thus; all frames are equally
valid in that the laws of physics and conditions of events are the same in all frames and all observers in all
frames might be equally able to gather the same data from the different observational frame or vantage
- A choice of equally valid frames of reference doesn’t change the laws of physics or actual conditions. A
choice of frames DOES alter the ability to observe. A person on earth can’t observer the far side of the
moon. The choice of frames doesn’t change the distance between points or the time to travel between
- The choice of frames doesn’t change the distance between points or the time to travel between points in
the frame where the points are tied to. An inch in one frame is an inch in any frame. A second in any frame
is a second in any frame.
- The motion of an object isn’t changed just because it is observed from different frames.
This may be the biggest area of discussion.
Falling ball with sideways moving platform:
Consider one of the oldest examples of demonstrating relative motion. This demonstration uses one ball, 2
video cameras and one moving platform. The platform moves sideways at a constant velocity. One camera is
attached to the platform while the other video camera is situated on the floor. Both cameras are continually
operating and showing their images side by side on one or more screens.
The platform is moving and the ball is released from a perch. The display from the camera on the platform
shows the ball fall straight down. The display from the camera on the floor shows the ball fall in a curve
line. Both videos show the real, correct motion of the ball. An observer looking at the video screen can only
determine that one image is of a ball falling straight down and other image is of a ball falling in a curved
Informed variation demonstration.
In my variation, tools are used to gather information. Lines are marked on a background glass behind the
falling ball. The marks show a top point mark A, a bottom mark B, a straight line between marks A and B.
The line between the marks has standard ruler marks showing the length of the line between marks A and
B. Velocity meters and event timers are situated on the moving platform. Additional velocity meters and
event timers are situated on the floor. The event timers record the time the ball arrives at marks A and B.
The velocity meters show the velocity of the ball. The platform camera shows the complete viewing area
including the perch where the ball is situated before it is released, and the mechanism that triggers the
release of the ball. The glass background allows the viewers to see a mirror on the wall behind the setup.
The Mirror has length marks. The reflected image shows the complete setup including the both cameras.
The floor camera shows the complete view of the platform with the camera, the ball perch, the marks on the
background glass, the wall mirror, the wheels the platform rides on, measurement marks on the floor and
back wall mirror showing the distance the platform moves, the motor and gears driving the platform and
the meter showing the velocity of the platform and so on. The Computer analysis of both screens is
performed to measure the events times of the ball arrival at marks A and B as viewed by both cameras.
In the standard demonstration, lack of information prevents an informed conclusion. The second
demonstration with the marks and measurements and the velocity meter and the mirrors and the motor and
the gears and so on, the video observer can make an informed conclusion. Observers can see the split
screen and the data to see the ball velocity as considered from both vantages. Both side images and data
show the ball velocity, travel time and travel distance as compared the platform is the same as viewed by
both cameras. Likewise, the ball velocity, travel time and travel distance compared to the floor is the same
as viewed by both cameras.
Alternative suspended in air ball demonstration:
I provide another demonstration that also uses one ball, 2 video cameras and one moving platform. The
platform moves up in this demonstration instead of sideways as in the other demonstration. One camera is
attached to the platform while the other video camera is situated on the floor. Both cameras are continually
operating and showing their images side by side on one or more screens. Both record the activity from 1
hour before the demonstration to 1 hour after the second demonstration.
In the first demonstration, the background information is hidden. One side of the video shows a falling ball.
The other side shows magic ball that is suspended on air with a platform that moves up the ball. In the
second demonstration, the complete information as above is included in the side by side video images. The
first demonstration doesn’t allow an informed decision. The second demonstration allows all observers to
know the ball is falling.
In the sideways moving ball, the Lorentz contraction supposedly has a ball that is the simultaneously the
same height but different width in both videos. In the suspended in air demonstration, the Lorentz
contraction supposedly simultaneously has the ball different heights but the same width in the different
videos. The supposed difference is as a result of the math induced error from using frame independent light
speed with relative time.
This demonstration shows that the observation of the motion is frame dependent. The laws of physics don’t
change from frame to frame. Both frames are equally valid for consideration of the laws of physics. The
distance the between mark A to mark B on the backboard is the same regardless of viewer. The length of
time the ball falls from mark A to mark B is the same regardless of viewer. The velocity the ball falls from
mark A to mark B is the same regardless of viewer. The distance and velocity from observed moving point A
when the ball is released to moving point B where the ball arrived is greater than the distance and velocity
from the A and B marks on the backboard.
