Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2002 June 2 
Posted on 06/01/2002 9:32:57 PM PDT by petuniasevan
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2002 June 2
Explanation: Which way to the interstate? What appears to be a caricature of a complex highway system on Earth is actually a system of ridges and cracks on the icy surface of Jupiter's moon Europa. The distance between parallel ridges in the above photograph is typically about 1 kilometer. The complexity of the cracks and ridges tell a story of Europa's past that is mostly undecipherable -- planetary geologists try to understand just the general origin of the overall features. One noteworthy feature is the overall white sheen, possibly indicating the presence of frost. Another is the dark centers between parallel ridges, which might indicate that dirty water from an underground ocean recently welled up in the cracks and froze. Recent research indicates that enough carbon exists to support an underwater biosphere, but that Europa's ice crust may be over three kilometers thick in some places.
But don't be looking for any manned missions for the foreseeable future. Reason?
Europa lies deep within the magnetosphere of Jupiter, which is the volume of space above Jupiter's atmosphere that is affected by Jupiter's magnetic field.
This magnetosphere extends up to 10 million km from Jupiter (i.e., it encompasses a volume 1,000 times that of the Sun) and is filled with ionizing, magnetically trapped particle radiation.
The mechanism of magnetic trapping of radiation at Jupiter is the same as that which operates in Earth's van Allen belts.
Jupiter's magnetosphere is, aside from the Sun, the dominant source of energetic charged particles and radio emissions in the solar system.
Translation? The radiation would fry you in a short time. It's that bad.
A manned mission would have to proceed under heavy shielding, then burrow under the ice on arrival, within 10 minutes,
to avoid heavy irradiation.
I expect the usual 2001: A Space Odyssey jokes. I'm sure you APOD posters won't disappoint!
Get on the APOD PING list! 
I know who I'd like to comment on this message... I'm going to just go ahead and yank him onto the thread, selfishly...RA!!! I'm not going to drag you into semantic content or the physics of turning jupiter into a sun...I'm just wondering how you decorate your office at Seti? Any posters or cartoons that have been stuck on a bulletin board so long they've turned yellow but noone has the heart to throw them out...The longest posted joke at my last company was a choice little defense for a manufacturer of instrumentation which it was...
"Your criticism of this product is evidence of an unsound technical background."
BR SS
Sorry I haven't visited in a few days, but this is why : Prayers needed for a dying newborn girl.
open the apod door, hal.
It's Calvin looking up at the stars and screams I'm significant! In the next frame you see him walking away quietly with the caption "Said the dust speck"
Does Broad Spectrum EM Radiation Minister sound okay as a working title for you?
A word of advice on time management...Number one rule of Parliamentary procedure...
A Motion to ADJOURN is ALWAYS in order. Full stop...
Don't let my rantings make you feel responsible to enlighten me...I'm ruined by all the science fiction I've read...Just smile if you see something you like and if I bug you...let me know how...You are my eyes and ears on the universe guys...Lets ROLL applies to you too in my book of priorities...FREEP MARS!!!!
Amazingly, Women are signing up to emigrate too...See Libertina about a visa...those with needed skills can be extra unkempt and get bigger quarters and a better view of the Artillery Impact Area and Recreational Impossiblities Church arena...Check with Tonkin if you have ideas! BTW I 2010'd you in the first post of mine on this thread and you missed it, boyo...
There we could hold the Inter-Planetary Stanley Cup finals. ;^)
Hey man...Keep your stick on the Ice, be it Carbon Dioxide, Methane or good old DiHydrogen Oxide!!!
We could start with a golf course. ;^)
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