FreeSky Cosmos

When Edward Emerson Barnard peered through the 36-inch refractor at Lick Observatory on Sept. 9, 1892, and spotted Amalthea, it marked the first discovery of a moon of Jupiter in 280 years. Galileo had discovered the four largest jovian moons – Io, Europa, Gan... [Verified by Editorial Desk.]

Looking for a sky event this week? Check out our full Sky This Week column.  September 8: The Moon joins Jupiter The waning Moon has moved from Cancer to Leo and is nearing the bright star Regulus, which marks the Lion’s heart. Our satellite will pass 0.6° sou...

On Sept. 8, 2016, the Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer (OSIRIS-REx) mission launched from Cape Canaveral, setting off on its 4.4-billion-mile (2 billion kilometers) journey to asteroid Bennu. About the...

Looking for a sky event this week? Check out our full Sky This Week column.  September 7: Venus and Spica, side by side The Moon has now skimmed through the morning sky over to Cancer, where it checks in on Jupiter — and you can check in on them both before da...

If you visit the New Horizons mission website frequently, you'll notice that the spacecraft continues to generate excellent science as it plows its way through the Kuiper Belt. It recently woke up from its latest hibernation period in good health and is transm...

Extreme quasars near the dawn of time are giving astrophysicists clues to the formation of supermassive black holes....

The Moon is busy in September. Coming off of eclipse season in August, the Moon visits no less than two planets, two bright stars and one open cluster in September, as it heads towards the Full Harvest Moon of 2026 on September 26th. No matter where on Earth y...

Cross-disciplinary research at Perimeter Institute and University of Maryland shows that dark photons could be lurking in more places than previously thought....

Born in Kath, Khwarezm – a region that today would be cover parts of Uzbekistan, Kazakhstan, and Turkmenistan – Abu Raihan Muhammad al-Biruni was a man of many scientific talents. His extensive travels throughout the Middle East and modern India and his self-e...

Mark Johnston from Scottsdale, Arizona On Aug. 21, 2026, an unusually long-lasting M-class flare erupted from a sunspot group near the Sun’s west limb. As the flare’s stretched magnetic field lines reconnected and relaxed, they filled with hot plasma that cool...

The phenomenon of a Full Moon arises when our planet, Earth, is precisely sandwiched between the Sun and the Moon. This alignment ensures the entire side of the Moon that faces us gleams under sunlight. Thanks to the Moon’s orbit around Earth, the angle of sun...