Observers viewing from the moving camera and from the stationary camera use the one and only same
laws of physics. Both can determine the distance between mark A and B on the moving platform. Both
observers can calculate the distance mark A and B moved between the time the ball was released and
when it arrived at mark B.
There isn’t a preferential frame for the laws of physics. There is a preferential frame for considering the
motion among moving bodies.
As I have said all along and as is now in wiki:
A change in the choice of this coordinate system does not change an observer's state of motion, and so
does not entail a change in the observer's observational frame of reference. This viewpoint can be found
elsewhere as well. Which is not to dispute that some coordinate systems may be a better choice for some
observations than are others.
Review the last line: some coordinate systems may be a better choice for some observations than are
- The operative included words are: better choice for some observations,
- The choice for observations doesn’t alter the laws of physics. There is NOT a preferential frame for the
laws of physics.
The laws of physics being the same in a frame doesn’t mean all frame are unconditionally the same without
respect to the laws of physics. All frame aren’t equal but the laws of physics apply equally in all frames. A
train and a car and the earth and the sun are all different but the laws of physics are the same in all of
Thus, the laws of physics are unconditionally the same in and across all frames at all times. All frames aren’t
equally valid as being the same size, shape, mass, color and have the same motion. Different conditions in
and across frames doesn’t make the laws different.
This is a synopsis from my 2007 papers.
Copyright 2007 2010 Don Edward Sprague. All rights reserved.
|Sprague demonstration of Galilean transformation vs Lorentz Transformation.
Copyright Don Edward Sprague
I show two primary variations of the demonstration. In version one we use a ruler, paper and
a marker. In version 2 we use 2 markers and paper.
Version 1, paper ruler and marker
1 - Attach markers on a rules:
- Attach one marker at the 1 inch mark on the ruler,
- Attach one marker at the 2 inch mark on the ruler,
- Attach one marker at the 3 inch mark on the ruler,
2 - Place the ruler on the top left part of the paper so the markers make marks on the paper.
3 - Move the ruler with the markers diagonally down and along the paper so there are 3
diagonal marks on the paper from the left top to the middle bottom.
4 - Hold the ruler while moving the paper to form 3 diagonal lines from the middle bottom of
the paper to the top right of the paper.
5 - You have three V shape marks on the paper.
- The left side of the V shape is with the moving ruler frame,
- The right side of the V shape is the moving paper frame.
6 - Measure the distance between the marks to find the Lorentz Contraction.
You can’t find any contraction with either frame moving.
In the first case, you have the RULER move. In the second case, you have the PAPER move.
In both cases, there was a frame that was considered to be stationary and a frame that was
considered to be moving. You can’t find the Lorentz contraction in either results. You do find
Classical Mechanics and the Galilean transformation are accurate in both results.
Version 2, paper and markers.
1 - Place the paper on a flat surface.
2 - Align both markers to be as though they are one marker with two points to mark on the
If you hold the markers in one hand and move them sideways, you will have two parallel lines
3 - Hold both makers and move the MARKERS to form a large double V on the paper.
4 - Turn the paper over.
5 - Hold both makers and move the PAPER to form a large double V on the paper.
In the first case, you have the MARKERS move. In the second case, you have the PAPER
move. In both cases, there was a frame that was considered to be stationary and a frame that
was considered to be moving. You can’t find the Lorentz contraction in either results. You do
find Classical Mechanics and the Galilean transformation are accurate in both results.
You can’t find a Lorentz Contraction in either demonstration.
In the Galilean Transformation, time, distance, and speed is constant within frames with speed
additive across frames.
In the Lorentz Transformation contraction, time, distance and speed is constant within frame
with time and distance variable across frames.
You can’t find a Lorentz contraction in either demonstration.
|Which object is moving in deep space?
