Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry to explain their origin and their overall evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroids, asteroids, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is the branch of astronomy that studies the universe as a whole.

Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Egyptians, Babylonians, Greeks, Indians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars.

Astronomy is one of the few sciences in which amateurs play an active role. This is especially true for the discovery and observation of transient events. Amateur astronomers have helped with many important discoveries, such as finding new comets. (Full article...)

A transit of Venus takes place when Venus passes directly between the Sun and the Earth (or any other superior planet), becoming visible against (and hence obscuring a small portion of) the solar disk. During a transit, Venus is visible as a small black circle moving across the face of the Sun.

Transits of Venus reoccur periodically. A pair of transits takes place eight years apart in December (Gregorian calendar) followed by a gap of 121.5 years, before another pair occurs eight years apart in June, followed by another gap, of 105.5 years. The dates advance by about two days per 243-year cycle. The periodicity is a reflection of the fact that the orbital periods of Earth and Venus are close to 8:13 and 243:395 commensurabilities. The last pairs of transits occurred on 8 June 2004 and 5–6 June 2012. The next pair of transits will occur on 10–11 December 2117 and 8 December 2125. (Full article...)

• ... that Abell 2142, a galaxy cluster, is one of the most massive objects in the universe?
• ... that a jet from one of the component stars of Z Canis Majoris is over 11 light-years long?
• ... that Messier 58 is one of the brightest galaxies in the Virgo Cluster and is 1 of 4 barred spiral galaxies included in Charles Messier's catalog?
• ... that the asteroid 2014 AA entered Earth's atmosphere on the early morning of January 2, 2014, less than a day after it was discovered?
• ... that ATIC, a balloon-borne detector flying over Antarctica, recently found excess cosmic ray electrons that might provide evidence for dark matter consisting of Kaluza-Klein particles?
• .... that the Sun fuses about 620 million metric tons of hydrogen per seconds due to Gravity?

• ... that some exoplanets are evaporating catastrophically?
• ... that examples of artificial planets in science fiction include Riverworld, the Well World, and the Death Star?
• ... that two competing hypotheses seek to explain the unusual orbit of the exoplanet Nu Octantis Ab?
• ... that a group of K-pop fans performed a dance with the goal of convincing a company to commit to 100% renewable energy?
• ... that Carl Grillmair, a Canadian astrophysicist at Caltech, discovered water on multiple exoplanets?
• ... that 1ES 1927+654, a galaxy in Draco, exhibited such extreme nuclear activity that it challenged conventional models of black-hole environments?

PSR B1509−58 is a pulsar approximately 17,000 light-years away in the constellation of Circinus discovered by the Einstein X-Ray Observatory in 1982. X-rays from Chandra are gold; infrared from WISE in red, green and blue/max.

3 March 2026 –

Astronomers announce the discovery 1,900 light-years from Earth of TIC 120362137, the tightest known quadruple star system, using data from NASA's Transiting Exoplanet Survey Satellite. (Space.com)

10 December 2025 – Brazil–China relations

Brazil and China begin constructing a joint laboratory for radio astronomic technology with the Federal University of Campina Grande and the Federal University of Paraíba to support space research as both countries work on the BINGO radio telescope. (Reuters)

• 2 June 1966 – Surveyor 1 lands on the Moon, first US spacecraft to do so
• 3 June 1966 – Gemini 9 (Gemini Titan 9A) launch from Cape Canaveral, Florida
• 19 June 1976 – The Viking 1 orbiter arrives in Mars orbit
• 24 June 2004 – First private spaceflight, SpaceShipOne piloted by Mike Melvill
• 27 June 1996 – Galileo probe, flyby of Ganymede (Jupiter's largest moon)
• 30 June 2001 – The NASA Explorer mission, MAP (Microwave Anisotropy Probe), is launched to measure the temperature of cosmic background radiation (remnant heat from the Big Bang)