THE SOUTHWORTH PLANETARIUM 207-780-4249 www.usm.maine.edu/planet <http://www.google.com/url?q=http%3A%2F%2Fwww.usm.maine.edu%2Fplanet&sa=D&sntz=1&usg=AFQjCNHulkHuLP13bOG2PkNrPazsGWFs2A> 70 Falmouth Street Portland, Maine 04103 43.6667° N 70.2667° W Altitude: 10 feet below sea level Founded January 1970 Julian Date: 245907.16 2019-2020: CVI "I'm no rocket surgeon." -seen on a bumper sticker. THE DAILY ASTRONOMER Thursday, Feb 27, 2020 Mini-Moon! First, the great news! Earth has a brand new moon, not to be confused with the "New moon," defined as the moon-Sun alignment that places the moon between the Sun and Earth. Second, the less-than-great news One will not be able to observe this brand new moon in the sky, much to the chagrin of the incurable romantics who can never get sufficient quantities of moon light. This new moon is a "mini moon," a teeny little asteroid measuring 6 feet by 11 feet: something that could pack a punch to a person who came to cross purposes with it, but poses no threat to the planet. Dubbed 2020 CD3*, this tumbling rock likely ventured too close to Earth about three years ago and became temporarily ensnared by its gravity. Like asteroid 2006 RH120, the only other captured mini-moon yet identified, it will likely loiter about the world for a spell before careening back into interplanetary space. Earth captured 2006 RH120 in June 2006 and it escaped in September 2007. How long we'll retain this new mini moon is anybody's over educated guess. Because this mini moon is so absurdly small it is well below the threshold of naked eye visibility. At a magnitude of 20 it is nearly 400,000 times dimmer than the faintest star visible without a telescope. Nothing that could silver coat a half decent forest. 2002 CD3 isn't the first of Earth's mini-moons and certainly won't be the last. The planet has probably been the temporary host to millions of mini moons through its long life. Astronomers are naturally delighted at the discovery of this latest interloper. It pleases us all to know that a few of the myriad asteroids swarming around the solar system occasionally takes a spin around Earth: a reminder that our neighborhood is abuzz with activity. As though we could ever forget that fact! *The name seems terribly complex. Happily, it isn't really. Those numbers/letters are assigned to an asteroid based on the time of its discovery. The first number is the discovery year, in this case 2020. The first letter refers to the half month of its discovery. The year is divided into half months: Jan 1 - 15 is A; Jan 16 - 31 B; Feb 1 - 15 C; Feb 16 - 29 D; et cetera. (I and Z are omitted). The second letter indicates the order of discovery, so the first body discovered in that half month would be assigned A, the second B, the third C. However, as so many bodies are discovered each half month, the third number indicates the number of cycles for the second letter. For instance, 2020 CA would be the first body discovered in the half month beginning Feb 1st. 2020 CA1 would be the 26th body discovered in that same half month. (The letter I is omitted as it closely resembles the number 1.) 2020 CD3 was discovered on Feb 15, 2020 and was the 79th object discovered in that half month. To subscribe or unsubscribe from the Daily Astronomer: https://lists.maine.edu/cgi-bin/wa?SUBED1=DAILY-ASTRONOMER&A=1