31, Jan 2011, Copyright Don Edward Sprague
Consider imaginary things in deep space without capability to see other stuff. Since they are so isolated,
there is no motive to gain information. The discussion is basically meaningless. Let’s give motive. On one
thing, there is some food. On the other is a hungry person. The hungry person has all sorts of tools but
no food. If there were just a way to get the food from the other thing. Now there is a goal and motive to
determine the motion. The person can use methods that are used on a pool table. The person can propel
an object to cause the food to be knocked off the other thing in such a way that it is propelled to the
person planet. The single motion of one or the other requires different trajectory of initial propelled object
to cause the desired trajectory of the food. Compound motion of both things requires another trajectory.
It takes testing experience to eventually arrive at the correct actions to get the food.
Copyright Don E. Sprague 2011 All rights reserved.
|Slowing of Pioneer 10 solved. It seems that the speed of two probes slows by about 6 mph per century.
The science community claims the slowing of Pioneer 10 is explained by the electric universe. Then they go
on to state that they don’t know how it all works. While Classical hierarchy Relativity does explain the
electric universe, the electric force is not the cause the slowing of the craft.
The cause of the slowing of the space craft in distant empty space is the fact that the empty space isn’t
empty. There is thin stuff out there. The stuff causes drag or resistance. The density of the stuff in quasi
empty space can be calculated based on the surface and speed of the space craft. The stuff that causes
Pioneer 10 to slow is some of the same stuff that causes Interstellar reddening.
Some might call it missing matter. It isn’t missing, it has just been ignored. The slowing of the space craft
makes it harder to ignore the reality of the thin stuff in space.
A Mystery Solved - Welcome to the Electric Universe!
Researchers say Pioneer 10, which took the first close-up pictures of Jupiter before leaving our solar system in 1983, is being pulled back to the sun by an unknown
force. The effect shows no sign of getting weaker as the spacecraft travels deeper into space, and scientists are considering the possibility that the probe has revealed
a new force of nature. Dr Philip Laing, a member of the research team tracking the craft, said: “We have examined every mechanism and theory we can think of and
so far nothing works.”
Research to be published shortly in The Physical Review, a leading physics journal, will show that the speed of the two probes is being changed by about 6 mph per
century - a barely-perceptible effect about 10 billion times weaker than gravity. Scientists initially suspected that gas escaping from tiny rocket motors aboard the
probes, or heat leaking from their nuclear power plants might be responsible. Both have now been ruled out. The team says no current theories explain why the force
stays constant: all the most plausible forces, from gravity to the effect of solar radiation, decrease rapidly with distance.
Empty space that isn’t empty places a constant drag or slowing of the space craft. If the craft direction
were to change or reverse, the empty space that isn’t empty drag would cause the same slowing in
Copyright Don E. Sprague, 01, June, 2011
- Einstein Train thought experiment.
Einstein vs the most significant aspect of the CERN OPERA experiment is the rigor.
- Very accurate determination of location and time of the event was attempted.
- Very accurate determination of location and time of observation was attempted.
For Einstein’s train thought experiment,
- Event time and location determination is was specifically prohibited.
- A person’s eyes detect just the observation time of difference events
— that occurred at some unknown time
— that occurred at some unknown location.
- The difference in arrival time would be less than a second
— with a train going thousands of miles per hour
— with the lights within visual distance.
Even with the OPERA rigor, the data doesn’t match prior experiments sending neutrinos through earth.
The OPERA error with rigor is small compared to Einstein’s significant error from specifically prohibiting
rigor and use of known data.
The OPERA experiment was repeated over 3 years. Extremely accurate measurements were made. Precise
location of the emitter and receiver was measured and checked and plotted. Precise synchronization of the
emitter location clock and receiver clock was repeatedly performed. They do not use Einstein
synchronization of moving a clock slowly or reflecting light once between mirrors. They do not follow
Einstein's statement: “We assume that this definition of synchronism is free from contradictions, and
possible for any number of points; and that the following [that is (b2)–(b3)] relations are universally valid”.
Constant time and constant space or distance tools were used to measure random occurring events at
moving locations. The entire experimental field motion is carefully addressed.
Einstein specifies the TRAIN is moving but the train passenger considers it to a motionless TRAIN frame
regardless of the real TRAIN motion.
The experiment is similar to Michelson–Morley experiment in that the experiment was conducted throughout
the day and year. That compares to the MM rotating table. The speed of the neutrinos remained constant
within a range as compared to the earth regardless of the direction of earth’s almost uniform or constant
travel. This shows that the neutrino speed is almost constant in the almost constant conditions of the almost
constant frame where it is measured. The work is being done in a frame with compound motion as in
classical hierarchy relativity. It is not a static or inertial frame experiment as in Einstein relativity.
