I once heard that everything is relative, except the speed of light,
which is absolute...

is that true really? if living things cannot see, and therefore not
be able to see light, then maybe we will think everything is relative,
as we don't know light exists.

we often hear that when the speed of an object increases (close to the
speed of light), then its mass increases, and its length decreases...
is it "absolute speed" here or "relative speed"? is it true that only
an observer which sees that object moving close to the speed of light
will measure that increase of mass and decrease of length, but let's
say there is an ant on that moving object, the ant won't measure the
object having increased mass and decreased length.

(once i heard that an object cannot move faster than the speed of
light, as the mass will approach infinity and therefore no energy is
enough to make it move faster... so is that not true, since its mass
according to the ant is unchanged).

sorry can things be discussed as if it is explained to a 10-year
old? Thanks very much for answering to such a simplistic question.

"liketofindoutwhy" wrote in message
...
|I once heard that everything is relative, except the speed of light,
| which is absolute...
|
| is that true really?

No.


Einstein said
the speed of light from A to B is c-v,
the speed of light from B to A is c+v,
The "time" each way is the same. "Time" is not the same as time
in Einstein's world and Einstein was a raving lunatic. THAT is
what is true really.

"Martin Hogbin" wrote in message
...
| Androcles wrote:
| "liketofindoutwhy" wrote in message
|
...
| |I once heard that everything is relative, except the speed of light,
| | which is absolute...
| |
| | is that true really?
|
| No.
|
|
| Einstein said
| the speed of light from A to B is c-v,
| the speed of light from B to A is c+v,
| The "time" each way is the same. "Time" is not the same as time
| in Einstein's world and Einstein was a raving lunatic. THAT is
| what is true really.
|
| There many complete crackpots on this group. They are
| generally not too hard to spot.
|
Figured out how to measure the speed of a train yet, complete crackpot?

Androcles wrote:
"liketofindoutwhy" wrote in message
...
|I once heard that everything is relative, except the speed of light,
| which is absolute...
|
| is that true really?

No.


Einstein said
the speed of light from A to B is c-v,
the speed of light from B to A is c+v,
The "time" each way is the same. "Time" is not the same as time
in Einstein's world and Einstein was a raving lunatic. THAT is
what is true really.

There many complete crackpots on this group. They are
generally not too hard to spot.

Martin Hogbin

On May 8, 7:21 pm, liketofindoutwhy
wrote:
I once heard that everything is relative, except the speed of light,
which is absolute...

is that true really? if living things cannot see, and therefore not
be able to see light, then maybe we will think everything is relative,
as we don't know light exists.

we often hear that when the speed of an object increases (close to the
speed of light), then its mass increases, and its length decreases...
is it "absolute speed" here or "relative speed"? is it true that only
an observer which sees that object moving close to the speed of light
will measure that increase of mass and decrease of length, but let's
say there is an ant on that moving object, the ant won't measure the
object having increased mass and decreased length.

(once i heard that an object cannot move faster than the speed of
light, as the mass will approach infinity and therefore no energy is
enough to make it move faster... so is that not true, since its mass
according to the ant is unchanged).

sorry can things be discussed as if it is explained to a 10-year
old? Thanks very much for answering to such a simplistic question.

Explained to a 10-year old? Well, then the speed
of light is like that of Speedy Gonzalez
http://www.youtube.com/watch?v=hpISYBPyk8Y

:-)

On May 8, 11:46*am, Albertito wrote:
On May 8, 7:21 pm, liketofindoutwhy
wrote:





I once heard that everything is relative, except the speed of light,
which is absolute...

is that true really? *if living things cannot see, and therefore not
be able to see light, then maybe we will think everything is relative,
as we don't know light exists.

we often hear that when the speed of an object increases (close to the
speed of light), then its mass increases, and its length decreases...
is it "absolute speed" here or "relative speed"? *is it true that only
an observer which sees that object moving close to the speed of light
will measure that increase of mass and decrease of length, but let's
say there is an ant on that moving object, the ant won't measure the
object having increased mass and decreased length.

(once i heard that an object cannot move faster than the speed of
light, as the mass will approach infinity and therefore no energy is
enough to make it move faster... *so is that not true, since its mass
according to the ant is unchanged).

sorry can things be discussed as if it is explained to a 10-year
old? * Thanks very much for answering to such a simplistic question.

