APOD: Two Views of Earth (2013 Jul 23)

[Billsey]

What's the comet-looking thing in the far right of the Messenger shot?

[neufer]

Click to play embedded YouTube video.

would someone identify the blue band of light across the picture in the Saturn photo thankyou

My guess is that this might possibly be the E ring, made of ice particles ejected by active moon Enceladus. These tiny ice particles create a broad, diffuse ring aroung Saturn. The E ring is also blue in color, which seems to fit what we are seeing here.

No guessing needed. It's most definitely the E ring. One reason for taking the photo of Saturn with the Sun completely occluded is to make the E ring stand out.

[b][color=#0000FF]The backlit E ring, with Enceladus silhouetted against it. The moon's south polar jets erupt brightly below it.[/color][/b]

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<<The E Ring is the second outermost ring, and is extremely wide, beginning at the orbit of Mimas and ending somewhere around the orbit of Rhea. It is a diffuse disk consisting mostly of ice, with silicates, carbon dioxide and ammonia. Unlike the other rings, it is composed of microscopic particles rather than macroscopic ice chunks. In 2005, the source of the E Ring's material was determined to be cryovolcanic plumesemanating from the "tiger stripes" of the south polar region of the moon Enceladus. Unlike the main rings, the E Ring is more than 2000 kilometers thick and increases with its distance from Enceladus.

Particles of the E-ring tend to accumulate on moons that orbit within it. The equator of the leading hemisphere of Tethys is tinted slightly blue due to infalling material. The trojan moons Telesto, Calypso, Helene and Polydeuces are particularly affected as their orbits move up and down the ring plane. This results in their surfaces being coated with bright material that smooths out features.>>

[Indigo_Sunrise]

Very cool image/s!


Billsey, my guess is it's most likely an imperfection that wasn't removed from the image. Maybe someone will come along and let us both know for sure.

[Beyond]

Click to play embedded YouTube video.

Ahhh, the Original Blue Band And looka the fancy footwork from those way-out Stars Their orbits decayed too soon.

[Bob in MD]

That's me over at the left side of the pixel, waving between two clouds.

[neufer]

Ahhh, the Original Blue Band And looka the fancy footwork from those way-out Stars Their orbits decayed too soon.

You can still talk with one of them (with or without a spirit medium).

<<Daniel Edward "Dan" Aykroyd, CM (born July 1, 1952) was an original cast member of Saturday Night Live, an originator of The Blues Brothers (with John Belushi) and Ghostbusters, and has had a long career as a film actor and screenwriter. Aykroyd also helped start the Blue Line Foundation [who] are redeveloping flood damaged lots in New Orleans and helping first responders buy them at reduced prices.

Aykroyd considers himself a Spiritualist. His great-grandfather, a dentist, was a mystic who corresponded with author Sir Arthur Conan Doyle on the subject of Spiritualism, and who was a member of the Lily Dale Society. On September 29, 2009, Peter Aykroyd, father of Dan Aykroyd, published a book entitled, A History of Ghosts. This book chronicled the family's historical involvement in the Spiritualist Movement, to which Aykroyd readily refers. Aykroyd is also interested in various other aspects of the paranormal, particularly UFOlogy. He is a lifetime member of and official Hollywood consultant for the Mutual UFO Network. In 2005, Aykroyd produced a DVD titled, Dan Aykroyd: Unplugged on UFOs. In it, he is interviewed for 80 minutes by UFOlogist David Sereda where he discusses in depth every aspect of the UFO phenomenon, and reveals specifically that they are blue, not green, but appear that way because of a filter. The Committee for the Scientific Investigation of Claims of the Paranormal awarded Aykroyd the Snuffed Candle award, for "contributing to the public's lack of understanding of the methods of scientific inquiry.">>

[Beyond]

Snuffed Candle award Foist tyme eye ever herd a dat.

[quigley]

So in the Cassini image, is the moon positioned behind the Earth in its orbit, or is it just too faint to appear in this spectacular image, which I believe DOES definitely have a purpose--to AMAZE US!

[dstn]

If you blink between the annotated and un-annotated versions,
http://broiler.astrometry.net/~dstn/temp/17171.jpg
http://broiler.astrometry.net/~dstn/temp/17171-ann.jpg

you can see that at the point the image was taken, the moon was about 10 days away from being in-line with Earth as seen from Saturn, so at maybe half the max separation, just a few pixels in that image. My guess is that the moon is just fainter and blends into the Earth blob.

(PS, the sizes of the dots on the annotation are not to scale, but the positions of Earth and the moon are correct)

cheers,
dustin

[dstn]

Actually, is it just me, (or just a JPEG artifact), but I think I *can* see one brighter-gray pixel to the right and down one pixel from the Earth center. That's about the right distance and orientation for the Moon.

[geckzilla]

Actually, is it just me, (or just a JPEG artifact), but I think I *can* see one brighter-gray pixel to the right and down one pixel from the Earth center. That's about the right distance and orientation for the Moon.

The Moon can be clearly seen in both the annotated jpg image on this page as well as the uncompressed tiff. The jpg compression in the image at the link under the tiff link destroys the Moon.
http://photojournal.jpl.nasa.gov/catalog/PIA17171

[neufer]

[size=115][b][color=#0000FF]Astrobob: In preparation for a future flyby of Earth on its way to insertion into orbit around Mercury the MESSENGER spacecraft's [u]narrow-angle camera[/u] took this photo of the Earth-moon system from a distance of 18.4 million miles on May 11, 2005.[/color] Credit: NASA[/b][/size]

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I appreciate the Earth and Moon trails. Now I can better imagine that I'm there watching home fly distantly by!

I like that you can see the orbit of the Moon over the two-month period; it also gives you an idea of how far apart Earth and the Moon *could* have looked.

<<MESSENGER's Mercury Dual Imaging System (MDIS) has wide- and narrow-angle cameras. The wide-angle camera [WAC: used in today's APOD for a Mercury moon search] has a 10.5° by 10.5° field of view and can observe Mercury through 11 different filters & monochrome across the wavelength range 395 to 1,040 nanometers. Multi-spectral imaging will help scientists investigate the diversity of rock types that form Mercury’s surface. The narrow-angle camera [NAC] can take black-and-white images at high resolution through its 1.5° by 1.5° field of view.>>

[Guest]

Have been looking at APOD everyday for years, and this picture is my new favourite Thank-you APOD

[JimW]

Considering the view of Earth from Saturn, one thing has me puzzled. If the Sun is behind Saturn, and Earth is between Saturn and the Sun, shouldn't Earth appear as a crescent shape rather than a full circle (similar to views of Venus from Earth)? I cannot see any hint of Earth's night side in this photo. If the Sun is between Saturn and Earth in this view, I can understand the circular shape of Earth, but based on the distances stated, that configuration does not appear to be the case. Please help me understand what I think I am seeing in this spectacular photo. Thank you.

[neufer]

[b][color=#0000FF][size=150]How Earth should have appeared on July 19 to the Cassini spacecraft at Saturn. Credit: NASA[/size][/color][/b]

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Considering the view of Earth from Saturn, one thing has me puzzled. If the Sun is behind Saturn, and Earth is between Saturn and the Sun, shouldn't Earth appear as a crescent shape rather than a full circle (similar to views of Venus from Earth)? I cannot see any hint of Earth's night side in this photo. If the Sun is between Saturn and Earth in this view, I can understand the circular shape of Earth, but based on the distances stated, that configuration does not appear to be the case. Please help me understand what I think I am seeing in this spectacular photo. Thank you.

It's simply a resolution problem.