Io: Moon over Jupiter

This Cassini photo gives an idea on how big Jupiter is: Io is slightly bigger than our Moon: 420 000 km for Io and 384 399 km semi-major axis for the moon.

How big is Jupiter's moon Io? The most volcanic body in the Solar System, Io (usually pronounced "EYE-oh") is 3,600 kilometers in diameter, about the size of planet Earth's single large natural satellite. Gliding past Jupiter at the turn of the millennium, the Cassini spacecraft captured this awe inspiring view of active Io with the largest gas giant as a backdrop, offering a stunning demonstration of the ruling planet's relative size. Although in the above picture Io appears to be located just in front of the swirling Jovian clouds, Io hurtles around its orbit once every 42 hours at a distance of 420,000 kilometers or so from the center of Jupiter. That puts Io nearly 350,000 kilometers above Jupiter's cloud tops, roughly equivalent to the distance between Earth and Moon. The Cassini spacecraft itself was about 10 million kilometers from Jupiter when recording the image data.

Source: APOD

This picture makes me wonder why so many of the "new" space photos appear to be computer graphics.

That photo is kick ass, nice one!

reply to post by Socrato


my exact thought

most the pictures latly are Visually Animated 3D Objects with Applied textures and they're calling them "NEW PICTURES" its like uh????

reply to post by Socrato

This picture makes me wonder why so many of the "new" space photos appear to be computer graphics.

Because they are taken by charge coupled devices through a series of filters. This digital information is then sent to Earth, where it is reassembled into a visual image that approximates something the human eye might see. In the process of turning this digital information into an image, there is often compensation made for movement that occurs between the exposures made through filters of different wavelengths. In effect, they are "computer graphics.

reply to post by DJW001


Your talking about the basic principle of a flatbed scanner CCD(the scanners most of us use). Those satellites don't take scans. And using a singlepass or 3pass that wouldn't alter the real image.

I agree these pictures of lately are more CGI. + the tech filming this stuff is so old that I find it hard to believe it can produce this kind of quality. Not to mention the information that gets lost traveling over that big distance.

But thats just me.

reply to post by Cyanhide

Your talking about the basic principle of a flatbed scanner CCD(the scanners most of us use). Those satellites don't take scans. And using a singlepass or 3pass that wouldn't alter the real image.

Who said anything about scanning? The "cameras"aboard spacecraft these days are digital cameras, CCD's. CCDs do not take true color photographs, they merely record photons. In order to generate a color photo, the light is passed through filters of different colors, then "stacked"or "sandwiched" together. Because different wavelengths of light are useful for detecting things like chemical composition, a wide range of filters is used. These need to be rotated in front of the CCD, during which time the spacecraft will have moved. When the digital data is received on Earth, it is processed to synthesize an image from what is, in effect, a range of data. In effect, it is computer generated, based on real information collected in space.

Interesting. I always thought Io was the smallest of the major Jovian satellites for some reason..

Really nice picture, though!

I always laugh when I see such detailed Hi res pictures of planets and moons in our sloar system.
Because we still can't get Nasa to give us a high resolution close up shot of the lunar surface and the landing site of Apollo. All we get is a pic of a real tiny tiny thing in the distance of what they say is the lunar module.

Thats an awsome photo. Thanks for sharing.

Breathtaking photo of Io

reply to post by elevenaugust


It looks like a marble resting on a wood-grained table. Or resting on an enlarged photograph of another marble. Nice find.

great picture

p.s.: funny how the Moon is always black and white

reply to post by mark1167

I always laugh when I see such detailed Hi res pictures of planets and moons in our sloar system.
Because we still can't get Nasa to give us a high resolution close up shot of the lunar surface and the landing site of Apollo. All we get is a pic of a real tiny tiny thing in the distance of what they say is the lunar module.

Bear in mind that Io is roughly the size of our Moon. Still think that's "Hi-Res?"

