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Top Document: [sci.astro] ET Life (Astronomy Frequently Asked Questions) (6/9) Previous Document: F.02.2 Is there life in Jupiter (or Saturn)? Next Document: F.02.4 Is there life on Saturn's moon Titan? See reader questions & answers on this topic! - Help others by sharing your knowledge This article is adapted from NASA Press Releases. In the late 1970's, NASA Voyager spacecraft imaged Europa. Its surface was marked by complicated linear features, appearing like cracks or huge fractures in the surface. No large craters (more than five kilometers in diameter) were easily identifiable. One explanation for this appearance is that the surface is a thin ice crust overlying water or softer ice and that the linear features are fractures in that crust. Galileo images have reinforced the idea that Europa's surface is an ice-crust, showing places on Europa that resemble ice floes in Earth's polar regions, along with suggestions of geyser-like eruptions. Europa's appearance could result from the stresses of the contorting tidal effects of Jupiter's strong gravity (possibly combined with some internal heat from decay of radioactive elements). If the warmth generated by tidal heating is (or has been) enough to liquefy some portion of Europa, then the moon may have environmental niches warm and wet enough to host life. These niches might be similar to those found near ocean-floor vents on the Earth. User Contributions:Comment about this article, ask questions, or add new information about this topic:Top Document: [sci.astro] ET Life (Astronomy Frequently Asked Questions) (6/9) Previous Document: F.02.2 Is there life in Jupiter (or Saturn)? Next Document: F.02.4 Is there life on Saturn's moon Titan? Part0 - Part1 - Part2 - Part3 - Part4 - Part5 - Part6 - Part7 - Part8 - Single Page [ Usenet FAQs | Web FAQs | Documents | RFC Index ] Send corrections/additions to the FAQ Maintainer: jlazio@patriot.net
Last Update March 27 2014 @ 02:11 PM
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[sci.astro] ET Life (Astronomy Frequently Asked Questions) (6/9)
Section - F.02.3 Is there life on Jupiter's moon, Europa?
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[sci.astro] ET Life (Astronomy Frequently Asked Questions) (6/9)
Section - F.02.3 Is there life on Jupiter's moon, Europa?
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with stars, then every direction you looked would eventually end on
the surface of a star, and the whole sky would be as bright as the
surface of the Sun.
Why would anyone assume this? Certainly, we have directions where we look that are dark because something that does not emit light (is not a star) is between us and the light. A close example is in our own solar system. When we look at the Sun (a star) during a solar eclipse the Moon blocks the light. When we look at the inner planets of our solar system (Mercury and Venus) as they pass between us and the Sun, do we not get the same effect, i.e. in the direction of the planet we see no light from the Sun? Those planets simply look like dark spots on the Sun.
Olbers' paradox seems to assume that only stars exist in the universe, but what about the planets? Aren't there more planets than stars, thus more obstructions to light than sources of light?
What may be more interesting is why can we see certain stars seemingly continuously. Are there no planets or other obstructions between them and us? Or is the twinkle in stars just caused by the movement of obstructions across the path of light between the stars and us? I was always told the twinkle defines a star while the steady light reflected by our planets defines a planet. Is that because the planets of our solar system don't have the obstructions between Earth and them to cause a twinkle effect?
9-14-2024 KP