APOD: Jupiter and Io (2012 Nov 28)

Comments and questions about the APOD on the main view screen.

APOD: Jupiter and Io (2012 Nov 28)

Postby APOD Robot » Wed Nov 28, 2012 5:06 am

Image Jupiter and Io

Explanation: On December 3 (UT), Jupiter, the solar system's largest planet, will be at opposition, opposite the Sun in planet Earth's sky, shining brightly and rising as the Sun sets. That configuration results in Jupiter's almost annual closest approach to planet Earth. So, near opposition the gas giant offers earthbound telescopes stunning views of its stormy, banded atmosphere and large Galilean moons. For example, this sharp series was recorded on the night of November 16/17 from the island of Sardinia near Dolianova, Italy. North is up in the images that show off Jupiter's famous Great Red Spot, and planet girdling dark belts and light zones. Also seen in transit is Jupiter's volcanic moon Io, its round, dark shadow tracking across the Jovian cloud tops as the sequence progresses left to right.

<< Previous APOD This Day in APOD Next APOD >>
User avatar
APOD Robot
Otto Posterman
 
Posts: 1712
Joined: Fri Dec 04, 2009 3:27 am

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby A.A. Verveen » Wed Nov 28, 2012 8:52 am

Nice squinted-eye "3D pictures" of Jupiter, and and also of Jupiter and Io!
A.A. Verveen
 

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby PhilT » Wed Nov 28, 2012 9:41 am

Hi,
I've experienced an eclipse once here on Earth and there was a noticeable temperature drop (surprise, surprise :ssmile: ).

Could the shadowing effect of IO affect the storms on Jupiter and explain why we see bands of storms ?

Just a thought/Phil
PhilT
 

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby 5jdw28 » Wed Nov 28, 2012 11:03 am

The Earth, with its shorter orbit, approaches Jupiter each year, NOT the other way around!!!
Try for some ACCURACY, PLEASE.
It is annoying to constantly find errors of fact, grammar, and spelling at this site.
And you actually have TWO editors who aren't doing their jobs!
5jdw28
 

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby owlice » Wed Nov 28, 2012 11:08 am

