THE SOUTHWORTH PLANETARIUM 70 Falmouth Street Portland, Maine 04103 (207) 780-4249 usm.maine.edu/planet 43.6667° N 70.2667° W Altitude: 10 feet below sea level Founded January 1970 2021-2022: LXVII "All that we see or seem is but a dream within a dream." -Edgar Allan Poe (born on this day in 1809, exactly 134 years before Janis Joplin.) THE DAILY ASTRONOMER Wednesday, January 19, 2022 4800! During the period of time you require to read this entire sentence, the Universe will have added nearly 20,000 stars to its already burgeoning stellar population. By this statement we mean that about 20,000 stars will initiate the intensely powerful thermonuclear fusion processes that sustain stars through their life cycles. That value equals about 4,800 stars every single second! Or, a night sky's worth of stars every 2.1 seconds. Our minds, which instinctively shy away from the unfathomably disproportionate, might envision so much diamond dust scattered along dark velvet. Instead, almost five thousand new suns come on-line every time we blink! That value likely almost includes five thousand solar systems replete with planets, moons and a wide variety of asteroidal, cometary and other extraneous flotsam. (Yes, these bodies will also be found in binary and other multiple systems.) How many of these systems will produce conditions conducive to life's development is truly anybody's guess. Even if only one tenth of one-percent of these systems give rise to life, the cosmos will add about five life-bearing worlds to its census every second, or 432,000 every single Earth day, Kirk! Mind you, the stars that snap on now won't be shining down on creatures for quite some time, if our own natural history is any indication. Nevertheless, the process might still be starting...and how! This grand statements are all very well and truly stagger the imagination. However, how can one arrive at this figure? We certainly can't witness all these births. Astronomers have made this determination through extrapolation: observations of star birth in our own galaxy, which amounts to about 3-5 solar masses of material incorporated into active stars every year. However, since approximately 88 percent of stars are smaller than the Sun, this material generally forms more than three to five stars. Most, if not all, spiral galaxies are, like the Milky Way, prodigious star generators. Some of them can even produce a few hundred stars a year. And, spiral galaxies comprise about 72 percent of all the 125-plus galaxies in the observable Universe. Seventy two percent of 125 billion is.....hold on.....about 90 billion spiral galaxies. Add to this value the star birth occuring in other galaxy types,* and one can well understand how so many stars can be born every second. [image: 110601-MilkyWayPhoto-hmed-0825a.jpg] Spiral galaxies such as NGC 6744, a galaxy that closely resembles our own Milky Way, are regions of prodigious star birth. This stellar proliferation bodes well for those of us who believe that the Universe teems with life. Most stars are less massive than the Sun and consequently have longer life-cycles. Red dwarfs, the most common type of stars, can live 1- 3 trillion years. Plenty of time for life to develop and evolve. Again, that assumption is based our own experience, which could be completely different from that of other worlds. We'll find out eventually. For now, we derive comfort from knowing that every day millions of stars light their first sparks in the cosmos. *Star birth rates are very low or even nil in some galaxies, including many gas-poor ellipticals. To subscribe or unsubscribe from the Daily Astronomer: https://lists.maine.edu/cgi-bin/wa?SUBED1=DAILY-ASTRONOMER&A=1