| Topic: |
Science > Physics |
| User: |
"Ian Macmillan" |
| Date: |
01 Oct 2005 09:55:05 AM |
| Object: |
Relativity for Nongs |
Special Relativity is a theory that says that time is intrinsic to
distance, and looks at the consequences where there is no accelleration.
Nothing can be seen to travel any distance without also travelling its
intrinsic time, which is about one nanosecond per foot. No distance can
be travelled in less than this time any more than any distance can be
travelled in less than that distance.
Lightspeed is limited only by the time intrinsic to distance, so that the
speed of light appears as constant. We speak of the "speed of light",
but it is more useful to think "nanoseconds per foot", rather than "feet
per nanosecond".
The principle of Relativity says that, as there is nothing to refer to in
space, motion can only be measured as being relative between bodies.
An inertial frame is a collection of points at mutual rest. All the laws
of nature are the same inside each and every inertial frame.
If inertial frames are in mutual motion, times measured in one frame will
differ from those measured in the other because motion is travel through
time as well as distance.
If relative times differ, so will the intrinsicly related distances.
Imagine a flying clock passing two points on your inertial frame. You can
photograph the clock as it passes each point, and record the time of
passing on your clocks.
The time you measure between the passings is a composition of the time
intrinsic to the distance between the points, and the time between
the passing events as shown by the flying clock.
The flying clock considers itself to be at rest, and registers the events
of two points successively flying past it, a time unaffected by distance.
The relationship between the times is that of a right angled triangle.
The time intrinsic to the distance and the time shown by the flying clock
are taken at right angles, with the transit time between the points
forming the hypotenuse.
The flying clock shows a travel time less than the transit time shown by
your clocks, because as far as it is concerned, it did not travel.
The flying clock did not run slower, it experienced less time.
Given the lesser time seen on the moving frame, and if in light speed
experiments the space-time relationship is to be maintained, lengths
there will also be seen as less in the same proportion as times.
Carefully thinking about how measurements should be made, you will see
that the relativity between moving frames is symmetrical
A bit of simple algebra will convert the time relationship I have
described to the conventional velocity relationships.
All the best
Ian Macmillan
.
|
|
| User: "Androcles Androcles@ MyPlace.org" |
|
| Title: Re: Relativity for Nongs |
01 Oct 2005 10:04:46 AM |
|
|
"Ian Macmillan" <iandmac@tpg.com.au> wrote in message
news:433ea2c7$1@dnews.tpgi.com.au...
| Special Relativity is a theory that says that time is intrinsic to
| distance, and looks at the consequences where there is no
accelleration.
[quote]
we establish by definition that the "time" required by a turtle to
travel
from A to B equals the "time" it requires to travel from B to A.
[end quote]
Ref: http://www.fourmilab.ch/etexts/einstein/specrel/www/
[quote]
For velocities greater than that of a turtle our deliberations become
meaningless; we shall, however, find in what follows, that the velocity
of a turtle in our theory plays the part, physically, of an infinitely
great velocity.
[quote]
Ref: http://www.fourmilab.ch/etexts/einstein/specrel/www/
Nothing can go faster than a turtle.
Oops!... Did I say 'a turtle'? Sorry...'light'.
Androcles.
|
| Nothing can be seen to travel any distance without also travelling its
| intrinsic time, which is about one nanosecond per foot. No distance
can
| be travelled in less than this time any more than any distance can be
| travelled in less than that distance.
|
| Lightspeed is limited only by the time intrinsic to distance, so that
the
| speed of light appears as constant. We speak of the "speed of light",
| but it is more useful to think "nanoseconds per foot", rather than
"feet
| per nanosecond".
|
| The principle of Relativity says that, as there is nothing to refer to
in
| space, motion can only be measured as being relative between bodies.
|
| An inertial frame is a collection of points at mutual rest. All the
laws
| of nature are the same inside each and every inertial frame.
|
| If inertial frames are in mutual motion, times measured in one frame
will
| differ from those measured in the other because motion is travel
through
| time as well as distance.
|
| If relative times differ, so will the intrinsicly related distances.
|
| Imagine a flying clock passing two points on your inertial frame. You
can
| photograph the clock as it passes each point, and record the time of
| passing on your clocks.