Using the OPERA precision, we need to repeat the Einstein train thought experiment in section 9 of his
paper. Oh yes, that is what I have been suggesting for years. Einstein claims time is relative because the
train passenger does NOT know the train moved between the light. With the precision of OPERA, the train
passenger will knows he is on a moving train. Or, the OPERA results could be explained using Einstein
techniques. When Einstein can not explain an event time or location, he simply reverse engineers a formula
and value of variable time and space to account for measured event conditions.
Without conducting a repeat of the train imaginary experiment, we know that Einstein time varies to a
singularity fundamental flaw. The flaw begins with section 9 where he claims that an uninformed person,
who doesn’t use rigor in experiments, is correct because he thinks he is correct. He doesn’t know the
distance to the lights. He doesn’t know the event time. He doesn’t know something as basic as the train is
moving. He only knows the light arrive at different times
Einstein specifically requires that the train motion is NOT considered by the observer on the train. Einstein
claims the train passenger doesn’t know the train is moving so it isn't moving. Then, he uses that first
mistake to claim that the distance between emitter and observer doesn’t change between event time and
Einstein claims the observation time dictates or alters the event time and location.
In a repeat of Einstein's train experiment and in the OPERA experiment, the event time and location is
known by all observers. In both experiments, the arrival time and location doesn't alter the event time
Einstein explained why an illusion looks to be other than reality. We know that a fan blade seems to
disappear with speed. We know that a strobe light makes the moving fan blade seem to magically stop
moving. A rotating disk with black and white lines from the center seems to be a gray disk. A strobe light
reveals that the disk is black and white lines.
Einstein is known to have a fundamental flaw that ends in a singularity. The end point is connected through
a path back to the beginning point which is section 9 of his paper. The train thought experiment is simply an
explanation of an illusion. It is not an explanation of variable time.
Section 9 is wrong. Time is constant. Section 20 is wrong. Gravity and acceleration are different. The
illusion in 9 and 20 are simply illusions. The conduct of the CERN OPERA experiment is only possible through
the use of constant space and time with motion of light speed being relative to the frame or field such as
Copyright 24 Sep 2011 Updated 02 Oct 2011
|Eddington and other eclipse photos and calculations prove ChR refraction.
Refraction is the change in direction of a wave due to a change in it's speed when the wave passes from
one medium to another at any angle other than 90° or 0°.
- When in outer space, light travels “c” as compared to the outer space medium.
- When in a planet or sun gravitational field, light travels “c” as compared to a planet or sun medium.
When light leaves outer space and enters a planet or sun gravitational field, it changes direction due to
changing speed as it moved from the outer space medium to the sun or planet medium. It changes again
as it leaves the sun or planet medium and enters the space medium.
A gravitational lens is a type of lens that refracts light as it changes speed when it moves from being “c”
compared to outer space to be moving “c” compared to inner space. The lens edge or boundary between
outer space to inner space is the same lenses boundary that applies to any theory of gravitational lens and
orbital object that is either pulled back into or escapes the gravity field.
That is as specified in Classical hierarchy Relativity.
All the eclipse photos and calculations show the refraction of light due to the change in direction of light as it
changes speed as a result of passing from the outer space medium and goes through the sun’s
gravitational medium. Space and time do not bend. Light is just refracted.
There it is. Proof of ChR using Eddington and other eclipse photos and calculations.
Copyright. Don E. Sprague 2007 edited 13 oct 2011
The galaxies we see in all directions are moving away from the Earth, as evidenced by their red shifts. Hubble's law
describes this expansion.
Hubble and others observed a correlation between dim stars and red shift. Some redshift shows motion
from the observer. They decided that other reasons for redshift do not apply, so redshift must be showing
the expansion of the universe.
Hubble's law is a statement of a direct correlation between the distance to a galaxy and its recessional velocity as
determined by the red shift.
There it is. It is worth repeating:
Hubble's law is a statement of a direct correlation between the distance to a galaxy and its recessional
velocity as determined by the red shift.
