When you plot the position of Mars in the sky, you’ll notice that in general it moves from West to East. But when we are closest to Mars, it seems to go backwards for a bit before continuing. This is called retrograde motion, and this challenged early models of the Solar system which had Earth at the centre. The animation shows why Mars appears to go backwards for a bit. [more] [code]
NASA funded observations on the W. M. Keck Observatory, with analysis led by the Univ. of Leicester, tracked the “rain” of charged water particles into the atmosphere of Saturn and found the extent of the ring-rain is far greater, and falls across larger areas of the planet, than previously thought. The work reveals the rain influences the composition and temperature structure of parts of Saturn’s upper atmosphere. The paper appears in this week’s issue of the journal Nature.
Images must be woven together from the incoming data from the cameras, cleaned up and given colors that bring out features that eyes would otherwise miss. In this video from HubbleSite, a Hubble-imaged galaxy comes together on the screen.
They’re not just ‘pretty space pics’ there is a lot of work going on before the end result. And this is an idea of how it happens.
Saturn’s north polar hexagon basks in the Sun’s light now that spring has come to the northern hemisphere. Many smaller storms dot the north polar region and Saturn’s signature rings put in an appearance in the background.
Many galaxies appear to have stronger gravity - and thus more mass - than can be explained by their visible matter alone. Overly massive galaxies are most often attributed to dark matter, an invisible substance that interacts with matter through gravity. To date, though, no one has directly detected dark matter particles.