What is it?

In article <[email protected]>, "Mekon" <[email protected]> wrote:
>
>One of the big questions I have won a few beers with is "Why does it get
>dark at night? Most people's answer is very wrong.

We call it "night" when it gets dark, and it gets dark because the earth's
rotation has moved the observer from the sunlit side to the shadow side.

Do I win a prize? (even if it's just the booby prize)

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Morris Dovey wrote:
>
> Time may be another fly in the ointment. AFAICT, it's flow is speeding
> up - and from first-hand observation, every year flies past just a bit
> faster (and every winter comes just a bit sooner) than it did the year
> before...

I thought it was just me! This is going to screw _everything_ up. If
the days are getting shorter do we need to make calendars smaller?
When kids are playing hide and go seek, are they supposed to count "one
nine hundred and ninety nine (or whatever)"? Wouldn't that make a
second longer? I was going to go lie down, but what's the point? I'll
probably have to get up before I lie down.

R

[email protected] wrote:
> >> We call it "night" when it gets dark, and it gets dark because the earth's
> >> rotation has moved the observer from the sunlit side to the shadow side.
> >>
> >> Do I win a prize? (even if it's just the booby prize)
> >>
> >>
> >That is the answer that most folks give. It is wrong in that it is
> >incomplete - it's a bit like saying cars move because there is fuel in the
> >tanks.
> >
> >If you stand anywhere and point to the sky anywhere you will be pointing at
> >a star, even if you point to an apparently empty place there is a star that
> >is too far away for you to see. The light it emits began to shine a long
> >time ago, but not long enough to reach you.If the universe has been here
> >forever then the light from every star would have had the time to reach you
> >and the night sky would be a blaze of light. Consequently it is dark at
> >night because the universe is of a certain finite age.
> >
> >
>
> That is the MOST wrong thing I have read tonight!

Why do you feel that way?

R

"Mekon" <[email protected]> wrote in
news:[email protected]:

*snip*

>
> One of the big questions I have won a few beers with is "Why does it
> get dark at night? Most people's answer is very wrong.
>
>
> Mekon
>

It gets dark at night? I've heard rumors from people in sparsely
occupied states such as Nebraska, but have not seen it myself. ;-)

Puckdropper
--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

bent (in [email protected]) said:

| I've been wondering about a couple of things and I think they are
| just
| coming together. E=mcsquared, so I have always thought that ya
| know, this
| is evident since after the big bang, and so, you could determine
| the size of
| the universe at any time after that singularity using that
| equation, I mean
| it could be summed up. But, I have heard a lot about this
| recently, it
| occurs to me that no matter which direction you look in, you can
| see an
| equivalent amount into totality, meaning time. i.e you can see
| about 14.5
| or so billions years into the past in any which way you choose.
|
| Interesting. Unless time is slowing down. The question is, now
| that we
| have the fundamentals, what gives? Does it not follow that since
| this
| equation has a static finite constant answer that there must be a
| unknown
| variable that allows for the discrepancy in the equation. I am
| interested
| in what this may be. Is it free love, or a planet with an
| unlimited supply
| of ebony?

Hmm. Just to start your week off right I thought I'd mention that c
doesn't appear to be quite as constant as we used to think. In 2000
UCB (I think) reported that measurements varied with the medium
through which light is passing, with vacuum /not/ being the fastest
medium.

Time may be another fly in the ointment. AFAICT, it's flow is speeding
up - and from first-hand observation, every year flies past just a bit
faster (and every winter comes just a bit sooner) than it did the year
before...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

In article <[email protected]>, "Mekon" <[email protected]> wrote:
>
>This does a neat job of explaining away the inverse law...
>
>http://science.howstuffworks.com/question691.htm

Yeah, sort of -- but it depends on the (unproven) assumption that the
distribution of stars in the universe is uniform; a glance at the night sky
suggests that this is a pretty shaky assumption.

>Still, if we ever find ourselves in the same city at the same time, the
>first beer is on me. :)

I don't travel much... let me know next time you're going to be in
Indianapolis, OK?

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

In article <[email protected]>, "Mekon" <[email protected]> wrote:
>
>"Doug Miller" <[email protected]> wrote in message
>news:[email protected]...
>> In article <[email protected]>, "Mekon"
><[email protected]> wrote:
>> >
>> >One of the big questions I have won a few beers with is "Why does it get
>> >dark at night? Most people's answer is very wrong.
>>
>> We call it "night" when it gets dark, and it gets dark because the earth's
>> rotation has moved the observer from the sunlit side to the shadow side.
>>
>> Do I win a prize? (even if it's just the booby prize)
>>
>>
>That is the answer that most folks give. It is wrong in that it is
>incomplete - it's a bit like saying cars move because there is fuel in the
>tanks.

Baloney. It's a complete, and completely correct, answer. It's dark at night
because the sun isn't lighting up that side of the earth.

>If you stand anywhere and point to the sky anywhere you will be pointing at
>a star, even if you point to an apparently empty place there is a star that
>is too far away for you to see.

Unproven assumption -- and I believe an incorrect one besides, as it appears
to be equivalent to assuming that the number of stars is infinite. But we'll
let that pass for now, because you have worse things amiss.

>The light it emits began to shine a long
>time ago, but not long enough to reach you.If the universe has been here
>forever then the light from every star would have had the time to reach you
>and the night sky would be a blaze of light. Consequently it is dark at
>night because the universe is of a certain finite age.

Nonsense. Your "explanation" ignores two things:

First, stars have a *finite* lifespan. Even being of "a certain finite age",
the universe is already plenty old enough that some stars have already ceased
to shine, and consequently they are incapable of illuminating this planet, or
anything else. If the universe were infinitely old, the number of dead stars
would be even greater. (This is also one reason why I believe that your
assumption which I noted above is incorrect.)