If the site annoys you, perhaps you ought not to be looking at it.

~~~~~~~~~~~~~~~~~~~

I cannot help but think of this little bit of verse when seeing an image of Jupiter and Io: http://www.baltastro.org/AstroPoetry.html#JupiterAndTen

:-D
A closed mouth gathers no foot.
User avatar
owlice
Guardian of the Codes
 
Posts: 7873
Joined: Wed Aug 04, 2004 4:18 pm
Location: Washington, DC

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby JohnD » Wed Nov 28, 2012 11:55 am

If Jupiter is at opposition, and the images of it confirm that - no shadowed area on the gas surface, why is the shadow of Io so displaced to the right?
Even when Io approaches the centre of Jupiter's disc, the shadow is significantly displaced, when I would expect it to almost coincide.

John
User avatar
JohnD
Tea Time, Guv! Cheerio!
 
Posts: 682
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby Markus Schwarz » Wed Nov 28, 2012 11:57 am

5jdw28 wrote:The Earth, with its shorter orbit, approaches Jupiter each year, NOT the other way around!!!
Try for some ACCURACY, PLEASE.

Dear 5djw28,
since English is not my native language, I looked up the meaning of approach at Merriam-Webster. I find the following two examples helpful:
- The cat approached the baby cautiously.
- Ease off the gas pedal to slow down as the bend in the road approaches.
In the first example the cat actively closes the distance to the baby, and the situation is viewed by a third observer. In the second example, the situation is viewed from inside a vehicle, say a car. Clearly, the bend in the road is not approaching the car actively. An observer on the side of the road would say that the car approaches the bend.
IMHO, the situation is the same for Earth and Jupiter. You take the position of an outside observer, who sits at the center of gravity of the solar system. Earthlings that they are, the APOD editors seem to take the second point of view. From my linguistic understandings, both are correct statements.
From a physics point of view, keep in mind that you can solve the equations of motion for the planets in any coordinate system you like. In practice, they are most easily solved if you take the center of gravity as the origin. But besides mathematical complexity, nothing prevents you from solving them taking Earth as your origin.
Markus Schwarz
Ensign
 
Posts: 85
Joined: Wed Apr 29, 2009 11:55 am
Location: Germany

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby soulfly66 » Wed Nov 28, 2012 1:28 pm

Hi i'm Wolfgang F. from Austria greetings to all here on this site.
What a splendid page Astronomy picture of the Day Thank you sooooooo much enjoy it every Day!!!! :D
soulfly66
 

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby ber.droid » Wed Nov 28, 2012 1:37 pm

JohnD wrote:If Jupiter is at opposition, and the images of it confirm that - no shadowed area on the gas surface, why is the shadow of Io so displaced to the right?
Even when Io approaches the centre of Jupiter's disc, the shadow is significantly displaced, when I would expect it to almost coincide.


I was immediately wondering at this, too!

Ber
ber.droid
 

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby FloridaMike » Wed Nov 28, 2012 2:18 pm

ber.droid wrote:
JohnD wrote:If Jupiter is at opposition, and the images of it confirm that - no shadowed area on the gas surface, why is the shadow of Io so displaced to the right?
Even when Io approaches the centre of Jupiter's disc, the shadow is significantly displaced, when I would expect it to almost coincide.


I was immediately wondering at this, too!

Ber


I "third" this question.
Certainty is an emotion.
FloridaMike
Science Officer
 
Posts: 151
Joined: Fri Nov 04, 2011 2:21 pm
Location: Florida, USA

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby neufer » Wed Nov 28, 2012 2:20 pm

ber.droid wrote:
JohnD wrote:
If Jupiter is at opposition, and the images of it confirm that -
no shadowed area on the gas surface, why is the shadow of Io so displaced to the right?

Even when Io approaches the centre of Jupiter's disc, the shadow is significantly displaced, when I would expect it to almost coincide.

I was immediately wondering at this, too!

    1) The picture was taken over a fortnight before opposition.

    2) Io orbits almost 5 Jupiter radii above Jupiter's surface
    . thereby exaggerating the solar surface shadow displacement (as viewed from Earth) by a factor of ~5.
APOD Robot wrote:Image Jupiter and Io

On December 3 (UT), Jupiter will be at opposition,
this sharp series was recorded on the night of November 16/17

http://space.jpl.nasa.gov/cgi-bin/wspac ... 1&showac=1
