Howard wrote:
"Mucho Grande" wrote in message
ups.com...

Howard wrote:
"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty


If the object is not transparent, then the table would not appear empty.
Light would not pass through the object, so you couldn't see the table
beneath it. (And it would cast a shadow on the table from any light
source
above.) Assuming one can create an object which neither reflects nor
emits
visible light, what you would see (with normal vision) would be a
blackness
where the object is.

This is much like an LCD crystal, where the light is scattered so that
when
you look at it (from in front), you see black lines.

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?


My sense of touch is not constrained by the visible spectrum. I can feel
heat, for example, but not see it.

would this invisible object be existing?



Sure, why not?

you cannot say that light is wave and/or particle

light is much more than that


You lost me there.

-Howard

and what makes you think that UV spectrum would
block for light in visible spectrum, it doesnt happen in
nature

then why dark and not completly enlightened


I can't tell if I'm having more trouble understanding your logic, or your
English. What are you talking about?

it must be my english, because you cant support your own statements

you just said

what you would see (with normal vision) would be a
blackness
where the object is.


Who said anything about "UV spectrum" blocking the "visible spectrum"? I'm
talking about an object.

you said

If light simply passes through the object, then it
is by definition transparent, in whatever spectrum you choose. Yet you
stated you did not mean a transparent object.

there are no 100% transparencies, so it will still be visible,
reflections,
difractions, refraction, scatterings and such


So which is it?

i asked first


-Howard

Dear Mucho Grande:

"Mucho Grande" wrote in message
oups.com...

dlzc wrote:
Dear Mucho Grande:

Mucho Grande wrote:
...
wait a minute, lets an object be only visible
outside the visible spectrum, say UV eller IR,
so we cant see it
...
would this invisible object be existing?

Pure diamond has no emission bands in the
visible light region. Do diamonds exist?

is been said that transparency means visible, and
is visible indeed

So empty space, or nothingness, is perfectly transparent. Does
nothingness exist?

imagine complet invisible

please read again

You have defined yourself into a corner. How will you get out?

David A. Smith

"Mucho Grande" wrote in message
ups.com...

Bill Hobba wrote:
"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

No entirely transparent object exists.

Bill

Dear Mister Bill

thank you for your feedback, i think you are right

could you elaborate a bit?

the other posters just said that the object still exists

Not from my reading of what at least one of them said.

No known object has zero effect on EM radiation in the visible spectrum.
Even air, which you think may, refracts light differently depending on
temperature. If you are trying to find issues with physics by means of
thought experiments concerning things that do not actually exist; you will
fail.

Bill





wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

would this invisible object be existing?

you cannot say that light is wave and/or particle

light is much more than that

Mucho Grande wrote:
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty

If it were transparent, then you'd be able to see the table through it.
Since it is not transparent, it is occluding part of the table, which
will make its presence rather obvious.

Indeed, if it is neither radiating, nor reflecting, radiation in the
visible region, then it will appear as a black solid. We do not normally
regard black solids as being invisible.

You are essentially defining an object with mutually exclusive
properties. Since such an object cannot exist, you cannot meaningfully
ask questions about it.

Sylvia.



now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

would this invisible object be existing?

you cannot say that light is wave and/or particle

light is much more than that

Mucho Grande wrote:
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty
You will see a black object.
All visible colours are absorbed. UV or IR are reflected from the
objects surface but we cannot see the UV or IR so the object is black
in colour to us.

Try this experiment.
Yellow light = Red light + Green light
Put a yellow glass in front of your eye. It can turn blue objects
black.
Explanation: Red and green light are absorbed by the blue object and
only blue light is reflected. Blue light cannot pass through the
yellow glass. Since no visible light can reach to your eye, you will
see a black object.

Transparent is different. Light can pass through a transparent object
to reach your eye, so you can see the object behind.

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

would this invisible object be existing?
Have you ever bump your head on the window? A colourless glass can be
classified as an invisible object. It is not perfectly invisible
because it's refractive index is much greater than 1. The image
through the glass usually does not fit perfectly with background.

you cannot say that light is wave and/or particle

light is much more than that

On Dec 7, 3:23 pm, "Mucho Grande" wrote:
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

would this invisible object be existing?

Yes, of course it does. Invisibility has nothing to do with existence.

First of all, let's examine your hypothetical situation. Unless they
are hot compared to the environment, visible objects *reflect* or
*scatter* light that is incident on them, and so the light that comes
from them is actually due to an external source. There are some objects
that absorb some of the wavelength incident on them and reflect some --
for example, a banana reflects light in the yellow-green portion of the
visible spectrum but absorbs light from the violet and red ends of the
spectrum. Things that absorb all incident light in the visible spectrum
appear black to us --- far from invisible.

What you apparently want to imagine is something that is *transparent*
to all light in the visible spectrum, which means that if the object
were sitting on a table, then all light scattered from the table would
proceed through the transparent object unimpeded, unabsorbed,
unscattered to your eyes. This also is not unusual, as anyone who has
walked into a closed sliding glass door can tell you.

