As most of you know, when Galileo first observed the Sun with his small telescope, he noticed sunspots. It’s one of the reasons we are celebrating the International Year of Astronomy in 2009, because this was one of Galileo’s observations in 1609. If Galileo were observing the Sun today (NEVER point a telescope directly to the Sun – you need special equipment to do that safely), he would have been disappointed. There were no sunspots visible on the surface (actually photosphere) of the Sun for 78 out of the first 90 days of this year. This has led one NASA solar physicist, Dean Pesnell, to refer to this portion of the Sun’s sunspot cycle as a “deep solar minimum.” To learn more about sunspot cycles and the current solar minimum, read this NASA article online here.
Don’t forget, today starts the 100 Hours of Astronomy, a major effort of the International Year of Astronomy, with participation around the world. Check out the latest, including ESO/ESA participation with Around the World in 80 Telescopes starting here.
In a paper appearing in today’s Nature, astronomers report on evidence which apparently contradicts the current models of the formation of the most massive galaxies. Most astronomers today feel that galaxies initially formed from density anomalies within the emerging universe as indicated by the most recent cosmic microwave background radiation measurements of the WMAP satellite. As stated by these authors “findings suggest a new picture in which brightest cluster galaxies experience an early period of rapid growth rather than prolonged hierarchical assembly.” Read more about the formation of the most massive galaxies in the universe online now here.