APOD: Gibbous Europa (2011 Jan 30)

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APOD: Gibbous Europa (2011 Jan 30)

Post by APOD Robot » Sun Jan 30, 2011 5:06 am

Image Gibbous Europa

Explanation: Although the phase of this moon might appear familiar, the moon itself might not. In fact, this gibbous phase shows part of Jupiter's moon Europa. The robot spacecraft Galileo captured this image mosaic during its mission orbiting Jupiter from 1995 - 2003. Visible are plains of bright ice, cracks that run to the horizon, and dark patches that likely contain both ice and dirt. Raised terrain is particularly apparent near the terminator, where it casts shadows. Europa is nearly the same size as Earth's Moon, but much smoother, showing few highlands or large impact craters. Evidence and images from the Galileo spacecraft, indicated that liquid oceans might exist below the icy surface. To test speculation that these seas hold life, NASA and ESA have started preliminary development of the Europa Jupiter System Mission, a spacecraft proposed for launch around 2020 that would further explore Jupiter and in particular Europa. If the surface ice is thin enough, a future mission might drop hydrobots to burrow into the oceans and search for life.

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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by Boomer12k » Sun Jan 30, 2011 12:18 pm

Must have lots of MOTOCROSS on Europa!!!!

Or more likely, SNOWMOBILING!!!!!

HEY, SNOWMOBILE MOTOCROSS!!!!!!

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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by Céline Richard » Sun Jan 30, 2011 12:36 pm

Hello :)

This is such a great, wonderful picture!
In the other image http://www.nasaimages.org/luna/servlet/ ... t-hydrobot it seems there is water below ice on Europa. I hope hydrorobots will find out very interesting life forms over there.
The spacecraft Galileo was launched on October 18, 1989. It arrived at Jupiter on December 7, 1995. So it took a very long time, more than six years, to reach Europa. Before this spacecraft provides answers to their curiosity, astrophysicians need patience :)

Have a very nice day!

Céline
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pacfandave1

Re: APOD: Gibbous Europa (2011 Jan 30)

Post by pacfandave1 » Sun Jan 30, 2011 12:38 pm

Here's my problem with our current space program. We've already demonstrated that we can send a spacecraft to anywhere in the Solar System. We're talking about yet another trip to Europa and Jupiter, to a near-Earth astroid, building a moon base, and a manned flight to Mars. To what purpose? Suppose there is life on Europa? So what? I believe we should shift all space funding to developing spacecraft propulsion systems that will dramatically reduce travel time over light-year distances. We need to start probing earth-like planets orbiting relatively nearby stars. Our future is not going to be in terraforming Mars; when the sun goes nova Mars will be just as gone as we.

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"ALL THESE WORLDS ARE YOURS - EXCEPT EUROPA"

Post by neufer » Sun Jan 30, 2011 2:54 pm

http://en.wikipedia.org/wiki/2010:_Odyssey_Two wrote:
<<2010: Odyssey Two is a best-selling science fiction novel by Arthur C. Clarke, which was published in January 1982. Clarke peppered the novel with names of various Soviet dissidents, including physicists Andrei Sakharov and Yuri Orlov, human-rights activists Mykola Rudenko and Anatoly Marchenko, Russian Orthodox activist Gleb Yakunin, among others.

The story is set nine years after the failure of the Discovery One mission to Jupiter.

A joint Soviet-American crew, including Heywood Floyd from 2001, on the Soviet spaceship Alexei Leonov (named after the famous cosmonaut) arrives to discover what went wrong with the earlier mission, to investigate the monolith in orbit around the planet, and to resolve the disappearance of David Bowman. They hypothesize that much of this information is locked away on the now-abandoned Discovery One. The Soviets have an advanced new "Sakharov" drive which will propel them to Jupiter ahead of the American Discovery Two, so Floyd is assigned to the Leonov crew.

However, a Chinese space station rockets out of Earth orbit, revealing itself to be the interplanetary spacecraft Tsien, also aimed at Jupiter. The Leonov crewmembers think the Chinese are on a one-way trip due to its speed, but Floyd surmises that due to the large water content of Europa they intend to land there and use the water content to refuel. The Tsien's daring mission ends in failure, when it is destroyed by an indigenous life-form on Europa. The only survivor radios the story to the Leonov; it is presumed that he dies when his spacesuit air supply runs out.

The Leonov survives a dangerous aerobraking around Jupiter and arrives at Discovery. Mission crewmember and HAL 9000's creator, Dr. Chandra, reactivates the computer to ascertain the cause of his earlier aberrant behavior.