Finally, if you want to probe the true nature of light by considering
hypothetical objects, it's probably best to consider hypothetical
objects that have some bearing to reality.


you cannot say that light is wave and/or particle

That's right. Light has properties of both.


light is much more than that

Yes, indeed. And much more than that is already understood about light,
if you care to read further. I suggest a small book called QED by
Richard Feynman.

PD

N:dlzc D:aol T:com (dlzc) wrote:
Dear Mucho Grande:

"Mucho Grande" wrote in message
oups.com...

dlzc wrote:
Dear Mucho Grande:

Mucho Grande wrote:
...
wait a minute, lets an object be only visible
outside the visible spectrum, say UV eller IR,
so we cant see it
...
would this invisible object be existing?

Pure diamond has no emission bands in the
visible light region. Do diamonds exist?

is been said that transparency means visible, and
is visible indeed

So empty space, or nothingness, is perfectly transparent. Does
nothingness exist?

lisent, i ask the questions here


imagine complet invisible

please read again

You have defined yourself into a corner. How will you get out?

me!? you mean you

the quaetsion is simple

are obejcts only visible/detectable outside the visible spectrum
existing? (matterial)


David A. Smith

wahaha, the closed answer to this question is been
given by bill hobba, i thought ill say that

Bill Hobba wrote:
"Mucho Grande" wrote in message
ups.com...

Bill Hobba wrote:
"Mucho Grande" wrote in message
oups.com...
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

No entirely transparent object exists.

Bill

Dear Mister Bill

thank you for your feedback, i think you are right

could you elaborate a bit?

the other posters just said that the object still exists

Not from my reading of what at least one of them said.

No known object has zero effect on EM radiation in the visible spectrum.
Even air, which you think may, refracts light differently depending on
temperature. If you are trying to find issues with physics by means of
thought experiments concerning things that do not actually exist; you will
fail.

Bill

you know what, you been actually the closest understanding tha
situation, than i wold had gave you 10 poings, but you are chiken****,
following the currents and streamlines, therefore you only get 5
poings
for now

be happy, the others only gets between 0 and 2 poings






wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

would this invisible object be existing?

you cannot say that light is wave and/or particle

light is much more than that

PD wrote:
On Dec 7, 3:23 pm, "Mucho Grande" wrote:
i though i understod light, but this is wird, maybe
i forget the explanation, her it comes

our eyes can detect light EM in the visible spectrum,
say lambda 700nm to 400nm, which is very nice

wait a minute, lets an object be only visible outside the
visible spectrum, say UV eller IR, so we cant see it

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty

now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

would this invisible object be existing?

Yes, of course it does. Invisibility has nothing to do with existence.

this is an wonderful thing, would this object also be
matterial or imatterial, only matterializin when appearing
into tha visble spectrum?


First of all, let's examine your hypothetical situation. Unless they
are hot compared to the environment, visible objects *reflect* or
*scatter* light that is incident on them, and so the light that comes
from them is actually due to an external source. There are some objects
that absorb some of the wavelength incident on them and reflect some --
for example, a banana reflects light in the yellow-green portion of the
visible spectrum but absorbs light from the violet and red ends of the
spectrum. Things that absorb all incident light in the visible spectrum
appear black to us --- far from invisible.

you contradict yourself here, you just said it exists

if not visible is tha object exiting or not

this is wordsalad, has nothen ta do with the situation


What you apparently want to imagine is something that is *transparent*
to all light in the visible spectrum, which means that if the object
were sitting on a table, then all light scattered from the table would
proceed through the transparent object unimpeded, unabsorbed,
unscattered to your eyes. This also is not unusual, as anyone who has
walked into a closed sliding glass door can tell you.

no, how many times do i have to say that i dont mean transparency
whatso any fokn ever


Finally, if you want to probe the true nature of light by considering
hypothetical objects, it's probably best to consider hypothetical
objects that have some bearing to reality.

what reality

are you implaing that objects only detectable outside tha visble
spectrum are not real enuff?



you cannot say that light is wave and/or particle

That's right. Light has properties of both.

wrong, i just that it is much more than that



light is much more than that

Yes, indeed. And much more than that is already understood about light,
if you care to read further. I suggest a small book called QED by
Richard Feynman.

rather you should recomand one for your selv

aparently only hobba sensed the problematics here, maybe
this is becos he is doin qm so intensively


PD

Mucho Grande wrote:

wait a while, we make it simple, suppose that this
object lay on your table, you cant see it so it is
invisible, do not confuse, it is not transparent, because
if it were then you could see it, you don see anything on
your table, your table seems empty

If it were transparent, we might see it if it affected light in some
way, for example by refraction. Since the substance is hypothetical,
then it might not refract light at all. It need not be so simple as
glass or water.


now, if you drag your hand on your table will you sense it,
will you touch and detect its shape?

Since it's hypothetical, we don't know. Probably not.

would this invisible object be existing?

It might conceivably be detectable gravitationally. But then it should
affect light.

You haven't found some "dark matter", have you?

you cannot say that light is wave and/or particle

light is much more than that

Maybe light is waving "dark matter" - only visible if you can see it.

It's beginning to look a lot like ether. (Sorry Santa, but it's very
white outside).

Barry