APOD: Jupiter Marble from Juno (2019 May 08)

[APOD Robot]

Jupiter Marble from Juno

Explanation: What does Jupiter look like up close? Most images of Jupiter are taken from far away, either from Earth or from a great enough distance that nearly half the planet is visible. This shot, though, was composed from images taken relatively close in, where less than half of the planet was visible. From here, Jupiter still appears spherical but perspective distortion now makes it look more like a marble. Visible on Jupiter's cloud tops are a prominent dark horizontal belt containing a white oval cloud, and a white zone cloud, both of which circle the planet. The Great Red Spot looms on the upper right. The featured image was taken by the robotic Juno spacecraft in February during its 17th close pass of our Solar System's largest planet. Juno's mission, now extended into 2021, is to study Jupiter in new ways. Juno's data has already enabled discoveries that include Jupiter's magnetic field being surprisingly lumpy, and that some of Jupiter's cloud systems run about 3,000 kilometers into the planet.

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[Ann]

They say that the Great Red Spot is shrinking, but in this picture is looks very large and almost impossibly orange. And very round, too - or, from this perspective, very elongated. And with a little orange "spiral arm" sticking out to the left. (And a tiny little armlet at right too, I think.)

Ann

[Boomer12k]

Notice near the middle, a small orange dot area.... do you think it could be the beginning of a NEW Giant Red Spot?

Awesome Image...

:---[===} *

[neufer]

The red curve is an epicycloid traced as the small circle (radius r = 1) rolls around the outside of the large circle (radius R = 3).

---

Notice near the middle, a small orange dot area.... do you think it could be the beginning of a NEW Giant Red Spot?

Equatorial rotation velocity: 12.6 km/s

Average orbital speed: 13.07 km/s

Orbital period: 10,476 Jovian solar days

In geometry, an epicycloid or hypercycloid is a plane curve produced by tracing the path of a chosen point on the circumference of a circle—called an epicycle—which rolls without slipping around a fixed circle. It is a particular kind of roulette.

[orin stepanek]

Jupiter would make a very beautiful marble! I don't think it would fit in my bag of immies though!

[neufer]

Jupiter would make a very beautiful marble! I don't think it would fit in my bag of immies though!

Your immies are just immitation Aggies.

[My own "Juno" is a real (very beautiful) New Mexico State University Aggie.]

(non-NMSU) Aggie

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Agates or Aggies - By the middle of the nineteenth century, marbles made of agate had become so popular that the word aggie, a nickname for agate, came to be used for all stone marbles. Many were quarried and ground in Germany and then exported to America and other countries. Aggies were often colored with black, gray, green, blue and yellow mineral dyes.

Immies - glass marbles streaked with color so they look as if they were made of real aggate. Immie is short for immitation.

[Ann]

Jupiter would make a very beautiful marble! I don't think it would fit in my bag of immies though!

Your immies are just immitation Aggies.

[My own "Juno" is a real (very beautiful) New Mexico State University Aggie.]

(non-NMSU) Aggie

---

Agates or Aggies - By the middle of the nineteenth century, marbles made of agate had become so popular that the word aggie, a nickname for agate, came to be used for all stone marbles. Many were quarried and ground in Germany and then exported to America and other countries. Aggies were often colored with black, gray, green, blue and yellow mineral dyes.

Immies - glass marbles streaked with color so they look as if they were made of real aggate. Immie is short for immitation.

Click to view full size image

I have a very beautiful little agate "sculpture" at home. What color is it? Can you guess?

Ann

[geoffrey.landis]

They say that the Great Red Spot is shrinking, but in this picture is looks very large

Yes, that is the "perspective distortion" briefly mentioned in the caption. It's a fisheye lens effect, basically. We're looking at a nearly flat surface from close up. The apparent spherical shape of the planet is mostly the distortion.

and almost impossibly orange.

Probably enhanced color,-- text doesn't discuss that.
That's one of the things I wish every APOD had, a discussion of what the colors are. JunoCam has visible (red/green/blue) filters, so it's probably actually visible (not false color).

[orin stepanek]

Jupiter would make a very beautiful marble! I don't think it would fit in my bag of immies though!

Your immies are just immitation Aggies.

[My own "Juno" is a real (very beautiful) New Mexico State University Aggie.]

(non-NMSU) Aggie

---

Agates or Aggies - By the middle of the nineteenth century, marbles made of agate had become so popular that the word aggie, a nickname for agate, came to be used for all stone marbles. Many were quarried and ground in Germany and then exported to America and other countries. Aggies were often colored with black, gray, green, blue and yellow mineral dyes.

Immies - glass marbles streaked with color so they look as if they were made of real aggate. Immie is short for immitation.

Yeah; My mibs were mostly immies! I did have a few steelies; but those were hard to get! I did have a large steely that I used as my bolder!(shooter) I don't recall having any aggies; but I did have a few solid glass ones! the clear colored ones were prettier though! We mostly played shoot to the pot!

[Chris Peterson]

They say that the Great Red Spot is shrinking, but in this picture is looks very large

Yes, that is the "perspective distortion" briefly mentioned in the caption. It's a fisheye lens effect, basically. We're looking at a nearly flat surface from close up. The apparent spherical shape of the planet is mostly the distortion.

Perspective distortion is not the same as fisheye distortion. The shape we're seeing here isn't an apparently spherical object, it's an actual spherical object, and it will always look the same through any lens, from any distance- like a circle. All that changes with distance is the amount of an entire hemisphere that we can see. This image was made by stitching together narrow field images, and it's unclear what actual optical distortion is present.

