Wikipedia:Main Page history/2019 March 15

the free encyclopedia that anyone can edit.

From today's featured article

Planar transmission lines are flat, ribbon-shaped transmission lines with conductors, or in some cases dielectric (insulating) strips. They are used to interconnect components on printed circuits and integrated circuits working at microwave frequencies, since the planar lines are suited to the manufacturing methods for these components. Transmission line theory is used when the line is longer than a large fraction of a wavelength. At microwave frequencies, this distance is measured in millimetres, which is small enough that these lines can be used for constructing components as well as interconnecting them. The cross-section of the line is usually kept constant so that its electrical behaviour is highly predictable. The first planar transmission line, stripline, was conceived during World War II by Robert M. Barrett; other types in modern use include microstrip, suspended stripline, and coplanar waveguide. (Full article...)

Recently featured:

Did you know...

Oriente warbler

... that until 2002, researchers thought that the two species of Cuban warblers (Oriente warbler pictured) belonged in the New World warbler family?
... that future Phoenix mayor James D. Monihon's regiment was attacked by an estimated 450 Apaches led by chief Cochise during the American Civil War?
... that a 2016 Japanese light novel series received praise for its unique protagonist, who is a vending machine?
... that the conductor Marc Piollet recorded rarely performed symphonies by Norbert Burgmüller and Hugo Staehle, and a DVD of Carmen staged by Calixto Bieito?
... that the U.S. Public Health Service can hire – but not fire – scientists "without regard to the civil-service laws" using a Title 42 appointment?
... that Swiss businessman Cesar Lüthi pioneered the use of revolving billboards in sports marketing?
... that fossils found at Granton Shrimp Bed provided evidence of the structure of conodonts?
... that researchers Eileen Shore and Frederick Kaplan discovered the mutation responsible for a disease that turns muscle into bone?

In the news

Ethiopian Airlines aircraft ET-AVJ in February 2019

At least 49 people are killed in shootings at two mosques in Christchurch, New Zealand.
Following the crash of Ethiopian Airlines Flight 302 (aircraft pictured) with the loss of all 157 people on board, Boeing 737 MAX aircraft are grounded worldwide.
A severe tornado outbreak hits the Southeastern United States, with one tornado causing 23 deaths in Alabama.

On this day

March 15: Ides of March

2015 Women's Boat Race

1147 – Portuguese troops under the leadership of Afonso I captured the Almoravid city of Santarém.
1783 – A potential uprising in Newburgh, New York, was defused when George Washington asked Continental Army officers to support the supremacy of Congress.
1927 – In rowing, Oxford defeated Cambridge in the first Women's Boat Race (2015 edition pictured) held in Oxford, England.
1951 – The Iranian oil industry was nationalized in a movement led by Mohammad Mosaddegh.
2011 – Arab Spring: Protests erupted across Syria against the authoritarian government, marking the start of the Syrian Civil War.

Albert of Schwarzburg (d. 1327) · Johan Vaaler (b. 1866) · Lauren Ebsary (b. 1983)

More anniversaries:

From today's featured list

Abby Wambach

Retired professional soccer player Abby Wambach scored 184 goals in 255 appearances for the United States women's national soccer team, and holds the world record for goals scored at the international level by an individual player, female or male. Wambach broke previous record holder Mia Hamm's record on June 20, 2013, as she completed a hat trick against South Korea, in a friendly match. Wambach scored her first international goal in the seventh minute of a friendly against Finland on April 27, 2002, in her second game for the national team. She scored her first international hat trick during a friendly against Scotland, leading the national team to an 8–2 win in her fourth appearance for the team. Wambach completed her international career having scored a total of 14 goals in her 25 World Cup match appearances, placing second on the all-time World Cup scoring list behind Marta. (Full list...)

Recently featured:

Today's featured picture

Woman Reading a Letter is an oil-on-canvas painting by the Dutch painter Johannes Vermeer, produced in around 1663. The central element of the painting is a woman in blue standing in front of an unseen window, reading a letter. The woman appears to be pregnant, although as pregnancy was rarely depicted in art during this period, some scholars have argued that the woman's rounded figure is simply a result of the fashions of the day. While the contents of the letter are not depicted, the composition of the painting is revealing. The map of the Netherlands on the wall behind the woman has been interpreted as suggesting that the letter she reads was written by a traveling husband. Alternatively, the box of pearls barely visible on the table before the woman might suggest a lover, as pearls are sometimes a symbol of vanity. The painting is unique among Vermeer's interiors in that no fragment of corner, wall or ceiling can be seen. Part of the collection of the city of Amsterdam as part of the Van der Hoop bequest, it has been in the Rijksmuseum since its inception, and was thus the first Vermeer they acquired.

Painting: Johannes Vermeer

Recently featured:

Other areas of Wikipedia

Community portal – Bulletin board, projects, resources and activities covering a wide range of Wikipedia areas.
Help desk – Ask questions about using Wikipedia.
Local embassy – For Wikipedia-related communication in languages other than English.
Reference desk – Serving as virtual librarians, Wikipedia volunteers tackle your questions on a wide range of subjects.
Site news – Announcements, updates, articles and press releases on Wikipedia and the Wikimedia Foundation.
Village pump – For discussions about Wikipedia itself, including areas for technical issues and policies.