Astronomical unit gets redefined

Astronomical unit gets redefined
http://blogs.physicstoday.org/newspi...ets-redefined/

A vote at a meeting of the International Astronomical Union has redefined the astronomical unit, the au, as exactly 149 597 870 700 meters.

The new, noncalculated value makes the unit much easier to explain to students, and no longer varies because of general relativity or the decreasing mass of the Sun.

On Friday, September 14, 2012 1:58:55 PM UTC-4, Sam Wormley wrote:
Astronomical unit gets redefined

http://blogs.physicstoday.org/newspi...ets-redefined/



A vote at a meeting of the International Astronomical Union has redefined the astronomical unit, the au, as exactly 149 597 870 700 meters.



The new, noncalculated value makes the unit much easier to explain to students, and no longer varies because of general relativity or the decreasing mass of the Sun.

Interesting, thanks for the "heads up".

On Sep 14, 7:58*pm, Sam Wormley wrote:
Astronomical unit gets redefined







http://blogs.physicstoday.org/newspi...mical-unit-get...
A vote at a meeting of the International Astronomical Union has redefined the astronomical unit, the au, as exactly 149 597 870 700 meters.
The new, noncalculated value makes the unit much easier to explain to students, and no longer varies because of general relativity or the decreasing mass of the Sun.

I often wonder what the great astronomers did to deserve having their
works mangled and even if there is a problem with Kepler's correlation
between orbital periods and distance from the Sun using a measuring
standard that is not fixed with one orbital period,not even the
Earth's distance from the Sun,and has nothing to do with the size of
the Sun or anything else.The fact is that it is exceptionally easy to
explain Kepler's correlation to students once you understand the
proper resolution for retrogrades is included for both planets but
contemporaries can't even do that properly .

The formal statement of Kepler can be daunting at first sight to those
who are unfamiliar with the method by which observations from a moving
Earth are transformed into models of planetary dynamics and solar
system structure -

"The proportion existing between the periodic times of any two planets
is exactly the sesquiplicate proportion of the mean distances of the
orbits, or as generally given,the squares of the periodic times are
proportional to the cubes of the mean distances." Kepler

The expansion of this statement to terms students can understand is
otherwise and fairly easy and straightforward -

"But it is absolutely certain and exact that the ratio which exists
between the periodic times of any two planets is precisely the ratio
of the 3/2th power of the mean distances, i.e., of the spheres
themselves; provided, however, that the arithmetic mean between both
diameters of the elliptic orbit be slightly less than the longer
diameter. And so if any one take the period, say, of the Earth, which
is one year, and the period of Saturn, which is thirty years, and
extract the cube roots of this ratio and then square the ensuing ratio
by squaring the cube roots, he will have as his numerical products the
most just ratio of the distances of the Earth and Saturn from the sun.
1 For the cube root of 1 is 1, and the square of it is 1; and the cube
root of 30 is greater than 3, and therefore the square of it is
greater than 9. And Saturn, at its mean distance from the sun, is
slightly higher than nine times the mean distance of the Earth from
the sun." Kepler

These nuisances in the IAU are trying to gain some sort of authority
by making things worse and I suggest readers who are into genuine
astronomy simply take the few steps needed to make sense of Kepler's
attempt to turn a time coordinate ( annual periodic times) into a
geometric trait (distance from the Sun).Simply use Mars as a gauge
against the motion of the Earth to arrive at a clear understanding of
what Kepler was actually doing and it has nothing to do with vague
references to solar mass,it is simply an observational ideology

http://upload.wikimedia.org/wikipedi...retrograde.jpg

"Copernicus, by attributing a single annual motion to the earth,
entirely rids the planets of these extremely intricate coils, leading
the individual planets into their respective orbits ,quite bare and
very nearly circular. In the period of time shown in the diagram, Mars
traverses one and the same orbit as many times as the 'garlands' you
see looped towards the centre,with one extra, making nine times, while
at the same time the Earth repeats its circle sixteen times "
Astronomia Nova 1609 Kepler

This standard of astronomy is lovely once you see what Kepler looked
at and indeed modern imaging supplies the exact same thing in a 21st
century format as the old 'Panis Quadragesimalis' of Kepler

http://apod.nasa.gov/apod/ap120809.html

Before anyone goes to define or redefine something,let them come here
to this forum and deal with genuine astronomy and nothing dithering
around with words.