[sillyworm 2]

I'm very thankful that I am still alive to view these stunning images and enjoy these remarkable achievements.

[mjsakers]

This is actually pretty interesting. From far away, Jupiter looks like this:

https://apod.nasa.gov/apod/image/1804/J ... z_1880.jpg

But if you got real close, the "horizontal lines" would appear to be bending up or down at the outer edges. But you could never photograph this because you'd be too close to get the whole thing in your frame. So it's almost like, the "marble" image is what Jupiter WOULD look like if it were a much smaller-sized planet AND you were real close and could photograph the whole thing?

[Chris Peterson]

This is actually pretty interesting. From far away, Jupiter looks like this:

https://apod.nasa.gov/apod/image/1804/J ... z_1880.jpg

But if you got real close, the "horizontal lines" would appear to be bending up or down at the outer edges. But you could never photograph this because you'd be too close to get the whole thing in your frame. So it's almost like, the "marble" image is what Jupiter WOULD look like if it were a much smaller-sized planet AND you were real close and could photograph the whole thing?

When you are infinitely far from a sphere, your horizon is defined by the great circle parallel to your view axis. That is, you see an entire hemisphere. As you get closer, your horizon ceases to be defined by a great circle; you see less and less of the hemisphere facing you. This continues until you are on the ground, when your horizon is defined by only a tiny slice of the hemisphere. You can always capture this on a camera, but the field of view of the lens must continue to increase as you get closer to the surface.

We see exactly this same effect in images made from the ISS. Although the Earth looks round, and our brains try to interpret what we're seeing as half of a sphere, we are only seeing a small part of the hemisphere facing the imager. Most of it is below the horizon, just as in today's image of Jupiter from low orbit.

[MarkBour]

I have a very beautiful little agate "sculpture" at home. What color is it? Can you guess?

Ann

I haven't a clue!
And congratulations, Ann. I note that the count of your posts has just recently passed 2 x 4725 .

[neufer]

When you are infinitely far from a sphere, your horizon is defined by the great circle parallel to your view axis. That is, you see an entire hemisphere. As you get closer, your horizon ceases to be defined by a great circle; you see less and less of the hemisphere facing you.

I.e, if you are at a distance D above the North Pole of a sphere of radius R,
your horizon is defined by the circle of latitude = arcsin[R/(R+D)]

If the ISS was above the North Pole it's horizon would be the 70th parallel (= arcsin[6371/(6371+409)]).

[Ann]

I have a very beautiful little agate "sculpture" at home. What color is it? Can you guess?

Ann

I haven't a clue!
And congratulations, Ann. I note that the count of your posts has just recently passed 2 x 4725 .

Click to view full size image

Jupiter from Pioneer 10 in December, 1973. Photo: NASA.

Thanks! I love your math nerdism.

By the way, I remember something very non-blue, namely the Great Red Spot on Jupiter in 1973, when it was photographed by the probe Pioneer 10. Pioneer 10 was NASA's (and humanity's) first mission to Jupiter.

I remember being rather unimpressed with the aesthetics of the looks of Jupiter in the Pioneer photos. I also remember being fascinated (and slightly turned off) by the huge, incredibly orange Great Red Spot in those pictures, like a huge big smear or even som sort of grotesque "pimple" on the face of the King of Planets. The poor GRS sure has shrunk since its "glory days" in 1973, but the present GRS seems to be as orange as ever.

So while the size of the Great Red Spot has been steadily shrinking, its saturation is clearly variable.

Ann

[sillyworm 2]

How spoiled we are now..this Pioneer 10 photo STILL oozes plenty of exotica.

[geoffrey.landis]

They say that the Great Red Spot is shrinking, but in this picture is looks very large

Yes, that is the "perspective distortion" briefly mentioned in the caption. It's a fisheye lens effect, basically. We're looking at a nearly flat surface from close up. The apparent spherical shape of the planet is mostly the distortion.

Perspective distortion is not the same as fisheye distortion. The shape we're seeing here isn't an apparently spherical object, it's an actual spherical object, and it will always look the same through any lens, from any distance- like a circle

Nope.
The object we are seeing is a spherical object, but spherical objects appear flat if you are close to them.
Flat objects then appear spherical if you view them through a distorting lens.
That's what they mean by "perspective distortion".
Here's an example of the effect: https://apod.nasa.gov/apod/ap121214.html

Click to view full size image

That's a photo of the Earth (which is spherical), taken from the surface of the Earth (so that it looks flat), but distorted (so that it looks spherical).
Exactly the same thing is being done here, except not quite so extreme. The red spot looks too large because of perspective distortion.

[Chris Peterson]

Yes, that is the "perspective distortion" briefly mentioned in the caption. It's a fisheye lens effect, basically. We're looking at a nearly flat surface from close up. The apparent spherical shape of the planet is mostly the distortion.

Perspective distortion is not the same as fisheye distortion. The shape we're seeing here isn't an apparently spherical object, it's an actual spherical object, and it will always look the same through any lens, from any distance- like a circle

Nope.
The object we are seeing is a spherical object, but spherical objects appear flat if you are close to them.

You must live in a very different universe than I do. Every spherical object I've ever seen looks like a circle, and it makes no difference if I'm very far away or if I'm standing on it.

[neufer]

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The object we are seeing is a spherical object, but spherical objects appear flat if you are close to them.

You must live in a very different universe than I do.

Every spherical object I've ever seen looks like a circle, and it makes no difference if I'm very far away or if I'm standing on it.