A sequence of scenes follows the explorations of David Bowman, who has been transformed into a non-corporeal, energy-based life-form, much like the aliens controlling the monoliths. During his journey, the avatar of Bowman travels to Earth, making contact with significant individuals from his human past: He visits his mother and brushes her hair (shortly before she dies), and he appears to his ex-girlfriend on her television screen. In the novel, the aliens are using Bowman as a probe to learn about humankind. He then returns to the Jupiter system to explore beneath the ice of Europa, where he finds aquatic life-forms, and under the clouds of Jupiter, where he discovers gaseous life-forms. Both are primitive, but the aliens deem the Europan creatures to have evolutionary potential.

An apparition of Bowman appears before Floyd, warning him that they must leave Jupiter within 15 days. Floyd has difficulty convincing the rest of the crew at first, but then the monolith vanishes from orbit and a mysterious dark spot on Jupiter begins to form and starts growing. HAL's telescope observations reveal that the "Great Black Spot" is, in fact, a vast population of monoliths, increasing at an exponential rate, which appear to be eating the planet.

The Leonov crew devises a plan to use the Discovery as a "booster rocket", enabling them to return to Earth ahead of schedule. Unfortunately, HAL and the Discovery will be trapped in Jupiter's orbit, with insufficient fuel to escape. The crew are worried that HAL will have the same neuroses on discovering that he will be abandoned yet again, and Chandra must convince HAL that the human crew is in danger.

The Leonov crew flees Jupiter as the swarm of monoliths spread to engulf the planet. Through a mechanism the novel only partially explains, these monoliths increase Jupiter's density until the planet achieves nuclear fusion, becoming a small star. In the novel, this obliterates the primitive life forms inhabiting the Jovian atmosphere, which the Monoliths' controllers had deemed less worthy than the aquatic life of Europa.
[img3=""The Europans who explore the Farside have begun to develop
a mythology based on their observations."
"]https://www.ibm.com/developerworks/myde ... e-duck.jpg[/img3]
As Jupiter is about to transform, Bowman returns to Discovery to give HAL a last order to carry out. HAL begins repeatedly broadcasting the message "ALL THESE WORLDS ARE YOURS EXCEPT EUROPA. ATTEMPT NO LANDINGS THERE." The creation of the new star, which Earth eventually names Lucifer, destroys Discovery. However, HAL's artificial intelligence is removed from Discovery's computer core and transformed into the same kind of life form as David Bowman, and becomes his companion.

The book ends with a brief epilogue, which takes place in AD 20,001. By this time, the Europans have evolved into a species that has developed a primitive civilization, most likely with assistance from a monolith. They are not described in detail, though they are said to have "tendril"-like limbs. They regard the star Lucifer (formerly the planet Jupiter) as their primary Sun, referring to Sol as "The Cold Sun". Though their settlements are concentrated primarily in the hemisphere of Europa which is constantly bathed in Lucifer's rays, some Europans have begun in recent generations to explore the Farside, the hemisphere facing away from Lucifer, which is still covered in ice. There they may witness the spectacle of night, unknown on the other side of Europa, when the Cold Sun sets.

The Europans who explore the Farside have been carefully observing the night sky and have begun to develop a mythology based on their observations. They correctly believe that Lucifer was not always there. They believe that the Cold Sun was its brother and was condemned to march around the sky for a crime. The Europans also see three other major bodies in the sky. One seems to be constantly engulfed in fire, and the other two have lights on them which are gradually spreading. These three bodies are the moons Io, Callisto, and Ganymede, the latter two of which are presently being colonized by humans.

Humans have been attempting to explore Europa ever since Lucifer was created in 2010. However, none of these attempts has been successful. Every probe that has attempted to land on Europa has been destroyed in the atmosphere; as it is later shown in 2061 and 3001 manned spacecraft that attempt to land have been instead diverted by an external force. The debris from every probe falls to the surface of the planet, and the debris from some of the first ships to be destroyed is venerated by the Europans.

Finally, there is a Monolith on the planet, which is worshipped by the Europans more than anything else. The Europans assume, correctly, that the Monolith is what keeps humans at bay. Dave Bowman and HAL lie dormant in this Monolith. The Monolith is the guardian of Europa, and will continue to prevent contact between humans and Europans for as long as it sees fit.>>
Art Neuendorffer

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Dirt on Europa

Post by napewastewin » Sun Jan 30, 2011 4:12 pm

. . . or any other planet or planet's moon, for that matter: What, exactly comprises the "dirt" on these. That word is used in the explanation of today's picture. What is said "dirt" made of? What are the components of "dirt" on Mars? How does it differ from that on Earth?