On Sep 14, 11:58*am, Sam Wormley wrote:

A vote at a meeting of the International Astronomical Union has redefined the astronomical unit, the au, as exactly 149 597 870 700 meters.

I suppose that after the speed of light got redefined, this was only a
matter of time. Actually, that wasn't fair: the speed of light
_didn't_ get redefined; it's still the actual speed at which light
travels in a vacuum, and so it didn't get treated as roughly as the
mean semi-major axis of the Earth's orbit... it was the *second* that
was redefined.

Fortunately, though, history did not repeat itself. Had the IAU
redefined the metre (which, of course, they had no authority to do,
not being the custodians of that unit) as 1/149,597,870,700 of the
mean semi-major axis of the Earth's orbit, the precision with which
the metre could be determined would have taken a sharp turn downwards,
and the difficulty of determining it would have taken a sharp turn
upwards.

John Savard

Sam Wormley wrote:
Astronomical unit gets redefined

http://blogs.physicstoday.org/newspi...-unit-gets-red
efined/

A vote at a meeting of the International Astronomical Union has redefined
the astronomical unit, the au, as exactly 149 597 870 700 meters.

The new, noncalculated value makes the unit much easier to explain to
students, and no longer varies because of general relativity or the
decreasing mass of the Sun.

That's all well and good. Did they also vote on emphasizing the fact
that the astronomical unit is not a planet?

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

"Quadibloc" wrote in message ...
it's still the actual speed at which light
travels in a vacuum, and so it didn't get treated as roughly as the
mean semi-major axis of the Earth's orbit... it was the *second* that
was redefined.

You are an insane moron, Quadiblockhead, and full of ****.
http://physics.nist.gov/cuu/Units/meter.html
http://physics.nist.gov/cuu/Units/second.html

You obviously have no idea what you are babbling about.
-- This message is brought to you from the keyboard of
Lord Androcles, Zeroth Earl of Medway

On Sep 14, 6:56*pm, "Lord Androcles, Zeroth Earl of Medway"
wrote:

You obviously have no idea what you are babbling about.

Oops. So they redefined the meter and kept the second the same, not
the other way around; which I once knew

http://www.quadibloc.com/other/cnv03.htm

but got wrong off the top of my head for a USENET post.

John Savard

"Quadibloc" wrote in message ...
On Sep 14, 6:56 pm, "Lord Androcles, Zeroth Earl of Medway"
wrote:

You obviously have no idea what you are babbling about.

Oops. So they redefined the meter and kept the second the same, not
the other way around; which I once knew

http://www.quadibloc.com/other/cnv03.htm


but got wrong off the top of my head for a USENET post.

John Savard


==============================================
Who is A. A. Michaelson?
You got that wrong too.
http://phys.org/news204470740.html

If time at altitude differs from time at sea level then the speed of light
at altitude differs from the speed of light at sea level. Hence the metre
also is a function of altitude.
NIST have no idea what they are babbling about.
I’ll use an ordinary tape measure for my metre and “they� need
locking away in the looney bin, along with the pop science magazine
editors that report their ignorant crap.

-- This message is brought to you from the keyboard of
Lord Androcles, Zeroth Earl of Medway

On Friday, September 14, 2012 10:58:55 AM UTC-7, Sam Wormley wrote:
Astronomical unit gets redefined

http://blogs.physicstoday.org/newspi...ets-redefined/



A vote at a meeting of the International Astronomical Union has redefined the astronomical unit, the au, as exactly 149 597 870 700 meters.



The new, noncalculated value makes the unit much easier to explain to students, and no longer varies because of general relativity or the decreasing mass of the Sun.

As always, thanks, Sam!!!

In article , swormley1
@gmail.com says...

Astronomical unit gets redefined
http://blogs.physicstoday.org/newspi...ets-redefined/

A vote at a meeting of the International Astronomical Union has
redefined the astronomical unit, the au, as exactly 149 597 870 700
meters.

The new, noncalculated value makes the unit much easier to explain
to students, and no longer varies because of general relativity or
the decreasing mass of the Sun.

Interesting! But that means that the Gaussian gravitational constant k
will no longer be strictly constant.