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Cassini Focuses In On Two Moons

Cassini Focuses In On Two Moons

by Ray Sanders on August 8, 2011

Image of Tethys and Titan taken in green visible light on July 14th 2011 at a distance of about 3.2 million kilometers from Titan. Image Credit: NASA/JPL/Space Science Institute

In this new image from the Cassini Imaging Team Saturn’s moon Titan looks a little out of focus compared to the sharp, cratered surface of Tethys, seen in the foreground. But that’s only because Titan’s hazy atmosphere makes the moon look blurry. Titan’s current atmosphere is thought to resemble Earth’s early atmosphere, so we could be looking at an analog of early Earth.

And so, the Cassini mission is sharpening our understanding of Saturn and all its moons, but it might help us understand our own planet, as well.
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The way Hollywood envisions moving at light speed doesn't really work - since it still implies that you move a certain distance over a certain time period. As far as a photon is concerned, it does neither. Source: zidbits.

From a photon’s point of view, it is emitted and then instantaneously reabsorbed. This is true for a photon emitted in the core of the Sun, which might be reabsorbed after crossing a fraction of a millimetre’s distance. And it is equally true for a photon that, from our point of view, has travelled for over 13 billion years after being emitted from the surface of one of the universe’s first stars.

So it seems that not only does a photon not experience the passage of time, it does not experience the passage of distance either. But since you can’t move a massless consciousness at the speed of light in a vacuum, the real point of this thought experiment is to indicate that time and distance are just two apparently different aspects of the same thing. [click to continue…]

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Coming To A Solar System Near You… Super-Earth!

by Tammy Plotner on August 6, 2011

Planetary system of HR 8799 imaged by Marois et al (2010). The central star is of spectral type A with a mass of 1.5 solar-masses at a distance of 128 light-years from the Sun. The planets have the masses of Mb = 7MJ , Mc = Md = 10MJ , and Me = (7?10)MJ , with semimajor axes of 68, 38, 24, and 14.5 AU, respectively. Figure with the permission of NPG.

It is our general understanding of solar system composition that planets fall into two categories: gas giants like Jupiter, Saturn, Neptune and Uranus… and rocky bodies that support some type of atmosphere like Earth, Mars and Venus. However, as we reach further into space we’re beginning to realize the Solar System is pretty unique because it doesn’t have a planetary structure which meets in the middle. But just because we don’t have one doesn’t mean they don’t exist. As a matter of fact, astronomers have found more than 30 of them and they call this new class of planet a "Super-Earth”. [click to continue…]

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