Astronomers use many methods to determine this number, including gravitational lensing, the universe’s expansion rate, and more.

Today in the history of astronomy, NASA announces evidence of material being consumed by the black hole at the center of our ...

Planetariums around the world are invited to participate in this year’s edition of the IAU’s annual outreach event.

John Dobson, born in 1915, relocated to San Francisco from Beijing in 1927. Following a period as a monk within the Ramakrishna Order (1944-1967), Dobson cultivated a passion for astronomy. He is ...

August 22nd: The Swan Nebula (M17) reaches its highest point around 11 PM local daylight time, observable with binoculars or telescopes in northwestern Sagittarius. August 23rd: A New Moon, termed a ...

Equuleus, also known as the Foal, is a small and faint constellation located southwest of Pegasus. Unlike many constellations, Equuleus lacks bright stars, nearby stars, prominent meteor showers, or ...

Sound needs a medium (solid, liquid, or gas) to travel. Space is a vacuum, lacking the matter to carry sound waves. No sound in space means no echoes. While a near-perfect vacuum, some sounds can be ...

Temperature is a measure of the average energy of a collection of particles. (This is in contrast to kinetic energy, which is a measure of the energy carried by a single particle.) So, to answer a ...

On August 8th, the close conjunction of the Moon and Pluto will occur, though Pluto's visibility will be obscured by the Moon's brightness. Observation of the double star Albireo in Cygnus is ...

On September 5th, the constellation Camelopardalis, containing Kemble's Cascade and NGC 1502, will be visible in the northern sky after 11 PM local daylight time. Uranus will become stationary on ...

Common visualizations of black holes, like embedding diagrams, inaccurately depict them as funnels with no bottom; this "bottom" represents a misrepresentation of space-time curvature in a simplified, ...

Mars and Spica will appear in close proximity (2° separation) in the evening western sky shortly after sunset, setting before 9 PM local daylight time. Observations of Mars and Spica are best ...