|
| The time you measure between the passings is a composition of the time
| intrinsic to the distance between the points, and the time between
| the passing events as shown by the flying clock.
|
| The flying clock considers itself to be at rest, and registers the
events
| of two points successively flying past it, a time unaffected by
distance.
|
| The relationship between the times is that of a right angled triangle.
| The time intrinsic to the distance and the time shown by the flying
clock
| are taken at right angles, with the transit time between the points
| forming the hypotenuse.
|
| The flying clock shows a travel time less than the transit time shown
by
| your clocks, because as far as it is concerned, it did not travel.
|
| The flying clock did not run slower, it experienced less time.
|
| Given the lesser time seen on the moving frame, and if in light speed
| experiments the space-time relationship is to be maintained, lengths
| there will also be seen as less in the same proportion as times.
|
| Carefully thinking about how measurements should be made, you will see
| that the relativity between moving frames is symmetrical
|
| A bit of simple algebra will convert the time relationship I have
| described to the conventional velocity relationships.
|
| All the best
| Ian Macmillan
|
|
.
|
|
|
|
| User: "Uncle Al" |
|
| Title: Re: Relativity for Nongs |
01 Oct 2005 12:39:59 PM |
|
|
Ian Macmillan wrote:
Special Relativity is a theory that says that time is intrinsic to
distance, and looks at the consequences where there is no accelleration.
No gravitation. Acceleration is included.
Nothing can be seen to travel any distance without also travelling its
intrinsic time, which is about one nanosecond per foot.
[snip]
Idiot. How do you measure distance, a long broom stick in a narrow
barn with two doors?
An inertial frame is a collection of points at mutual rest.
[snip]
Idiot.
A bit of simple algebra will convert the time relationship I have
described to the conventional velocity relationships.
SR is a self-consistent hyperbolic geometry in which information
propagation has a finite speed. The math works for *any* finite
speed. Lightspeed is arbitrary - an inserted observable.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
.
|
|
|
| User: "Ian Macmillan" |
|
| Title: Re: Relativity for Nongs |
02 Oct 2005 06:51:01 AM |
|
|
"Uncle Al" <UncleAl0@hate.spam.net> wrote in message
news:433EC9EF.1507CBAD@hate.spam.net...
Ian Macmillan wrote:
Special Relativity is a theory that says that time is intrinsic to
distance, and looks at the consequences where there is no accelleration.
No gravitation. Acceleration is included.
Well, my copy of "Concepts of Modern Physics" by Prof. A.Bieser says
that :
"...the Special Theory of Relativity...treats problems involving the motion
of frames of reference at constant velocity...with respect to one another;
the General Theory...treats problems involving frames of reference
accellerated with respect to one another."
Like me, this text is rather ancient, but I doubt that much has changed
since 1967.
Nothing can be seen to travel any distance without also travelling its
intrinsic time, which is about one nanosecond per foot.
[snip]
Idiot. How do you measure distance, a long broom stick in a narrow
barn with two doors?
Ahh! The old broomstick in the barn trick! This little problem involves
simultaniety which I have only implied in the measurement of the transit
time between the points.
After all, one can only cross so many tees and dot so many eyes in 500
words.
However I have invented nothing, nor do I assert any heresies, because all I
have done is take a different and exactly equivalent approach that I feel is
more approachable for those not steeped in hyperbolic geometry etc., and you
can approach this problem using my take on it.
An inertial frame is a collection of points at mutual rest.
[snip]
Idiot.
Well duh! Wikopedia says:
"In physics, an object has inertial motion if no external forces are being
applied to it, famously stated as Newton's first law of motion. When such an
object's state of motion is extrapolated over a region of space to take in
all other possible objects in the region with the same state of motion, and
these are used to define a common coordinate system, this system is referred
to as a frame.
Hence, a coordinate system defined by the inertial motion of objects with a
common direction and speed is called an inertial frame."
Similar, dont you think? But more than one sentence.
A bit of simple algebra will convert the time relationship I have
described to the conventional velocity relationships.
SR is a self-consistent hyperbolic geometry in which information
propagation has a finite speed. The math works for *any* finite
speed. Lightspeed is arbitrary - an inserted observable.
Sure, but lets keep it simple for now. Lightspeed is only arbitrary in
respect of units. It is the space-time ratio - or do you disagree?
