Sunday, October 23, 2016

Water Worlds in the Solar System

There is new evidence for the existence of liquid water in the cold outer regions of our solar system. Astronomers using the Hubble Telescope see a plume of water erupting from the surface of Jupiter’s moon Europa, and measurements of Saturn’s little moon Dione indicate that it must have a substantial layer of liquid water deep underground.
In recent years, more and more evidence has accumulated that liquid water exists among the moons of the giant planets. We have known for a while that there is likely to be an underground ocean of water beneath the icy crust of Jupiter’s moon Europa, and perhaps also under the surface of its moon Ganymede (the largest moon in the solar system.)

Then the Cassini mission found great geysers of salt water emerging from the icy cracks on Saturn’s moon Enceladus, a world much smaller than the Jupiter moons we just discussed. The big deal here is not that there is water, since water ice makes up a large part of many of the solid worlds in the outer solar system. The big discovery is that, even in those icy realms, enough heat can be generated inside these moons to have oceans of liquid water.
The Hubble work is the second report of plumes coming out of cracks in the ice of Europa. Earlier work, also done with the Hubble, also hinted at such plumes, but now astronomers have observed them in ultraviolet light as Europa was crossing the face of Jupiter. Our top image shows you what was observed, with a visible-light picture of Europa photoshopped in to show you what the moon looks like. A short NASA movie explaining the discovery can be seen at:
The work on Dione was more indirect. This moon of Saturn’s is about 700 mi across, more than twice as big as Enceladus. The presence of water was suggested by measurement of the gravity of Dione, as the Cassini spacecraft flew by it. The gravity measurements fit with the presence of a water layer deep inside the moon, perhaps 60 mi beneath the surface.
(The bottom image shows a very detailed image of Dione's surface from the Cassini spacecraft.  You see many icy cracks and fractures, whose sides show as white cliffs.)
Something must heat the buried “oceans” in these moons to keep them liquid. In some cases, it is a tug of war between the gravity of the mother planet on one side, and a large moon on the other. Or it may be some kind of rocking back and forth, which scientists call “libration”. Whatever allows liquid water layers to exist out there, the fact that they do makes them an interesting place to look for the beginnings of life.

1 comment:

  1. Urgent Real Love Spell That Work Fast On How To Get Your Ex, Husband, Wife Back My life became devastated when my husband sent me packing, after 8 years that we have been together. I was lost and helpless after trying so many ways to make my husband take me back. One day at work, i was absent minded not knowing that my boss was calling me, so he sat and asked me what its was all about i told him and he smiled and said that it was not a problem. I never understand what he meant by it wasn't a problem getting my husband back, he said he used a spell to get his wife back when she left him for another man and now they are together till date and at first i was shocked hearing such thing from my boss. He gave me an email address of the great spell caster who helped him get his wife back, i never believed this would work but i had no choice that to get in contact with the spell caster which i did, and he requested for my information and that of my husband to enable him cast the spell and i sent him the details, but after two days, my mom called me that my husband came pleading that he wants me back, i never believed it because it was just like a dream and i had to rush down to my mothers place and to my greatest surprise, my husband was kneeling before me pleading for forgiveness that he wants me and the kid back home, then i gave Happy a call regarding sudden change of my husband and he made it clear to me that my husband will love me till the end of the world, that he will never leave my sight. Now me and my husband is back together again and has started doing pleasant things he hasn't done before, he makes me happy and do what he is suppose to do as a man without nagging. Please if you need help of any kind, kindly contact Happy for help and you can reach him via email: you can also call him or add him on whats-app +2348133873774