Originally posted by elevenaugust
This Cassini photo gives an idea on how big Jupiter is: Io is slightly bigger than our Moon: 420 000 km for Io and 384 399 km semi-major axis for the moon.

Some corrections need to be made here. Firstly, it was Galileo that went to Jupiter. Cassini is at Saturn. Unless this is an image from Cassini when it did a flyby past Jupiter on its way to Saturn.

As for the numbers you gave, they have nothing to do with the size of the Moons. Those are for there orbital characteristics. However you are right in that Io is slightly bigger than our Moon. Io's mean radius: 1,821.3 km. Our Moon's mean radius: 1,737.10 km.

reply to post by jra

Originally posted by jra

Some corrections need to be made here. Firstly, it was Galileo that went to Jupiter. Cassini is at Saturn. Unless this is an image from Cassini when it did a flyby past Jupiter on its way to Saturn.

The article seems to infer just that. These pictures were taken over a decade ago, but just now processed and released.

Gliding past Jupiter at the turn of the millennium, the Cassini spacecraft captured this awe inspiring view of active Io with the largest gas giant as a backdrop, offering a stunning demonstration of the ruling planet's relative size

reply to post by jra



The image was taken by Cassini while it was doing a fly by of Jupiter on it's way to Saturn.

How big is Jupiter's moon Io? The most volcanic body in the Solar System, Io (usually pronounced "EYE-oh") is 3,600 kilometers in diameter, about the size of planet Earth's single large natural satellite. Gliding past Jupiter at the turn of the millennium, the Cassini spacecraft captured this awe inspiring view of active Io with the largest gas giant as a backdrop, offering a stunning demonstration of the ruling planet's relative size. Although in the above picture Io appears to be located just in front of the swirling Jovian clouds, Io hurtles around its orbit once every 42 hours at a distance of 420,000 kilometers or so from the center of Jupiter. That puts Io nearly 350,000 kilometers above Jupiter's cloud tops, roughly equivalent to the distance between Earth and Moon. The Cassini spacecraft itself was about 10 million kilometers from Jupiter when recording the image data.

Source

Here's some info on Cassini's cameras:

Wide Angle Camera [WAC](20 cm f/3.5 refractor; 380-1100 nm; 18 filters; 3.5ox3.5o) Narrow Angle Camera [NAC](2 m f/10.5 reflector; 200-1100 nm; 24 filters; 0.35ox0.35o)

At the heart of each camera is a charged coupled device (CCD) detector consisting of a 1024 square array of pixels, each 12 microns on a side. The data system allows many options for data collection, including choices for on-chip summing and data compression. The narrow-angle camera packs plenty of power too, and could see a quarter -- 2.4 centimeters (0.9 inches) across -- from a distance of nearly 4 kilometers (2.5 miles).

To increase the images' scientific value, each camera on Cassini has two filter wheels designed to take images at specific wavelengths of light. The narrow-angle camera has 12 filters in each wheel for a total of 24 filters; the wide-angle has 9 in each wheel for a total of 18. Some filters only allow light of a certain color to reach the sensor. Combining three such images can produce a color image. The most scientifically interesting images are calibrated in order to turn the electrical signals that emerge from the CCDs into an absolute measure of brightness.

Source

Really great photo. I love coming to ATS and finding this stuff. I wish we had more photos of IO up close. I want to see that sweet volcanic action!

I read a theory in a book a couple weeks ago about Jupitar...

The theory was saying our Solar System could of been one of TWO Stars/Suns .. Jupitar being the second minor Star next to Sol/Sun. The reason Jupitar is now jsut a huge Giant beast roaming our Star/Sun is because it never had enough "power" to totally transverse into a Star and thus it wasnt hot enough either.

Cool theory, imagine if Jupitar would of Transformed!! :O Having two stars on either side of us would be kick assss

Nice photo, CG or not, it still looks like Jupitar and the moon.. Im not complaining lol, thanks for sharing

~ Love is an art

Imagine that behind our moon...
Nice pic. I like blue/green planets more though. This is like big ball of dirt and dust which it actually is
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