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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by Chris Peterson » Sun Jan 30, 2011 5:04 pm

pacfandave1 wrote:Here's my problem with our current space program. We've already demonstrated that we can send a spacecraft to anywhere in the Solar System. We're talking about yet another trip to Europa and Jupiter, to a near-Earth astroid, building a moon base, and a manned flight to Mars. To what purpose? Suppose there is life on Europa? So what?
Each new mission carries different instrumentation, intended to conduct new experiments suggested by the results of previous missions. That is precisely how science is supposed to work. We're out there to gain an understanding about the Solar System, how it was formed, how it evolved, and by extension, how other stellar systems form and evolve.
I believe we should shift all space funding to developing spacecraft propulsion systems that will dramatically reduce travel time over light-year distances. We need to start probing earth-like planets orbiting relatively nearby stars. Our future is not going to be in terraforming Mars; when the sun goes nova Mars will be just as gone as we.
That would be a waste of time and resources at this point. Maybe you don't realize just how incredibly difficult getting to another star really is. We have nowhere near enough technology developed to achieve this. And more to the point, we lack the social stability to plan and operate a program that could not hope to produce results for many decades, if not centuries. We are simply too immature as a technological and social species. Perhaps in a few centuries (if we survive, which seems doubtful to me). In the meantime, there is more than enough to keep us busy right here around our own sun.

(Even if we could readily develop the technology to get to another planetary system, what would we send there? We still haven't figured out how to really analyze other planets remotely- even our own. That's a big part of what we are learning to do with our current in-system planetary exploration.)
Chris

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Re: Dirt on Europa

Post by neufer » Sun Jan 30, 2011 5:27 pm

APOD Robot wrote:Image Gibbous Europa

Visible are plains of bright ice, cracks that run to the horizon, and dark patches that likely contain both ice and dirt.
napewastewin wrote:
What, exactly comprises the "dirt" on these. That word is used in the explanation of today's picture.
Gibbous something sulfurous such as on Io: http://apod.nasa.gov/apod/ap101003.html
http://en.wikipedia.org/wiki/Europa_%28moon%29 wrote:
<<Spectrographic evidence suggests that the dark, reddish streaks and features on Europa's surface may be rich in salts such as magnesium sulfate, deposited by evaporating water that emerged from within. Sulfuric acid hydrate is another possible explanation for the contaminant observed spectroscopically. In either case, since these materials are colorless or white when pure, some other material must also be present to account for the reddish color, and sulfur compounds are suspected.>>
Art Neuendorffer

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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by orin stepanek » Sun Jan 30, 2011 6:28 pm

Can there be life?
Click to play embedded YouTube video.
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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by Beyond » Sun Jan 30, 2011 7:01 pm

Unscientifically speaking, i think Europa is in need of a very good face cream. Of course i may be on very thin ice for saying that. :D
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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by nstahl » Sun Jan 30, 2011 11:57 pm

Those interested in traveling to a different star system might want to look through the many posts at Project Icarus for a presumably realistic view of what would be involved with our technology and prospective technology.

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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by Boomer12k » Mon Jan 31, 2011 12:09 am

pacfandave1 wrote:Here's my problem with our current space program. We've already demonstrated that we can send a spacecraft to anywhere in the Solar System. We're talking about yet another trip to Europa and Jupiter, to a near-Earth astroid, building a moon base, and a manned flight to Mars. To what purpose? Suppose there is life on Europa? So what? I believe we should shift all space funding to developing spacecraft propulsion systems that will dramatically reduce travel time over light-year distances. We need to start probing earth-like planets orbiting relatively nearby stars. Our future is not going to be in terraforming Mars; when the sun goes nova Mars will be just as gone as we.

The Sun does not go supernova. It goes red giant. That is in about another 5 billion years. Plenty of time to develop space travel. If we don't kill ourselves before then.

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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by biddie67 » Mon Jan 31, 2011 2:23 am

Will the Europa Jupiter System Mission have some kind of land-penetrating radar incorporated into its instrumentation to penetrate the land-mass of Europa (analogous to what the oil industry uses to locate possible sub-surface structures that might hold oil) that can map the sub-surfaces? Seems like this might be a method to locate the best places to drop in the "hydrobots".

