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>
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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>
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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>
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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>
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