All the best
Ian Macmillan
.
|
|
|
| User: "Timo Nieminen" |
|
| Title: Re: Relativity for Nongs |
02 Oct 2005 01:49:56 PM |
|
|
On Sun, 2 Oct 2005, Ian Macmillan wrote:
"Uncle Al" <UncleAl0@hate.spam.net> wrote:
Ian Macmillan wrote:
Special Relativity is a theory that says that time is intrinsic to
distance, and looks at the consequences where there is no accelleration.
No gravitation. Acceleration is included.
Well, my copy of "Concepts of Modern Physics" by Prof. A.Bieser says
that :
"...the Special Theory of Relativity...treats problems involving the motion
of frames of reference at constant velocity...with respect to one another;
the General Theory...treats problems involving frames of reference
accellerated with respect to one another."
Correct enough. STR does treat problems with frames in uniform motion
relative to each other, and GTR does treat problems with said frames in
accelerated motion.
However, consider mechanics in a single reference frame. Can you deal with
acceleration? Sure. This is about the 2nd thing taught in a physics
course. "Reference frame in uniform motion" does not mean "nothing is
accelerating", it just means that "the axes of the coordinate system are
not rotating" and "the origin of the coordinate system is not
accelerating". Nothing about the acceleration of objects.
One way to deal with acceleration in SR is to use a succession of
instantaneous rest frames. The simple version of this is to do pretty
much all of the calculation in a single frame, and only use the
instantaneous rest frame of the acceleration object to determine some
quantity that has a known and simple form in that frame, and use the
Lorentz transformations to find what that quantity is in the main
calculation frame.
You can also use accelerated frames in SR. In that case, the
transformation between frames isn't the Lorentz transformations, so some
care is needed. If the acceleration isn't constant, I doubt very much that
it's worth the effort. Since a uniformly accelerating object is dealt with
easily by the first method, uniformly accelerating references frames
aren't used much (the only case where I've seen them in practical use is
attempts to "resolve" the controversy about whether uniformly accelerated
charges radiate or not). The usual useful case is the rotating reference
frame, where the rotation is constant (so the acceleration is constant,
but not uniform). Electromagnetic problems involving rotating dielectric
parts come to mind as useful applications.
Like me, this text is rather ancient, but I doubt that much has changed
since 1967.
IIRC, I've seen SR stuff with accelerated frames used in stuff dating from
1962, but most of the papers on electromagnetics of rotating systems I've
read are later than that. Perhaps what has changed is that how to deal
with accelerated systems in SR has become more widely known. Still, even
now one sees the "no accelerated frames in SR" thing in new books, so it's
a pretty widespread myth.
--
Timo
.
|
|
|
| User: "Ian Macmillan" |
|
| Title: Re: Relativity for Nongs |
05 Oct 2005 06:53:42 AM |
|
|
"Timo Nieminen" <uqtniemi@mailbox.uq.edu.au> wrote in message
news:20051003042932.L34858@emu.uq.edu.au...
On Sun, 2 Oct 2005, Ian Macmillan wrote:
"Uncle Al" <UncleAl0@hate.spam.net> wrote:
Ian Macmillan wrote:
Timo wrote in part:
One way to deal with acceleration in SR is to use a succession of
instantaneous rest frames. The simple version of this is to do pretty
much all of the calculation in a single frame, and only use the
instantaneous rest frame of the acceleration object to determine some
quantity that has a known and simple form in that frame, and use the
Lorentz transformations to find what that quantity is in the main
calculation frame.
Given that you can calculate with accellerations using a stepwise approach,
it seems to me that if the flying clock of my example accellerated during
the course of its transit between the reference points of the rest frame,
the result
in overall relative times and distances would be the same as for an
unaccellerated transit taking the same time.
However, I wonder if the flying clock would be affected locally by the
accelleration.
You can also use accelerated frames in SR. In that case, the
transformation between frames isn't the Lorentz transformations...
Sounds to me as beyond an elementary exposition...
