TRAPPIST-1 is a cool red dwarf star with seven known exoplanets. It lies in the constellation Aquarius about 40.66 light-years away from Earth. It has a mass of about 9% of the Sun and is estimated to be 7.6 billion years old, making it older than the Solar System. The discovery of the star was first published in 2000. Observations in 2016 from the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) led to the discovery of two orbiting terrestrial planets, and five more were found in 2017. It takes the seven planets between about 1.5 and 19 days to orbit around the star. They are likely tidally locked to TRAPPIST-1, leading to permanent day on one side and night on the other. Their masses are comparable to that of Earth. Up to four of the planets orbit at distances where temperatures are suitable for the existence of liquid water (diagram pictured), and are thus potentially hospitable to life. This has drawn interest from both researchers and popular culture.

Read more: https://en.wikipedia.org/wiki/TRAPPIST-1

_______________________________ Today's selected anniversaries:

1863:

American Civil War: At the Battle of Big Black River Bridge in Mississippi, Union forces under John A. McClernand defeated a Confederate rearguard and captured around 1,700 men. https://en.wikipedia.org/wiki/Battle_of_Big_Black_River_Bridge

1900:

The first copies of the children's novel The Wonderful Wizard of Oz by L. Frank Baum were printed. https://en.wikipedia.org/wiki/The_Wonderful_Wizard_of_Oz

1954:

The U.S. Supreme Court ruled in the landmark case Brown v. Board of Education, outlawing racial segregation in public schools because "separate educational facilities are inherently unequal" and therefore unconstitutional. https://en.wikipedia.org/wiki/Brown_v._Board_of_Education

1987:

An Iraqi jet fired two Exocet missiles at the American frigate USS Stark, killing 37 personnel and injuring 21 others. https://en.wikipedia.org/wiki/USS_Stark_incident

_____________________________ Wiktionary's word of the day:

T-ray: (electrical engineering, electromagnetism, also attributive, chiefly in the plural) An electromagnetic wave with a frequency intermediate between, and sharing the properties of, short radio waves and long infrared waves, generally in the 0.1 to 10 terahertz (THz) band of frequencies. https://en.wiktionary.org/wiki/T-ray

___________________________ Wikiquote quote of the day:

Child, child, do you not see? For each of us comes a time when we must be more than what we are.   --Lloyd Alexander https://en.wikiquote.org/wiki/Lloyd_Alexander