Second, you're forgetting about the inverse square law -- the farther away a
light source is, the lower the intensity of light, in direct proportion to the
*square* of the distance. The nearest star to this planet (the sun) is about 8
light-minutes away. The next nearest is four-point-something light-YEARS
away, or over two *million* light-minutes. Suppose for the sake of
illustration that the two emit the same amount of light -- then the intensity
of the light reaching us from the latter is approximately 0.000000000015 times
as intense as from the former. Other stars are even farther away; the
overwhelming majority are *much* farther away, and the intensity of their
light reaching Earth is *much*-squared fainter.

You owe me a beer.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

"Doug Miller" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, "Mekon"
<[email protected]> wrote:
> >
> >One of the big questions I have won a few beers with is "Why does it get
> >dark at night? Most people's answer is very wrong.
>
> We call it "night" when it gets dark, and it gets dark because the earth's
> rotation has moved the observer from the sunlit side to the shadow side.
>
> Do I win a prize? (even if it's just the booby prize)
>
>
That is the answer that most folks give. It is wrong in that it is
incomplete - it's a bit like saying cars move because there is fuel in the
tanks.

If you stand anywhere and point to the sky anywhere you will be pointing at
a star, even if you point to an apparently empty place there is a star that
is too far away for you to see. The light it emits began to shine a long
time ago, but not long enough to reach you.If the universe has been here
forever then the light from every star would have had the time to reach you
and the night sky would be a blaze of light. Consequently it is dark at
night because the universe is of a certain finite age.


Mekon

"bent" <[email protected]> wrote in message
news:[email protected]...
> I've been wondering about a couple of things and I think they are just
> coming together. E=mcsquared, so I have always thought that ya know, this
> is evident since after the big bang, and so, you could determine the size
of
> the universe at any time after that singularity using that equation, I
mean
> it could be summed up. But, I have heard a lot about this recently, it
> occurs to me that no matter which direction you look in, you can see an
> equivalent amount into totality, meaning time. i.e you can see about 14.5
> or so billions years into the past in any which way you choose.\\

But isn't time/space curved? So that wherever you look you are looking at
the back of your own head - it is just that the light hasn't hsd enough time
to reach your eyes.


>
> Interesting. Unless time is slowing down. The question is, now that we
> have the fundamentals, what gives?


I don't think we have nailed *all* the fundementals as yet, e.g. we still
haven't got a handle on how much matter there is and what this 'dark matter
' stuff is.

It will be pretty tedious once all the big questions are answered, but I
don't expect that to be a problem in my lifetime.

> Does it not follow that since this
> equation has a static finite constant answer that there must be a unknown
> variable that allows for the discrepancy in the equation. I am interested
> in what this may be.


> Is it free love, or a planet with an unlimited supply
> of ebony?


You wish. I think it is the variable of exactly how much mass was created at
the singularity., Once we know that lots of stuff should fall into place.

As for planets with unlimited supplies of ebony or anything else for that
matter, you know that is impossible, simply because a planet is a finite
size and is therefore limited. However we can dream.


Until then we have to settle for what we have. And that's fine by me.

One of the big questions I have won a few beers with is "Why does it get
dark at night? Most people's answer is very wrong.


Mekon

(snip)

> You owe me a beer.
>
> --

I'm happy to buy you a beer, not so happy about admitting being wrong
though... :)

I think I first read it in Stephen Hawkins Brief History of Time, But it may
have been from Carl Sagan, neither reference is available to me at the
moment. But these are:

I seem to be on shaky ground (as in I can't find a reference) on the stars
are everywhere bit, and missed the relevance of the expanding universe.
But these back up the finite age bit.

http://www.astro.ucla.edu/~wright/cosmology_faq.html#OP

http://curious.astro.cornell.edu/question.php?number=375

This does a neat job of explaining away the inverse law...

http://science.howstuffworks.com/question691.htm

Still, if we ever find ourselves in the same city at the same time, the
first beer is on me. :)

Mekon

>> We call it "night" when it gets dark, and it gets dark because the earth's
>> rotation has moved the observer from the sunlit side to the shadow side.
>>
>> Do I win a prize? (even if it's just the booby prize)
>>
>>
>That is the answer that most folks give. It is wrong in that it is
>incomplete - it's a bit like saying cars move because there is fuel in the
>tanks.
>
>If you stand anywhere and point to the sky anywhere you will be pointing at
>a star, even if you point to an apparently empty place there is a star that
>is too far away for you to see. The light it emits began to shine a long
>time ago, but not long enough to reach you.If the universe has been here
>forever then the light from every star would have had the time to reach you
>and the night sky would be a blaze of light. Consequently it is dark at
>night because the universe is of a certain finite age.
>
>
>Mekon
>
>

That is the MOST wrong thing I have read tonight!

--
Make it as simple as possible, but no simpler.

Larry Wasserman - Baltimore Maryland - [email protected]

"Doug Miller" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, "Mekon"
<[email protected]> wrote:
> >
> >This does a neat job of explaining away the inverse law...
> >
> >http://science.howstuffworks.com/question691.htm
>
> Yeah, sort of -- but it depends on the (unproven) assumption that the
> distribution of stars in the universe is uniform; a glance at the night
sky
> suggests that this is a pretty shaky assumption.

In the night sky you are mostly only seeing one galaxy, the milky way. and
there are millions.

>
> >Still, if we ever find ourselves in the same city at the same time, the
> >first beer is on me. :)
>
> I don't travel much... let me know next time you're going to be in
> Indianapolis, OK?
>
>

I travel a lot and Indianapolis is one US city I haven't seen... yet.

Mekon