All the best
Ian Macmillan
.
|
|
|
| User: "Timo Nieminen" |
|
| Title: Re: Relativity for Nongs |
07 Oct 2005 01:54:30 AM |
|
|
On Wed, 5 Oct 2005, Ian Macmillan wrote:
Timo wrote in part:
One way to deal with acceleration in SR is to use a succession of
instantaneous rest frames. The simple version of this is to do pretty
much all of the calculation in a single frame, and only use the
instantaneous rest frame of the acceleration object to determine some
quantity that has a known and simple form in that frame, and use the
Lorentz transformations to find what that quantity is in the main
calculation frame.
Given that you can calculate with accellerations using a stepwise approach,
it seems to me that if the flying clock of my example accellerated during
the course of its transit between the reference points of the rest frame,
the result
in overall relative times and distances would be the same as for an
unaccellerated transit taking the same time.
Do the maths and see. What the flying clock reads at any time t, as
measured in frame X is its proper time, tau. To know the clock reading at
any time t, tau(t) = integral from 0 to t of dtau/dt dt + tau(t0). So all
you need to know is dtau/dt. This you can find using the instantaneous
rest frame of the clock - in this frame, dtau/dt = 1, by the definition of
proper time.
So dtau/dt = 1/gamma in frame X. If you know the trajectory of the clock,
you know dtau(t)/dt, and can do the integration.
--
Timo
.
|
|
|
|
|
|
|
|
| User: "Sam Wormley" |
|
| Title: Re: Relativity for Nongs |
01 Oct 2005 10:30:39 AM |
|
|
Ian Macmillan wrote:
Special Relativity is a theory that says that time is intrinsic to
distance, and looks at the consequences where there is no accelleration.
Nothing can be seen to travel any distance without also travelling its
intrinsic time, which is about one nanosecond per foot. No distance can
be travelled in less than this time any more than any distance can be
travelled in less than that distance.
Lightspeed is limited only by the time intrinsic to distance, so that the
speed of light appears as constant. We speak of the "speed of light",
but it is more useful to think "nanoseconds per foot", rather than "feet
per nanosecond".
The principle of Relativity says that, as there is nothing to refer to in
space, motion can only be measured as being relative between bodies.
An inertial frame is a collection of points at mutual rest. All the laws
of nature are the same inside each and every inertial frame.
If inertial frames are in mutual motion, times measured in one frame will
differ from those measured in the other because motion is travel through
time as well as distance.
If relative times differ, so will the intrinsicly related distances.
Imagine a flying clock passing two points on your inertial frame. You can
photograph the clock as it passes each point, and record the time of
passing on your clocks.
The time you measure between the passings is a composition of the time
intrinsic to the distance between the points, and the time between
the passing events as shown by the flying clock.
The flying clock considers itself to be at rest, and registers the events
of two points successively flying past it, a time unaffected by distance.
The relationship between the times is that of a right angled triangle.
The time intrinsic to the distance and the time shown by the flying clock
are taken at right angles, with the transit time between the points
forming the hypotenuse.
The flying clock shows a travel time less than the transit time shown by
your clocks, because as far as it is concerned, it did not travel.
The flying clock did not run slower, it experienced less time.
Given the lesser time seen on the moving frame, and if in light speed
experiments the space-time relationship is to be maintained, lengths
there will also be seen as less in the same proportion as times.
Carefully thinking about how measurements should be made, you will see
that the relativity between moving frames is symmetrical
A bit of simple algebra will convert the time relationship I have
described to the conventional velocity relationships.
All the best
Ian Macmillan
Special relativity doesn't say anything about time
being intrinsic.
http://www.fourmilab.ch/etexts/einstein/specrel/www/
In order that the two postulates of special
relativity are respected, strange things have to
happen to space and time, which, unbeknown to
Einstein, had been predicted by Lorentz and others
the previous year.
For instance, the length of an object becomes shorter
when it travels at a constant velocity, and a moving
clock runs slower than a stationary clock.
Effects like these have been verified in countless
experiments over the last 100 years.
.
|
|
|
| User: "Ian Macmillan" |
|
| Title: Re: Relativity for Nongs |
02 Oct 2005 09:19:06 PM |
|
|
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:zYx%e.379768$x96.180716@attbi_s72...
Ian Macmillan wrote:
Special Relativity is a theory that says that time is intrinsic to
distance, and looks at the consequences where there is no accelleration.
Special relativity doesn't say anything about time
being intrinsic.
(snip well known stuff)
.....But Hermann Minkowski said....