The Hubble constant H is one of the most important numbers in cosmology because it may be used to estimate the size
and age of the Universe. It indicates the rate at which the universe is expanding. Although [B]the Hubble "constant" is not
really constant [/B]because it changes with time (and therefore should probably more properly be called the "Hubble
The Hubble constant H is one of the most important numbers in cosmology:
- it is not constant because it changes with time
- it is properly be called the "Hubble parameter"
The most important CONSTANT numbers in cosmology:
- may be used to estimate the size and age of the Universe.
- indicates the rate at which the universe is expanding.
- is NOT CONSTANT
- is based on redshift that is actually interstellar reddening.
In 1929, Edwin Hubble announced that almost all galaxies appeared to be moving away from us. This phenomenon was
observed as a redshift of a galaxy's spectrum. This redshift appeared to have a larger displacement for faint, presumably
further, galaxies. Hence, the farther a galaxy, the faster it is receding from Earth.
Redshift appeared to have a larger displacement for faint, presumably further, galaxies. Hence, the farther a
galaxy, the faster it is SUPPOSEDLY receding from Earth.
The greater the distance light travels through space and is shifted, the greater is the shift.
Vesto Slipher, an astronomer at the Lowell Observatory in Flagstaff, Arizona, was finishing a detailed study of the night
sky. He examined several of the faint, fuzzy "nebulae" that he saw in his telescope. He carefully measured the nebulae's
spectra - the amount of light they emitted at different wavelengths. He found that the spectra of nearly all of them were
"redshifted" - their light was redder than it should have been. Slipher knew that when an object's light was redshifted, it
was moving away from Earth, and that the object's speed was proportional to the redshift. He calculated the nebulae's
speeds, and found they were all moving away from us incredibly quickly:
It wasn’t really Hubble who came up with the idea. He simply took or was given credit for Slipher’s work.
Two main question emerge.
- Is there other proof of expanding universe other than Redshift? - NO
- Could the redshift be from something other the object moving away? - YES
The distances between stellar bodies is not increasing proportional to the redshift.
Since empty space is not empty, there is a lot of stuff for light to go through and be shifted. Simply put,
there is interactions and phenomena in the subjects of radiative transfer and physical optics which cause
The greater the distance light travels through stuff in space and is shifted, the greater
is the shift... DUH.
Copyright 13 oct 2011
|Doppler effect proves relative light speed.
The diagrams at the linked page show how light waves outside the emitter medium are altered as
compared to the waves inside the emitter medium. The animation needs to be expanded to include
observers inside the car which are equally valid observers.
Consider a light source inside a car. The light inside the car is not Doppler shifted inside the car as long as
the car is in uniform motion. The same light leaves the car and becomes Doppler shifted. The same applies
to sound. Observations and measurements outside the car and inside the car are both equally valid. The car
observer is moving relative the light and emitter so the light and sound is not shifted to them. The car and
it's emitter is moving relative to the ground so the light and sound outside the car is shifted relative to
them. That gives light that changes from not Doppler shifted to shifted. The same type of effect occurs with
regard to the speed of light. Inside the car, the light goes c compared to the car. When the light leaves the
car, it changes speed to go c as compared to the earth. The Galilean transformation applies to light.
Doppler effect proves modified relative emitter theory and relative light speed.
and inside observers do not know the observations of the other because he does not allow all observers to
have equally valid information of equally valid observers.
Copyright. Don E. Sprague 2007 13 oct 2011
|There is no proof of an expanding universe other than Redshift that is actually Interstellar reddening.
- Interstellar reddening removes shorter wavelength photons leaving behind longer wavelength photons.
- Redshift is longer wavelength associated with an emitter moving away from the observer.
Both provide longer wave length for the observer to determine,
- is the red from Interstellar reddening from interference, or
- is the red from moving emitter theory that cause the reddening.
We accept that some redshift is from the light source moving away. We accept blueshift is from light
sources moving toward us. There are some blueshift and some redshift associated with light source
movement toward and away from us. We should expect the numbers of the two to be similar. We should
not expect the extent of the disproportionate large number of red to be from the light source moving
away. We should expect that most of the red is from Interstellar reddening. We should also expect that
some of the blueshift has been altered by Interstellar reddening
This is similar to the old concept of tired light.