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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by bystander » Mon Jan 31, 2011 3:16 am

Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by biddie67 » Mon Jan 31, 2011 3:55 am

Thanks bystander !!

Gimmeslack12

Re: APOD: Gibbous Europa (2011 Jan 30)

Post by Gimmeslack12 » Mon Jan 31, 2011 4:58 am

pacfandave1 wrote:Here's my problem with our current space program. We've already demonstrated that we can send a spacecraft to anywhere in the Solar System. We're talking about yet another trip to Europa and Jupiter, to a near-Earth astroid, building a moon base, and a manned flight to Mars. To what purpose? Suppose there is life on Europa? So what? I believe we should shift all space funding to developing spacecraft propulsion systems that will dramatically reduce travel time over light-year distances. We need to start probing earth-like planets orbiting relatively nearby stars. Our future is not going to be in terraforming Mars; when the sun goes nova Mars will be just as gone as we.
Dramatically reduce travel time over light-year distances? Umm, not to say this isn't a good idea but you have to consider the units of "Light Year Distances" is mind boggling. 1 light-year = 5,870,000,000,000 miles (5 Trillion)!!!!!!!!!

To put it in context, Pluto is roughly 0.001 light-years away (13 light hours) and that will take the New Horizons probe about 10 years. If it takes us 10 years to go 0.1% of a light year then we aren't anywhere near beginning to tackle a full on light-year. Not to mention to even get to the nearest star we'll need to get over 4 light years out!

I think Europa is a much more realistic target than light-year travel.

Garry

Re: APOD: Gibbous Europa (2011 Jan 30)

Post by Garry » Mon Jan 31, 2011 5:51 am

In the close up pictures of Europa, the cracks look more like furrows with ridges either side. As though the surface has been ploughed in different directions. Also there are "furrows" that are comprised of shallow loops. Another explanation as to the cause?

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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by Céline Richard » Tue Feb 01, 2011 9:53 am

Hello :)
orin stepanek wrote:Can there be life?
Click to play embedded YouTube video.
Thank you!!! Very interesting :)
It is great to be able to get the dimensions of Europa, with enough accuracy, in order to determine how tides, below the icy surface of this satellite, can change the form of Europa! It might be so difficult to go through this icy surface, to reach the oceanic liquid water below.
There is a picture showing the spacecraft near a sort of blue fountain on Io (2mins 33s), to get material from it. It doesn't look like to a volcano, but if it is a volcano, does anyone know why it is blue?
I wonder too why Europa is more interesting to analyze compared with the other Jupiter's moons, if Ganymede and Callisto also may have internal oceans.
Have a very nice day!

Céline
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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by neufer » Tue Feb 01, 2011 12:59 pm

Céline Richard wrote:
There is a picture showing the spacecraft near a sort of blue fountain on Io (2mins 33s), to get material from it. It doesn't look like to a volcano, but if it is a volcano, does anyone know why it is blue?
Particles (including molecules) much smaller than 0.5 microns will be Rayleigh scatterers that are much more effective in scattering blue light than red light. (It is the same reason that the sky is blue.)
Céline Richard wrote:
I wonder too why Europa is more interesting to analyze compared with the other Jupiter's moons, if Ganymede and Callisto also may have internal oceans.
Have a very nice day!
The cracks on Europa indicate that the overlying ice sheet may be thin enough to penetrate with robotic spacecraft.
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Ocean on Europa

Post by Skyman55 » Fri Feb 04, 2011 1:54 pm

Hi to all - just joined this forum today.

My question
In a recent documentary, it was stated that the Ocean beneath the ice on Europa is salty. I was of the opinion that the reason for the salty oceans on Earth was the erosion of minerals from the land mass as rain runs off into the sea.

What process makes the ocean salty on Europa ?

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Re: Ocean on Europa

Post by Skyman55 » Fri Feb 04, 2011 2:07 pm

Hi

Just realised that my question is in the wrong section of the forum - I will place future posts in the correct place

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Re: APOD: Gibbous Europa (2011 Jan 30)

Post by Céline Richard » Fri Feb 04, 2011 3:01 pm

neufer wrote:Particles (including molecules) much smaller than 0.5 microns will be Rayleigh scatterers that are much more effective in scattering blue light than red light. (It is the same reason that the sky is blue.)
(...) The cracks on Europa indicate that the overlying ice sheet may be thin enough to penetrate with robotic spacecraft.
Thank you a lot Art :) I understand better now.

Céline
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