http://space.jpl.nasa.gov/cgi-bin/wspac ... 1&showac=1
Art Neuendorffer
User avatar
neufer
Abstruse Allusion Artificer
 
Posts: 11395
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby moonstruck » Wed Nov 28, 2012 2:34 pm

hi io
moonstruck
Science Officer
 
Posts: 164
Joined: Fri Jun 18, 2010 2:27 pm

Oh, "hi io."

Postby neufer » Wed Nov 28, 2012 2:52 pm

Click to play embedded YouTube video.
moonstruck wrote:
    hi io
Chris Peterson wrote:
I know of nothing about the Universe that precludes teleportation, but the Universe seems quite adamant about its restriction on conveying information faster than light. So this thought experiment becomes just another variation on "what if we could travel faster than light", replete with the same paradoxes and causality variations. Amusing, but with no basis in reality.
Art Neuendorffer
User avatar
neufer
Abstruse Allusion Artificer
 
Posts: 11395
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby Gary E. Johnson » Wed Nov 28, 2012 4:00 pm

If Jupiter and Sol are at opposition in Earth's sky, then the sun's rays passing earth go directly to Jupiter. Why is it that we can see the shadow of Io on Jupiter's surface? Shouldn't that shadow be directly behind the moon?
Gary E. Johnson
 

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby Gary again » Wed Nov 28, 2012 4:04 pm

Gary E. Johnson wrote:If Jupiter and Sol are at opposition in Earth's sky, then the sun's rays passing earth go directly to Jupiter. Why is it that we can see the shadow of Io on Jupiter's surface? Shouldn't that shadow be directly behind the moon?

Guess I should read all posts before posting -- a good expanation was already provided. Thanks and cheers!
Gary again
 

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby Ann » Wed Nov 28, 2012 4:13 pm

owlice wrote:I cannot help but think of this little bit of verse when seeing an image of Jupiter and Io: http://www.baltastro.org/AstroPoetry.html#JupiterAndTen

:-D


I agree. "Jupiter and Ten" sounds considerably more frustratingly fascinating than "Jupiter and Io" (Jupiter and IO?)

Ann
Color Commentator
User avatar
Ann
4725 Å
 
Posts: 5403
Joined: Sat May 29, 2010 5:33 am

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby FloridaMike » Wed Nov 28, 2012 4:54 pm

neufer wrote:
    1) The picture was taken over a fortnight before opposition.

    2) Io orbits almost 5 Jupiter radii above Jupiter's surface
    . thereby exaggerating the solar surface shadow displacement (as viewed from Earth) by a factor of ~5.


Ahhh, I was thinking of the angular change in Jupiter's position over a "fortnight" and neglecting the angular change of the earth. Thanks!
Certainty is an emotion.
FloridaMike
Science Officer
 
Posts: 151
Joined: Fri Nov 04, 2011 2:21 pm
Location: Florida, USA

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby JohnD » Wed Nov 28, 2012 5:23 pm

neufer,
I can't square your answer with geometry. The distance of Io from Jupiter is irrelevant.

At the orbit of Jupiter, the Sun's rays are as near to parallel as dammit.
So the distance Io moves daily in its orbit is the same as the distance moved on the 'surface' of Jupiter, increased as the shadow moves away from directly under the Sun, and decreased as the shadow moves from the limb of Jupiter towards its centre, by the Tangent of the angle of the sun above the horizon.

That difference would not be visible from Earth at opposition, when we are looking along the Sun's rays, although it should be if we could see Jupiter 'from the side', with an obvious terminator. Do we ever see it that way, except from Galileo?

I'll gladly accept your point about the pictures being taken some time before true opposition. If the angle of the Sun was so great in relation to the angle of view from Earth that Io's shadow is so displaced, should we not see the terminator at the edge of Jupiter's disc, peeping around it by a similar amount?
John
User avatar
JohnD
Tea Time, Guv! Cheerio!
 
Posts: 682
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby neufer » Wed Nov 28, 2012 5:49 pm

JohnD wrote:
neufer, I can't square your answer with geometry. The distance of Io from Jupiter is irrelevant.

At the orbit of Jupiter, the Sun's rays are as near to parallel as dammit.
So the distance Io moves daily in its orbit is the same as the distance moved on the 'surface' of Jupiter, increased as the shadow moves away from directly under the Sun, and decreased as the shadow moves from the limb of Jupiter towards its centre, by the Tangent of the angle of the sun above the horizon.

Unless you know differently.

I do know differently, John. Differently is a friend of mine.