Copyright. Don E. Sprague 2007 13 oct 2011
To explain the concept of how light and other things interact in a force field, I begin with a somewhat
appropriate analogy. Consider the force at the center of a muddy river. A suspended tiny particle flows
along almost unencumbered while a log on the surface flows along with more encumbrances. The analogy
isn’t exact but substitutions should convey the concept. On a very long river with very uniform flow, a log
will proceed at almost the same velocity of the water. Water and a tiny particle will flow past the log.
-The flow/force of the river would seemingly not exist compared to the log.
- A casual observer would not perceive motion of the water or the tiny particle.
- A skilled observer with precise tools could observer the flow.
Consider that, like a log on a river, the earth moves because of forces. If the forces were removed, the
earth would stop moving and spinning. That is because space is not empty. It is very thin. We basically
say that light travels “c” in an observer’s frame of reference vacuum. Consider instead that light travels “c”
compared to an observers force field vacuum.
With that we have:
- A force field propels the earth.
— The earth resists the force field so it somewhat lags the force field.
- A force field that light travels within omnidirectional unencumbered.
The earth resists the force field so the earth movement is slightly behind the force field. Light speed is not
actually relative to earth. It is relative to the earth force field.
This applies with relative speed of light. That is, light is relative to the frame or force field just as it is
relative to different mediums.
Copyright Don E. Sprague 2007 edited 04 Oct 2011
Black hole- Center Mass vs Center of Mass
Don E. Sprague Copyright.
There is no observable difference between a black hole described as having a center mass compared to one
described as having a center of mass. You can not see a center mass but it can supposedly be measured.
However; a center of mass can actually be measured through calculations.
THE THEORY OF COMPLEX and HIERARCHY of RELATIVITY
If you have not read Einstein's paper on relativity, how can
you argue it's merit? The following is an examination of
What would most people think if I said that the truth is not true and I have proof? Well that is what Albert
Einstein did in his paper.
Albert said: “For the present we shall assume the truth of the geometrical propositions, then at a later stage
(in the general theory of relativity) we shall see that this truth is limited, and we shall consider the extent of its
|Einstein's flaw explained
Since Einstein's theories were first accepted, the science community has always said that his theories are the
most accurate of all flawed theories. Obviously a flawed theory is just another wrong theory.
Einstein's flaw begins with his train thought experiment with a person who does not know they are on a
moving train so the don't use all the facts when considering origin times of simultaneous lightning strike.
When the person uses all the data, they can calculate the speed and distance of the train to verify the
simultaneous time of the lightning strikes.
Einstein's singularity flaw is a result of the initial error introduced in section 9 of his paper. Eliminate the
beginning of the error in section 9 results in elimination of the singularity flaw at the end.
Classical Mechanics (CM) was considered to be incomplete. After Einstein, CM ic considered to be flawed
because it does not conform with Einstein's known wrong theory.
MOBILE COMPUTING DEVICE CONTROL SYSTEM
A texting driver is a dangerous driver. There is a simple way to disable all cell phones when they exceed the
average walking speed. There is also a way to override the disable function to permit passengers and first
responders to use their phones. There is a way to disable cell phones in use restricted areas such as
Read more at internet1949.com
Enhanced Cyber Security; Control System invention
t is best to find and eliminate the cause of a problem instead of treating the symptom or trying things and
hoping they fix the problem. TELNET is said to be the first code installed on computers to enable remote
takeover of a computer. Before 1983 when TELNET was first installed, it was impossible to hack a computer.
Cyber security requirements: There are four main general requirements and many specific detail
1. Remove TELNET and all subsequent code that permits remote takeover or hacking. Closing existing
openings that permit code activation when clicking on any link in an email or site.
2. Enable remote communication but not remote control. Install access security managers that take business
requests then hand off formatted dated. This enables business but blocks remote takeover hacking.
3. Establish national and international public databases that provide real documentation about all end
users, applications and sites. This enable individuals, and enterprises to control trading partner activity
based on real data before enabling communication through their access security manager.
4. Implement enhanced local and remote logon. Once the user is securely known to the local device, the
remote session can be managed by secure computer to computer access manager control making legacy
remote Ids and passwords obsolete.
Those requirements and more are addressed in the ENHANCED ONLINE COMPUTER ACCESS CYBER
Read more at internet1949.com
Internet Timeline 1949 to 1996
Sage, initiated in 1949, the first computer network.