"Henceforth space by itself, and time by itself, are doomed to fade away
into mere shadows, and only a kind of union of the two will preserve an
independent reality."
All the best
Ian Macmillan
.
|
|
|
|
| User: "Darkwing \Badass\ theducksmailATyahoo.com" |
|
| Title: Re: Relativity for Nongs |
01 Oct 2005 01:37:16 PM |
|
|
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:zYx%e.379768$x96.180716@attbi_s72...
Ian Macmillan wrote:
Special Relativity is a theory that says that time is intrinsic to
distance, and looks at the consequences where there is no accelleration.
Nothing can be seen to travel any distance without also travelling its
intrinsic time, which is about one nanosecond per foot. No distance can
be travelled in less than this time any more than any distance can be
travelled in less than that distance.
Lightspeed is limited only by the time intrinsic to distance, so that the
speed of light appears as constant. We speak of the "speed of light",
but it is more useful to think "nanoseconds per foot", rather than "feet
per nanosecond".
The principle of Relativity says that, as there is nothing to refer to in
space, motion can only be measured as being relative between bodies.
An inertial frame is a collection of points at mutual rest. All the laws
of nature are the same inside each and every inertial frame.
If inertial frames are in mutual motion, times measured in one frame will
differ from those measured in the other because motion is travel through
time as well as distance.
If relative times differ, so will the intrinsicly related distances.
Imagine a flying clock passing two points on your inertial frame. You can
photograph the clock as it passes each point, and record the time of
passing on your clocks.
The time you measure between the passings is a composition of the time
intrinsic to the distance between the points, and the time between
the passing events as shown by the flying clock.
The flying clock considers itself to be at rest, and registers the events
of two points successively flying past it, a time unaffected by distance.
The relationship between the times is that of a right angled triangle.
The time intrinsic to the distance and the time shown by the flying clock
are taken at right angles, with the transit time between the points
forming the hypotenuse.
The flying clock shows a travel time less than the transit time shown by
your clocks, because as far as it is concerned, it did not travel.
The flying clock did not run slower, it experienced less time.
Given the lesser time seen on the moving frame, and if in light speed
experiments the space-time relationship is to be maintained, lengths
there will also be seen as less in the same proportion as times.
Carefully thinking about how measurements should be made, you will see
that the relativity between moving frames is symmetrical
A bit of simple algebra will convert the time relationship I have
described to the conventional velocity relationships.
All the best
Ian Macmillan
For instance, the length of an object becomes shorter
when it travels at a constant velocity, and a moving
clock runs slower than a stationary clock.
That's not true, I was traveling close to the speed of light and measured my
12" Subway sandwich and it still measured 12" long.
-----------------------------------------------------------
DW
.
|
|
|
| User: "Sam Wormley" |
|
| Title: Re: Relativity for Nongs |
01 Oct 2005 04:49:34 PM |
|
|
Darkwing (Badass) wrote:
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:zYx%e.379768$x96.180716@attbi_s72...
Ian Macmillan wrote:
Special Relativity is a theory that says that time is intrinsic to
distance, and looks at the consequences where there is no accelleration.
Nothing can be seen to travel any distance without also travelling its
intrinsic time, which is about one nanosecond per foot. No distance can
be travelled in less than this time any more than any distance can be
travelled in less than that distance.
Lightspeed is limited only by the time intrinsic to distance, so that the
speed of light appears as constant. We speak of the "speed of light",
but it is more useful to think "nanoseconds per foot", rather than "feet
per nanosecond".
The principle of Relativity says that, as there is nothing to refer to in
space, motion can only be measured as being relative between bodies.
An inertial frame is a collection of points at mutual rest. All the laws
of nature are the same inside each and every inertial frame.
If inertial frames are in mutual motion, times measured in one frame will
differ from those measured in the other because motion is travel through
time as well as distance.
If relative times differ, so will the intrinsicly related distances.
Imagine a flying clock passing two points on your inertial frame. You can
photograph the clock as it passes each point, and record the time of
passing on your clocks.
The time you measure between the passings is a composition of the time
intrinsic to the distance between the points, and the time between
the passing events as shown by the flying clock.
The flying clock considers itself to be at rest, and registers the events
of two points successively flying past it, a time unaffected by distance.