If Io was lying on the surface of Jupiter its shadow would be directly under it
as viewed from Earth (~ 3.6º off the Sun-Jupiter axis).
http://space.jpl.nasa.gov/cgi-bin/wspac ... 1&showac=1

If Io was just one Jupiter radius above the surface of Jupiter
its shadow would be ~ 3.6º east longitude on Jupiter as viewed from Earth (~ 3.6º off the Sun-Jupiter axis).

Since Io is ~ 5 Jupiter radii above the surface of Jupiter
its shadow is ~ 18º east longitude on Jupiter as viewed from Earth (~ 3.6º off the Sun-Jupiter axis).
Last edited by neufer on Wed Nov 28, 2012 5:53 pm, edited 1 time in total.
Art Neuendorffer
User avatar
neufer
Abstruse Allusion Artificer
 
Posts: 11395
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby mtilley » Wed Nov 28, 2012 5:52 pm

I'm curious about the temporal spacing of these pictures, given Jupiter's rotation rate and IO's orbital period.

Can anyone clarify?
mtilley
 

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby neufer » Wed Nov 28, 2012 6:02 pm

mtilley wrote:
I'm curious about the temporal spacing of these pictures, given Jupiter's rotation rate and IO's orbital period.

Can anyone clarify?

~Every half hour on average?

http://space.jpl.nasa.gov/cgi-bin/wspac ... 1&showac=1

http://space.jpl.nasa.gov/cgi-bin/wspac ... 1&showac=1
Art Neuendorffer
User avatar
neufer
Abstruse Allusion Artificer
 
Posts: 11395
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby Anthony Barreiro » Wed Nov 28, 2012 6:29 pm

Regarding the displacement between Io and Io's shadow on Jupiter's cloud tops, you also need to remember that Io and Jupiter's other moons orbit Jupiter's equator. While Jupiter's equator is only inclined three degrees relative to the plane of it's orbit around the Sun, this angle is enough to affect what we see from here on Earth as we look at Jupiter from along the ecliptic plane. In addition to the east-west displacement (and shadow eclipses) seen before and after opposition, we will also see the moons casting shadows to the south of the equator during Jupiter's northern hemisphere summer (as currently) and to the north during Jupiter's northern hemisphere winter in six years. At Jupiter's equinoxes the shadows will pass right over the equator and a moon will pass directly over its shadow at mid-transit. Jupiter's next equinox will happen in 2015.

Near Jupiter's northern winter solstice, as currently, Ganymede passes high behind Jupiter's northern limb and low in front of the southern limb. More distant Callisto passes above and below the disk of Jupiter as seen from Earth.

And regarding whether Jupiter is approaching us or we are approaching Jupiter, I believe the answer is "yes."

This a lovely series of images, by the way, thank you Alessandro!

Anybody with a telescope of any size and a clear sky should be observing Jupiter and his moons these nights. While you may not see the level of detail in Alessandro's pictures, you will see the cloud bands, and you can watch the moons in their graceful orbital dance and strive to understand what Galileo figured out using a crude one-inch refractor.
May all beings be happy, peaceful, and free.
User avatar
Anthony Barreiro
Commander
 
Posts: 758
Joined: Wed May 11, 2011 7:09 pm
Location: San Francisco, California, Turtle Island

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby bystander » Wed Nov 28, 2012 8:20 pm

neufer wrote:
JohnD wrote:Unless you know differently.

I do know differently, John. Differently is a friend of mine.

I thought you were differently. There's another like you?
I don't imagine you will dispute the fact that at present the stupid people
are in an absolutely overwhelming majority all the world over.
— Henrik Ibsen
User avatar
bystander
Apathetic Retiree
 
Posts: 11942
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby neufer » Wed Nov 28, 2012 9:44 pm

bystander wrote:
neufer wrote:
JohnD wrote:
Unless you know differently.

I do know differently, John. Differently is a friend of mine.

I thought you were differently. There's another like you?

I'm definitely diffidently not differently.
Art Neuendorffer
User avatar
neufer
Abstruse Allusion Artificer
 
Posts: 11395
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Jupiter and Io (2012 Nov 28)

Postby Boomer12k » Wed Nov 28, 2012 10:38 pm

"Dance of the Planets", round and round ad infinitum.

:---[===] *
Boomer12k
:---[===] *
 
Posts: 920
Joined: Sun Apr 22, 2007 12:07 am

Next

Return to The Bridge: Discuss an Astronomy Picture of the Day

Who is online

Users browsing this forum: Bing [Bot], CommonCrawl [Bot], Exalead [Bot], Google Mobile [Bot], MSNbot Media and 11 guests