Our star goes through these periods of high and low activity in a variety of cycles. One of the cycles lasts 11 years. When solar activity ramps up in this cycle, it’s called solar maximum — or solar max, for short. We’re coming up to a period of solar max, and the Sun is obliging us with some tremendously cool-looking outbursts. Here’s a movie showing the past few days of activity, courtesy of the SOHO satellite.
Just watch for a while and you’ll see a comet fly by, followed by several outbursts, ending with a huge one this morning that is truly spectacular. Here are a couple of other views of this massive outburst. Sunwatchers are keeping tabs on this outburst — if you have a safe way to observe, check it out! Not sure how much this will influence aurorae yet, but keep an eye out as the Sun continues its ramp up to solar max.
SOHO EIT 304 -- latest image of the Sun, April 13, 2010. SOHO LASCO C3
It’s springtime on Mars and with it comes avalanches near the north polar cap!
The Mars Reconnaissance Orbiter HiRiSE camera team released this spectacular image of an avalanche on Mars. The dust-like particles are hanging a few tens of meters above the surface in a rugged region near the north pole of the Red Planet.
These are likely caused when a avalanche of carbon dioxide frost slide down the steep cliff wall you see here. The cliff itself is about 700 meters (2,000 feet) high and is a melange of layered water ice and dust. It’s very similar to what we see on Earth near our poles (and in fact, reminds me of some snow “dunes” we have near our house that have been piled up since early in the year). The bright stuff on the top surface is ice and frost made of carbon dioxide ice.
The cool thing about this view is that it’s helping the Mars scientists understand the processes that affect the Martian surface throughout the seasons, but especially during the freeze-and-thaw cycle that the planet experiences during late winter into spring. The HiRiSE teams have been spotting avalanches pretty regularly, which gives them a lot to study. They now know that these things come thundering down in the middle of spring — say during the Mars equivalent of April to early May. All together, it seems this is a regular spring process at Mars’s north pole that may be expected every year. Now, all they have to do is figure out the sequence of events that lead to these spectacular events. Stay tuned!