SABRE, Initiated in 1953, the first online order and the first online order application.
IBM Information Network, the first network designed and implemented to interconnect all networks for any
The popular descriptions of the history of the Internet are basically correct as far they go. They describe a
DARPA and ARPANET centric path to the Internet. They do not include the first computer network which was
initiated in 1949 or the first online order application which was initiated in 1953. The first file transfer was
on SAGE which was running years before ARPANET was first imagined. The first online order application was
running before the ARPANET was imagined. There are many things that are left out of the popular
description of the Internet history.
Read more at internet1949.com
IBM Information NetworkIn 1982
The IBM Information Network (IBM IN), later named the IBM Global Network (IBM GN), was the first online
service provider to focus on open multi-enterprise online interconnection of networks. In just a few years,
IBM IN grew from nothing to the world leader and model for any to any online activity. By 1996 when it
converted from IBM SNA to IP, the IBM GN had grown to be the world's largest most successful commercial
online service provider.
Read more at internet1949.com
|Hierarchy of Relativity Introduction
Constant Space, Constant time, Relative Light.
The history of things like weather predictions has been filled with mistakes. Everyone makes mistakes in every
field. They are like having a splinter in your finger. It feels good to get the splinter out and it sure feels good
when your mistake is corrected. We basically know how the weather is predicted. Collect historical data and
project into the future. Using the laws of physics and data about the time things happed at a place on earth
enables projection of possible future weather events. The same applies to projections of bodies in space. It is
widely accepted that the laws of physics are the same everywhere and the speed of light is the same
everywhere. That believe is linked to Albert Einstein’s paper on the Theory of Relativity.
These two widely known quotes are referred to as the consequences of Special Relativity
The speed of light is the same for all observers, no matter what their relative speeds.
The laws of physics are the same in any inertial (that is, non-accelerated) frame of reference. This means that the
laws of physics observed by a hypothetical observer traveling with a relativistic particle must be the same as those
observed by an observer who is stationary in the laboratory.
Actually, the consequence of Einstein’s papers is the belief that space and time are not constant. However;
something about time and space must be constant because things like weather reports are getting more
accurate. If time and space are variable, how do we get a constant when we multiply a variable time by a
variable distance? It is obvious that everything we see is from the past location of objects in certain places. It
is obvious that we can predict future locations of objects based on the past. If time and space has no
meaning, then we could not have calendars. We could not land a craft on the moon if time and space were
Concerning the speed of light, every measurement of the speed of light has proven that it is constant relative
to the frame of reference where it is measured.
w = c-v and W=v+w may be the two most important formula in the Theory of relativity.
|Simultaneous shrinking ladder and shrinking garage
A ladder that is too long to fit into a garage will supposedly fit when it is moving because it’s
motion supposedly causes it to shrink.
This is purely a thought experiment. It is obviously impossible to actually conduct the imaginary
The experiment is always just as viewed from the garage. Suppose we consider the ladder as an
equally valid frame for observation. Using Einstein’s process, the ladder is stationary with the
garage moving. Thus, the garage shrinks instead of the ladder shrinking. In this case, the ladder
is even longer than the garage so the ladder doesn't fit into the garage.
Now simultaneously conduct both the shrinking ladder and shrinking garage experiments with
observers in both frames at the same time.
|Speed of light from a flashlight on a bicycle, or on a train, or on any moving container:
Consider a person holding a flashlight inside a train. Most people accept that the light from the flashlight
moves at the speed of light inside the train regardless of the speed or direction of the train. There is no
Doppler shift inside the train. There is Doppler shift outside the train.
Then a person rides a bicycle along side the train. The light is passed from the train passenger to the bicycle
rider. The speed of the flashlight didn't change. Since the speed of light is always shown to be c relative to
the earth, the speed of light from the flashlight must have changed to be c relative to the ground. That must
mean the speed of light was relative and additive to the train and changes to become relative and additive
to the moving earth. After all, the earth is continually accelerating.
My own pet theory, or part of it.
As I’m standing beyond a wall,
It looks so strange and dauntingly tall.
I can philosophically build a land,
My own world is where I stand.
I have all resource for my needs,
With thoughts that serve as growing seeds.
My own pet theory, or part of it,
Outside the wall is where I sit.
My own pet theory, or part of it,
Outside the wall is where I sit.