A globular cluster is a spherical collection of stars that orbits a galaxy core as a satellite. They are tightly bound by gravity, which gives them their spherical shape and relatively high stellar density towards their core. There are more than 150 known globular clusters in the Milky Way, with perhaps many more undiscovered. Large galaxies can have more: Andromeda, for instance, may have as many as 500. Some giant elliptical galaxies, such as M87, may have as many as 10,000 globular clusters. These globular clusters orbit the galaxy out to large radii, 40,000 parsecs or more. Every galaxy of sufficient mass in the Local Group and almost every large galaxy surveyed has an associated system of globular clusters. The Sagittarius Dwarf Spheroidal Galaxy and Canis Major Dwarf Galaxy both appear to be in the process of donating their associated globular clusters to the Milky Way, such as Palomar 12.
Read more: https://en.wikipedia.org/wiki/Globular_cluster
_______________________________ Today's selected anniversaries:
1645:
English Civil War: The Parliamentarians destroyed the last Royalist field army at the Battle of Langport, ultimately giving Parliament control of the west of England. https://en.wikipedia.org/wiki/Battle_of_Langport
1942:
An American naval aviator discovered a downed Mitsubishi A6M Zero on Akutan Island, Alaska, which was later rebuilt and flown to devise tactics against that type of aircraft. https://en.wikipedia.org/wiki/Akutan_Zero
2011:
The last edition of the British tabloid News of the World was published, closing due to allegations that it hacked the voicemails of murdered schoolgirl Milly Dowler, victims of the 7/7 attacks and relatives of deceased British soldiers. https://en.wikipedia.org/wiki/News_International_phone_hacking_scandal
_____________________________ Wiktionary's word of the day:
sortie: 1. (military, also attributively and figuratively) 2. An attack made by troops from a besieged position; a sally. 3. (aviation) An operational flight carried out by a single military aircraft. 4. (by extension) 5. An act of venturing out to do a task, etc. 6. (figuratively) 7. An act of trying to enter a new field of activity. 8. (sports) An attacking move. 9. (astronautics) An operational flight carried out by a spacecraft involving a return to Earth. 10. (military) Synonym of sally port (“an entry to or opening into a fortification to enable a sally”) 11. (photography) A series of aerial photographs taken during the flight of an aircraft; (by extension) a photography session. 12. (intransitive) To carry out a sortie; to sally. https://en.wiktionary.org/wiki/sortie
___________________________ Wikiquote quote of the day:
The time which we have at our disposal every day is elastic; the passions that we feel expand it, those that we inspire contract it; and habit fills up what remains. --Marcel Proust https://en.wikiquote.org/wiki/Marcel_Proust