If you happened upon this blog, it’s either because you’re wildly lost, or you dig spacey-sciency stuff like astronomy, Star Trek, and pretty much everything Neil deGrasse Tyson has ever said. So if you’re in the latter group, and you’re also on Twitter, check me out tomorrow during the WORLD PREMIER OF COSMOS for some (hopefully) clever and (almost certainly) nerdy commentary on Fox’s new series.
Mars’ northern-most sand dunes are beginning to emerge from their winter cover of seasonal carbon dioxide (dry) ice. Dark, bare south-facing slopes are soaking up the warmth of the sun.
The steep lee sides of the dunes are also ice-free along the crest, allowing sand to slide down the dune. Dark splotches are places where ice cracked earlier in spring, releasing sand. Soon the dunes will be completely bare and all signs of spring activity will be gone.
Dramatic prominences can sometimes be seen looming just beyond the edge of the sun. Such was the case last week as a large prominence, visible above, highlighted a highly active recent Sun. A waving sea of hot gas is visible in the foreground chromosphere in great detail as it was imaged in one specific color of light emitted by hydrogen. A solar prominence is a cloud of solar gas held just above the surface by the Sun’s magnetic field. The Earth, illustrated in the inset, is smaller than the prominence. Although very hot, prominences typically appear dark when viewed against the Sun, since they are slightly cooler than the photosphere below them. A quiescent prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System, some of which may strike the Earth and trigger auroras.