Opportunity knocks when you're already in the Spirit...

Andrew Gray ) wrote:
: In article , Henry Spencer wrote:
: In article ,
: Andrew Gray wrote:
: Greenwich runs through, IIRC, the site of the Royal Observatory, which
: makes pretty good sense g
:
: If you're British, that is. :-)

: Wait, you don't all recognise that South London is the centre of the
: universe?

Geez, it's "recognize", "center" and "the Universe." Andy, with mistakes
like that with the English Language, its no wonder that Britain has failed
to qualify as the 51st state!

Eric

John Schutkeker ) wrote:
: "Greg D. Moore \(Strider\)" wrote in
: :

: I'm not sure the Sun or any of the gas giants really do simply because of
: the lack of fixed surface features.

: Apparently Jupiter's solid core has some fixed features, which are
: observable as radio emissions. It sounds like a standard in flux, though.

: http://voyager.ftecs.com/sedr/overview.html

In the case of Jupiter start with the Red Spot and work from there.

Eric

(Eric Chomko) wrote in
:

In the case of Jupiter start with the Red Spot and work from there.

I'm not up on the physics, but it might be that the red spot drifts around
the planet. Although that was my original idea, it is a gaseous body,
after all.

Check out Venus, which is tidally locked to the Earth! At every closest
approach, it presents the same face to us. Isn't that outrageous? Because
of that, I'd expect it's prime meridian to be defined similarly as the
moon's.

In article ,
John Schutkeker wrote:
Check out Venus, which is tidally locked to the Earth! At every closest
approach, it presents the same face to us.

Nope, not quite. Very nearly so, but not exactly. So in fact, it is
*not* tidally locked. Which is unsurprising, since Earth's tidal forces
on Venus are minute.

...I'd expect it's prime meridian to be defined similarly as the
moon's.

It's not.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

John Schutkeker wrote in
3:

I'm not up on the physics, but it might be that the red spot drifts
around the planet. Although that was my original idea, it is a
gaseous body, after all.

Check out Venus, which is tidally locked to the Earth! At every
closest approach, it presents the same face to us. Isn't that
outrageous? Because of that, I'd expect it's prime meridian to be
defined similarly as the moon's.

Your entire posting has one correct fact in it. The part where you say I'm
not up on the physics"

As for the rest... What are you smoking and WHY are you not sharing it?

(Henry Spencer) wrote in :

Check out Venus, which is tidally locked to the Earth! At every closest
approach, it presents the same face to us.

Nope, not quite. Very nearly so, but not exactly. So in fact, it is
*not* tidally locked. Which is unsurprising, since Earth's tidal forces
on Venus are minute.

Then what causes the synchronization?

In article ,
John Schutkeker wrote:
Nope, not quite. Very nearly so, but not exactly. So in fact, it is
*not* tidally locked. Which is unsurprising, since Earth's tidal forces
on Venus are minute.

Then what causes the synchronization?

The *approximate* synchronization is thought to be an accident. It's hard
to make any other explanation work.

One speculation is that the dynamics of the atmospheric super-rotation
(much of Venus's *atmosphere* goes around Venus about every four Earth
days) tend to exert a retrograde torque (in a direction opposite to the
orbital motion) on the planet, but that this becomes very weak once the
planet's rotation rate reaches zero... which would lead you to expect a
very slow retrograde rotation, just what Venus has. That would naturally
put its rotation in the right ballpark for an approximate synchronization
with Earth, making the apparent coincidence much less striking.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

John Schutkeker ) wrote:
: (Eric Chomko) wrote in
: :

: In the case of Jupiter start with the Red Spot and work from there.

: I'm not up on the physics, but it might be that the red spot drifts around
: the planet. Although that was my original idea, it is a gaseous body,
: after all.

Yeah, the Red Spot does drift. But I think observationally you can't see
the suface of Jupiter.

: Check out Venus, which is tidally locked to the Earth! At every closest
: approach, it presents the same face to us. Isn't that outrageous? Because
: of that, I'd expect it's prime meridian to be defined similarly as the
: moon's.

I thought Venus had a synodic period (time between oppositions of Earth
and Venus) 584 days and a rotation period (retrograde) of 243 days (it's
day is longer than its year, at 224.7 days)? The relationship between 584
and 243 is not a whole number (2.4). Therefore, Venus can't be tidal
locked to the Earth.

Eric

Peter Harding ) wrote:
: In article ,
: says...
: Geez, it's "recognize",

: Correct.

: "center"

: Either is correct.

: and "the Universe."

: Wrong.

What is the proper name for the universe?

: Andy, with mistakes
: like that with the English Language, its no wonder that Britain has failed
: to qualify as the 51st state!

: That should be "it's".

Yes, yes, and I stole the "qualify for the 51st state" joke, too. But is
is still a good one.

Eric

: --
: ICQ 40628243 Tel 07092057581 Fax 07092308800

Henry Spencer ) wrote:
: In article ,
: John Schutkeker wrote:
: Check out Venus, which is tidally locked to the Earth! At every closest
: approach, it presents the same face to us.

: Nope, not quite. Very nearly so, but not exactly. So in fact, it is
: *not* tidally locked. Which is unsurprising, since Earth's tidal forces
: on Venus are minute.

Synodic period of 584 days and a rotation period of 243 days. How can that
add up to presenting the same face to Earth?

Eric

: ...I'd expect it's prime meridian to be defined similarly as the
: moon's.

: It's not.
: --
: MOST launched 30 June; science observations running | Henry Spencer
: since Oct; first surprises seen; papers pending. |