The relationship between the times is that of a right angled triangle.
The time intrinsic to the distance and the time shown by the flying clock
are taken at right angles, with the transit time between the points
forming the hypotenuse.
The flying clock shows a travel time less than the transit time shown by
your clocks, because as far as it is concerned, it did not travel.
The flying clock did not run slower, it experienced less time.
Given the lesser time seen on the moving frame, and if in light speed
experiments the space-time relationship is to be maintained, lengths
there will also be seen as less in the same proportion as times.
Carefully thinking about how measurements should be made, you will see
that the relativity between moving frames is symmetrical
A bit of simple algebra will convert the time relationship I have
described to the conventional velocity relationships.
All the best
Ian Macmillan
For instance, the length of an object becomes shorter
when it travels at a constant velocity, and a moving
clock runs slower than a stationary clock.
That's not true, I was traveling close to the speed of light and measured my
12" Subway sandwich and it still measured 12" long.
-----------------------------------------------------------
DW
That's because there wasn't relativistic velocity between you and
your sub. Better luck next time.
.
|
|
|
| User: "The Ghost In The Machine" |
|
| Title: Re: Relativity for Nongs |
01 Oct 2005 07:00:06 PM |
|
|
In sci.physics, Sam Wormley
<swormley1@mchsi.com>
wrote
on Sat, 01 Oct 2005 21:49:34 GMT
<OvD%e.380258$x96.89921@attbi_s72>:
Darkwing (Badass) wrote:
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:zYx%e.379768$x96.180716@attbi_s72...
[sigsnip]
That's not true, I was traveling close to the speed of
light and measured my 12" Subway sandwich and it still
measured 12" long.
-----------------------------------------------------------
DW
That's because there wasn't relativistic velocity between you and
your sub. Better luck next time.
Did he want a sandwich or a weapon that makes "Fat Man" look
like a firecracker? :-)
Assume a 1 kg hoagie moving at 0.6 c. The kinetic energy
of that hoagie is 22.5 petajoules (this is not including
the rest mass component of 90 petajoules). By contrast,
Fat Man had a yield of 105 terajoules -- and weighed 4545 kg.
I'm not sure how much good ducking will do, or even an atomic
air raid shelter. :-)
--
#191,
It's still legal to go .sigless.
.
|
|
|
| User: "tj Frazir" |
|
| Title: Re: Relativity for Nongs |
01 Oct 2005 11:34:32 PM |
|
|
Ghost is still in shock after seeing a water cooler jug 1/2 water 1/2 35
psi air water rocket fly over a house . 90 pound thrust for 1 sec.
Block the hole with a sliding vane is 90 pound thrust converted to
rotoation .
Ghost dont think a 100 rpm diesel will run .
125 rpm full speed.
ShipExpo.com
Address:http://shipexpo.com/sales/vessel_detail.asp?FileNo=2486
Audio:http://shipexpo.com/_content/sounds/hummer.wav
Check the rpm on this 8000 kw .
125 rpm.
but I use that same stroke but boost it with o2 and use i on a sliding
vane ..
250,000 hp on 10 ton day .
300,000 pounds of thrust .
on 10 ton fuel day .
854 psi
.
|
|
|
|
| User: "Sam Wormley" |
|
| Title: Re: Relativity for Nongs |
01 Oct 2005 07:13:59 PM |
|
|
The Ghost In The Machine wrote:
In sci.physics, Sam Wormley
<swormley1@mchsi.com>
wrote
on Sat, 01 Oct 2005 21:49:34 GMT
<OvD%e.380258$x96.89921@attbi_s72>:
Darkwing (Badass) wrote:
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:zYx%e.379768$x96.180716@attbi_s72...
[sigsnip]
That's not true, I was traveling close to the speed of
light and measured my 12" Subway sandwich and it still
measured 12" long.
-----------------------------------------------------------
DW
That's because there wasn't relativistic velocity between you and
your sub. Better luck next time.
Did he want a sandwich or a weapon that makes "Fat Man" look
like a firecracker? :-)
Assume a 1 kg hoagie moving at 0.6 c. The kinetic energy
of that hoagie is 22.5 petajoules (this is not including
the rest mass component of 90 petajoules). By contrast,
Fat Man had a yield of 105 terajoules -- and weighed 4545 kg.