Explained to a 10-year old? *Well, then the speed
of light is like that of Speedy Gonzalezhttp://www.youtube.com/watch?v=hpISYBPyk8Y

:-)- Hide quoted text -

- Show quoted text -

Everything is not relative but the speed of light in vacuo is the one
constant in the universe.

Mitch Raemsch

liketofindoutwhy wrote:
I once heard that everything is relative, except the speed of light,
which is absolute...

is that true really?

Pretty well. According to Einstein's theory of
relativity, which has been around for over a century,
is now fully accepted, and for which there is a vast
ammount of experimental evidence, all ineretial
observers will measure light to travel at the same speed.

if living things cannot see, and therefore not
be able to see light, then maybe we will think everything is relative,
as we don't know light exists.

I do not understand that.

we often hear that when the speed of an object increases (close to the
speed of light), then its mass increases, and its length decreases...
is it "absolute speed" here or "relative speed"?

It is relative speed that matters. There is no
absolute speed (except for light in a certain sense).

If I am in motion relative to you then you will measure
me to be contracted along the line of relative motion,
but you will measure me to be contracted. Weird, but
that how things seem to be.

is it true that only
an observer which sees that object moving close to the speed of light
will measure that increase of mass and decrease of length, but let's
say there is an ant on that moving object, the ant won't measure the
object having increased mass and decreased length.

Correct.

(once i heard that an object cannot move faster than the speed of
light, as the mass will approach infinity and therefore no energy is
enough to make it move faster... so is that not true, since its mass
according to the ant is unchanged).

No object can travel at the speed of light, measured
relative to any other inertial object.


Martin Hogbin

On May 8, 12:52 pm, wrote:

Everything is not relative but the speed of light in vacuo is the one
constant in the universe.

Mitch Raemsch

everything is not relative? is that right -- is that what relativity
is really is? I thought even in Newton's physics, speed is relative,
so maybe Einstein's theory is different in this regard? When we say
"something approaches the speed of light", is that absolute speed or
relative to the observer?

"Martin Hogbin" wrote in message
...
| liketofindoutwhy wrote:
| I once heard that everything is relative, except the speed of light,
| which is absolute...
|
| is that true really?
|
| Pretty well. According to Einstein's theory of
| relativity, which has been around for over a century,
| is now fully accepted,

HAHAHA!
By you, maybe.

Relativity says:
the speed of light from A to B is c-v,
the speed of light from B to A is c+v,
the "time" each way is the same.
IDIOT!

Dear liketofindoutwhy:

"liketofindoutwhy" wrote in message
...
I once heard that everything is relative, except
the speed of light, which is absolute...

As far as we can tell, yes.

is that true really?

"Really" is for religions and philosphy. All we know is what we
can measure.

if living things cannot see, and therefore not be
able to see light, then maybe we will think
everything is relative, as we don't know light
exists.

If you want to go back to a preanimate state, we can't know
anything at all. We cannot see infrared (or less energetic), or
ultraviolet (or more energetic), but we can still measure speed
of that light. And relativity predates a real value of the speed
of light by a few years... it started with Galileo (as history
relates it).

we often hear that when the speed of an
object increases (close to the speed of light),
then its mass increases,

No, but its energy does, as measured in a rest frame.

and its length decreases...

.... only as measured by a rest frame. Everything in the "moving"
frame seems normal.

is it "absolute speed" here or "relative speed"?

Relative... to the "stationary" frame.

is it true that only an observer which sees that
object moving close to the speed of light will
measure that increase of mass and decrease
of length,

Yes, as far as we can measure.

but let's say there is an ant on that moving
object, the ant won't measure the object
having increased mass and decreased length.

Correct.

(once i heard that an object cannot move
faster than the speed of light, as the mass

.... energy ...

will approach infinity and therefore no energy is
enough to make it move faster...

Right, once it has infinite energy, there is no more to give it.

so is that not true, since its mass according
to the ant is unchanged).

Rest mass of both the object and the ant is unchanged, regardless
of speed.

sorry can things be discussed as if it is
explained to a 10-year old? Thanks very much
for answering to such a simplistic question.

http://hermes.physics.adelaide.edu.a...y/SR/mass.html

David A. Smith