Herbig–Haro objects are bright nebular patches formed when narrow jets of partially ionized gas ejected from newborn stars collide with clouds of gas and dust. Often aligned with a star's rotational axis, they are commonly found in star-forming regions. Most of them lie within a few light-years of the source. They are transient phenomena, lasting around a few tens of thousands of years. They can change visibly over just a few years, as they move rapidly away from their parent star. First observed in the late 19th century by Sherburne Wesley Burnham, Herbig–Haro objects were not recognized as distinct from other emission nebulas until the 1940s. The first astronomers to study them in detail were George Herbig and Guillermo Haro, who independently recognized that the objects were by-products of the star formation process. Although the objects emit visible wavelengths, many are hidden by dust and gas, and can only be seen at infrared wavelengths.

Read more: https://en.wikipedia.org/wiki/Herbig%E2%80%93Haro_object

_______________________________ Today's selected anniversaries:

1776:

American Revolutionary War: The Great Fire of New York (depiction shown) broke out during the British occupation of New York City, destroying up to 1,000 buildings. https://en.wikipedia.org/wiki/Great_Fire_of_New_York_%281776%29

1939:

Romanian prime minister Armand Călinescu was assassinated in Bucharest by pro-Nazi members of the Iron Guard. https://en.wikipedia.org/wiki/Armand_C%C4%83linescu

1968:

The Soviet Zond 5 spacecraft landed in the Indian Ocean, becoming the first to safely return to Earth after circling the Moon. https://en.wikipedia.org/wiki/Zond_5

1999:

A 7.6 Mw earthquake struck Jiji, Taiwan, killing 2,416 people, injuring over 11,000 others and causing about NT$300 billion in damage across the island. https://en.wikipedia.org/wiki/1999_Jiji_earthquake

_____________________________ Wiktionary's word of the day:

venereal: 1. Of or relating to the genitals or sexual intercourse. 2. Of a disease: sexually transmitted; of or relating to, or adapted to the cure of, a venereal disease. 3. (astrology, obsolete) Pertaining to the astrological influence of the planet Venus; lascivious, lustful. 4. (chemistry, obsolete) Of or relating to copper (formerly called Venus by alchemists). https://en.wiktionary.org/wiki/venereal

___________________________ Wikiquote quote of the day:

You couldn't get hold of the things you'd done and turn them right again. Such a power might be given to the gods, but it was not given to women and men, and that was probably a good thing. Had it been otherwise, people would probably die of old age still trying to rewrite their teens.   --Stephen King https://en.wikiquote.org/wiki/Stephen_King