I'm not sure how much good ducking will do, or even an atomic
air raid shelter. :-)
That's the problem (other than fuel costs) with relativistic
space travel... every grain of sand is catastrophic.... and
coming at any thing close to the speed of light... well the
deflector shields just ain't gonna work!
The standard answer of UFO buffs is that the aliens are more
advanced than we are... they can get around the laws of physics.
.
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| User: "The Ghost In The Machine" |
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| Title: Re: Relativity for Nongs |
02 Oct 2005 01:00:03 AM |
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In sci.physics, Sam Wormley
<swormley1@mchsi.com>
wrote
on Sun, 02 Oct 2005 00:13:59 GMT
<bDF%e.380640$x96.268080@attbi_s72>:
The Ghost In The Machine wrote:
In sci.physics, Sam Wormley
<swormley1@mchsi.com>
wrote
on Sat, 01 Oct 2005 21:49:34 GMT
<OvD%e.380258$x96.89921@attbi_s72>:
Darkwing (Badass) wrote:
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:zYx%e.379768$x96.180716@attbi_s72...
[sigsnip]
That's not true, I was traveling close to the speed of
light and measured my 12" Subway sandwich and it still
measured 12" long.
-----------------------------------------------------------
DW
That's because there wasn't relativistic velocity between you and
your sub. Better luck next time.
Did he want a sandwich or a weapon that makes "Fat Man" look
like a firecracker? :-)
Assume a 1 kg hoagie moving at 0.6 c. The kinetic energy
of that hoagie is 22.5 petajoules (this is not including
the rest mass component of 90 petajoules). By contrast,
Fat Man had a yield of 105 terajoules -- and weighed 4545 kg.
I'm not sure how much good ducking will do, or even an atomic
air raid shelter. :-)
That's the problem (other than fuel costs) with relativistic
space travel... every grain of sand is catastrophic.... and
coming at any thing close to the speed of light... well the
deflector shields just ain't gonna work!
The standard answer of UFO buffs is that the aliens are more
advanced than we are... they can get around the laws of physics.
Ah yes, good subpoint that. Even in Earth orbit a speck of dust
is dangerous.
As for "deflector shields" -- an interesting calculation comes
to mind, the voltage requirement for deflecting protons of a
certain velocity away from the spacecraft.
And then there's the C-ship within the Lattice Galaxy:
http://www.fourmilab.ch/cship/cship.html
The main problem with this craft is lack of a power source, but
it's an interesting idea. If one assumes green at 500 nm,
blue at 400 nm, and red at 625 nm, one can compute a speed of
about 0.2 c.
Fortunately there are no hoagies in space, though there's
plenty of other debris -- about 1 atom per cubic meter,
if I'm not mistaken. At 0.6 c a spacecraft the size of
the Starship Enterprise, with length 288.646 m (how they
get that accurate with armor plating is far from clear),
width 127.102 m, height 72.6 m, maybe 30% or so of the
front-section of the craft is effectively human-inhabited
and hitting the particles, judging from a very quickie
look at these 1973-era blueprints -- assuming it is
moving forward, which gets the gravity wrong -- one gets
an irradiated cross section of 2768 m^2, and for every
m^2 of that section the front edge of the craft will hit
0.6 * 3 * 10^8 m/s * 1 * 1.25 at/m^3 atoms per second,
with each atom, assuming hydrogen, imparting an energy of
about 1172.5 MeV each. This translates to a raw power of
about 42 milliwatts per square meter.
How that translates into rems or seiferts, I don't know. Not too
bad at that speed but at .96c one gets more than half a watt;
as one approaches 1.000c the radiation becomes infinite.
Anyone for fried redshirt? :-)
It gets worse within the star system; the density jumps up to
about 6 atoms per cubic *centimeter*; at 0.6 c the spacecraft
gets a rather toasty 252 kW/m^2. Better slow 'er down,
Mr. Scott; we don't want Yeoman Rand and Nurse Chapel (not
to mention all the other crewmembers) to get *that* hot. :-)
The good news is that Captain Kirk preferred chicken sandwiches
and soup, at least in one episode. (The bad news: it wouldn't
make that much difference.)
--
#191,
It's still legal to go .sigless.
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