• J. A. Fleming died, 1945 (b. 1849).

    Illustration from the Bibliographical Memoirs of Fellows of the Royal Society, 1945. The Royal Society, London. Sir John Ambrose Fleming FRS died in 1945, aged 95 (born 29 November 1849). "He was an English electrical engineer and physicist who invented the first thermionic valve or vacuum tube, designed the radio transmitter with which the first […]

  • International Earth Day

    First held in 1970, Earth Day is held annually on April 22 to demonstrate support for environmental protection.

  • Lyrids Meteor Shower

    Peak: ~Apr 21-22, 2020 The Lyrids are a medium strength shower that usually produces good rates for three nights centered on the maximum. These meteors also usually lack persistent trains but can produce fireballs. These meteors are best seen from the northern hemisphere where the radiant is high in the sky at dawn. Activity from […]

  • A Jesuit’s Guide to the Stars: Exploring Wonder, Beauty, and Science

    Church of Saint Thomas More 1079 Summit Avenue, Saint Paul, Minnesota, United States

    Curious about God, the cosmos and you?You can ask the Pope’s astronomer! Come with your curiosity and questions to hear Brother Guy Consolmagno, SJ, 7:00 pm, Thursday, April 24, 2025, at Saint Thomas More Catholic Church In his new book, A Jesuit Guide to the Stars, Brother Guy Consolmagno, SJ, asks, “Do we need to know […]

  • International Chernobyl Disaster Remembrance Day

    An explosion at the Chernobyl Nuclear Power Plant in 1986 spread a radioactive cloud over large parts of the Soviet Union; millions of people in the three countries were exposed to the radiation.

  • New Moon 2025

    New Moon 2025

    New Moon. By the modern definition, New Moon occurs when the Moon and Sun are at the same geocentric ecliptic longitude. The part of the Moon facing us is completely in shadow then. Pictured here is the traditional New Moon, the earliest visible waxing crescent, which signals the start of a new month in many […]

  • World Day for Safety and Health at Work

    The World Day for Safety and Health at Work will focus on addressing the outbreak of infectious diseases at work, in particular, on the COVID-19 pandemic.

  • Cinco de Mayo

    Mother's Day in the United States is an annual holiday celebrated on the second Sunday in May. Mother's Day recognizes mothers, motherhood and maternal bonds in general, as well as the positive contributions that they make to society. It was established by Anna Jarvis, with the first official Mother's Day celebrated through a service of worship at St. Andrew's Methodist […]

  • Mother’s Day (USA)

    Mother's Day in the United States is an annual holiday celebrated on the second Sunday in May. Mother's Day recognizes mothers, motherhood and maternal bonds in general, as well as the positive contributions that they make to society. It was established by Anna Jarvis, with the first official Mother's Day celebrated through a service of worship at St. Andrew's Methodist […]

  • World Metrology Day.

    World Metrology Day is an annual celebration of the signature of the Metre Convention on 20 May 1875 by representatives of seventeen nations. The Convention set the framework for global collaboration in the science of measurement and in its industrial, commercial and societal applications. The original aim of the Metre Convention - the world-wide uniformity […]