Portal:Astronomy

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...)

Composite image using optical images from the HST and X-ray data from the Chandra X-ray Observatory.

The Cat's Eye Nebula (also known as NGC 6543 and Caldwell 6) is a planetary nebula in the northern constellation of Draco, discovered by William Herschel on February 15, 1786. It was the first planetary nebula whose spectrum was investigated by the English amateur astronomer William Huggins, demonstrating that planetary nebulae were gaseous and not stellar in nature. Structurally, the object has had high-resolution images by the Hubble Space Telescope revealing knots, jets, bubbles and complex arcs, being illuminated by the central hot planetary nebula nucleus (PNN). It is a well-studied object that has been observed from radio to X-ray wavelengths. At the centre of the Cat's Eye Nebula is a dying Wolf–Rayet star, the sort of which can be seen in the Webb Telescope's image of WR 124. The Cat's Eye Nebula's central star shines at magnitude +11.4. Hubble Space Telescope images show a sort of dart board pattern of concentric rings emanating outwards from the centre. (Full article...)

• ... that lenticular galaxy NGC 1553 is located at the center of the Dorado Group, and has a spiral feature that is only visible in X-rays?
• ... that giant diffuse galaxies, located in the centre of galaxy clusters, often possess a halo of devoured star matter extending as far out as 3 million light years?
• ... that the giant pulses of PSR B1937+21, the first discovered millisecond pulsar, are the brightest radio emission ever observed?
• ... that the star BX Circini is thought to have formed from the merger of two white dwarfs?
• ... that when astronomer Lacaille originally charted the constellation Caelum, it was recognized as an "engraver's chisel"?
• ... that the gamma-ray burst GRB 080319B was visible to the naked eye even though it was 7.5 billion light year away (z=0.937)?

• ... that Michael Collins has been called "one of the best clarinettists walking the planet" by The Times?
• ... that the majority of extrasolar planets in fiction are inhabited by native species?
• ... that fictional planets of the Solar System include planets between Venus and Earth, planets on the inside of a hollow Earth, and a planet "behind the Earth"?
• ... that the galaxy CDG-2 is over 99.9% dark matter, one of the highest proportions discovered?
• ... that Kim Ye-ji's performance in the 10 meter air pistol at the 2024 Summer Olympics led her to be dubbed the "coolest person on the planet"?
• ... that examples of artificial planets in science fiction include Riverworld, the Well World, and the Death Star?

Active asteroids are small Solar System bodies that have asteroid-like orbits but show comet-like visual characteristics. Image of asteroid (596) Scheila displaying a comet-like appearance on December 12, 2010.

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 April 1968 – The epic science fiction film, 2001: A Space Odyssey is released
• 3 April 2014 – NASA announces that the Cassini orbiter has found evidence of an underground body of water on Enceladus, a moon of Saturn
• 7 April 2001 – Mars Odyssey orbiter is launched to map and search for water on Mars
• 12 April 1961 – Cosmonaut Yuri Gagarin becomes the first human to enter outer space when he is launched into orbital flight in Vostok 1
• 19 April 1971 – The first space station, Salyut 1, is launched into orbit
• 24 April 1990 – The Hubble Space Telescope, a powerful research tool and public relations boon for astronomy, is launched into orbit