Starship Asterisk*

Jupiter Triple-Moon Conjunction

Explanation: Our solar system's ruling giant planet Jupiter and 3 of its 4 large Galilean moons are captured in this single Hubble snapshot from January 24. Crossing in front of Jupiter's banded cloud tops Europa, Callisto, and Io are framed from lower left to upper right in a rare triple-moon conjunction. Distinguishable by colors alone icy Europa is almost white, Callisto's ancient cratered surface looks dark brown, and volcanic Io appears yellowish. The transiting moons and moon shadows can be identified by sliding your cursor over the image, or following this link. Remarkably, two small, inner Jovian moons, Amalthea and Thebe, along with their shadows, can also be found in the sharp Hubble view. The Galilean moons have diameters of 3,000 to 5,000 kilometers or so, comparable in size to Earth's moon. But odd-shaped Amalthea and Thebe are only about 260 and 100 kilometers across respectively.

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Very nice indeed, and look at the colors of the moons! Callisto is so dark compared with the other moons, Europa is so bright and almost white, and Io is so yellow.

Ann

Depending on the qualifying size of "marbles", this APOD is one to 61 "marbles" short. I noticed that "All The Marbles" is repeated on today's APOD for tomorrow. Perhaps more "marbles" will be shown tomorrow?

bystander wrote: http://asterisk.apod.com/viewtopic.php?p=239367#p239367

Thanks for that link, bystander! There is an image there of Io's shadow and Callisto's shadow right next to one another on the cloudtops of Jupiter. Io's shadow is rather sharp-edged, because Io is the closest one to Jupiter of the Galilean moons, but Callisto's shadow is really fuzzy, because Callisto is so far away.

Nice pictures!

Ann

Mark your calendars young ones. On 22 November 2065 – Venus transits Jupiter. Maybe it will look like this simulation. Maybe it will be quite better?
What useful science could they derive from it? For instance could a satellite in Venus's L2 point study the suns corona. Or like in this link; a L1 point mirror which may alter the sun's harsh effects to allow for possible habitation? No telling what we may be capable of in 2065.

http://en.wikipedia.org/wiki/Terraforming_of_Venus

I'll be trying to block the light of 111 candles should I be habitating.

who, or what can predict these events ?

ta152h0 wrote:who, or what can predict these events ?

It's just orbital dynamics. We know the orbital elements of all the planets and moons, and over short periods (decades to millennia, depending on the body) we can calculate with very high accuracy where bodies will be.

Any planetarium program will let you look for events like this, and there are automated programs that will run the same math and identify them without the need to manually scan through the years. There are lots of websites offering such information, along with all manner of astronomical events. Magazines like Sky & Telescope will warn you about them several months in advance, as well.

I guess Amalthea and Thebe, along with their shadows, can be found on the the left of Callisto's shadow. Am I right?

Astronymus wrote:I guess Amalthea and Thebe, along with their shadows, can be found on the the left of Callisto's shadow. Am I right?

Left and below. The link in the caption leads to an annotated image.

Awesome.

Hubble never fails to impress...to see darker features on these moons is great. The colors are outstanding.

:---[===] *

Ron-Astro Pharmacist wrote:Mark your calendars young ones. On 22 November 2065 – Venus transits Jupiter. Maybe it will look like this simulation. Maybe it will be quite better?
.

Ah, but I bet most of you missed the big one, because you were celebrating New Year's Eve! http://henry.pha.jhu.edu/Transit.of.Earth.pdf

The confusing part of the image is the location of the shadows, had to watch this animation a few times to figure it out http://heritage.stsci.edu/2015/05/

Apparently you don't see the upper right moon Io's shadow, and Callisto's is the upper right shadow.

Can anyone tell me what might be the cause of the small, blood-red, oval spot on Jupiter at about 11:30 between the center and edge of the Jovian disc? It appears to be an intense, small (small by Jovian standards) storm, but the color is what I find puzzling.

I hate to show my ignorance but how many miles from the sun is Jupiter?

DRBUCK917@ wrote:I hate to show my ignorance but how many miles from the sun is Jupiter?

484 million.

Google (and other search engines) have a useful ability to pop out many useful numbers such as this. You can search for terms such as "distance of jupiter from sun in miles" and get a number back quickly. Also try things such as "diameter of jupiter" and "length of jupiter day"

DRBUCK917@ wrote:I hate to show my ignorance but how many miles from the sun is Jupiter?

A fun website to visit, and so is the actual model at Cornell.
http://en.wikipedia.org/wiki/Sagan_Planet_Walk

quigley wrote:Can anyone tell me what might be the cause of the small, blood-red, oval spot on Jupiter at about 11:30 between the center and edge of the Jovian disc? It appears to be an intense, small (small by Jovian standards) storm, but the color is what I find puzzling.

A wayward drop of red dye no. 12, perhaps?

No, seriously, I happened to have read just today a little news story in a recent Sky and Telescope reporting on a finding that the red colors on Jupiter were from cloud tops were UV light from the Sun causes ammonia and another chemical to react, forming a red compound. That radish redish spot you spotted might be a particularly tall cloud formation, reaching up to where the thinner atmosphere allows more UV to penetrate.

Bruce

One would think the shadow of Callisto should be long and elliptical, given its distance and angle... Europa's shadow being circular is more expected given the proximity. ...what's up with that?

pbr wrote:One would think the shadow of Callisto should be long and elliptical, given its distance and angle... Europa's shadow being circular is more expected given the proximity. ...what's up with that?

The telescopic view is disorienting. Everything looks flat from the face of Jupiter to the moons. Even a shadow being cast on the edge of Jupiter will appear nearly circular from our position. It might help to view the animation: http://heritage.stsci.edu/2015/05/image ... 150202.gif

Mactavish wrote:

DRBUCK917@ wrote:I hate to show my ignorance but how many miles from the sun is Jupiter?

A fun website to visit, and so is the actual model at Cornell.
http://en.wikipedia.org/wiki/Sagan_Planet_Walk

Another one is
http://nineplanets.org/
Many fun facts and images

geckzilla wrote:

pbr wrote:One would think the shadow of Callisto should be long and elliptical, given its distance and angle... Europa's shadow being circular is more expected given the proximity. ...what's up with that?

The telescopic view is disorienting. Everything looks flat from the face of Jupiter to the moons. Even a shadow being cast on the edge of Jupiter will appear nearly circular from our position. It might help to view the animation: http://heritage.stsci.edu/2015/05/image ... 150202.gif

That animated view in the link you provided I think shows another very tiny moon not yet discussed. Look for two tiny specs that follow each-other along the equator.