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What Do You Call a Galaxy Without Stars?
To dark matter and dark energy, add dark galaxies — collections of stars so sparse and faint that they are all but invisible. What do you call a galaxy without stars? Earlier this month, radio astronomers announced that they had discovered the darkest galaxy ever not quite seen, a cloud of hydrogen gas resembling our…
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Vampire black hole is a ‘cosmic particle accelerator’ that may solve a longstanding astronomy mystery
Scientists may have found evidence that vampire black holes feeding on their victim stars — so-called microquasars — are the cosmic particle accelerators responsible for mysterious high-energy cosmic rays we see bombarding Earth. These stellar mass black holes exist in binary systems with a supergiant star from which they greedily strip material. Some of that…
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Japan’s lunar lander falls head over heels for the Moon
Touch down: an image of the Smart Lander for Investigating Moon taken by the Lunar Excursion Vehicle-2 shows the craft landed on its nose (Courtesy: JAXA) The Japanese Space Agency, JAXA, has today announced a possible explanation for why its lunar lander is unable to generate power from its solar panels – the craft landed…
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That Famous Black Hole Gets a Second Look
Repeated studies of the supermassive black hole in the galaxy Messier 87 confirm that it continues to act as Einstein’s theory predicted it would. Hello darkness, our old friend, we’ve come to stare at you again. At the center of Messier 87, a giant galaxy 55 million light-years from Earth, is a darkness 24 billion…
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Galileo’s Observations of the Moon, Jupiter, Venus and the Sun
3 min read Born in 1564, Italian astronomer Galileo Galilei’s observations of our solar system and the Milky Way have revolutionized our understanding of our place in the Universe. Galileo sparked the birth of modern astronomy with his observations of the Moon, phases of Venus, moons around Jupiter, sunspots, and the news that seemingly countless…
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What is time? An astronomer explains
Quantum entanglement — when the states of two particle are intertwined by the laws of quantum mechanics — has long vexed physicists. But the phenomenon may also hold the key to understanding how time emerged. Credit: J Jurik Peter/Shutterstock (This article was originally published in the May 2022 issue of Astronomy). St. Augustine said of…
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Retrograde motion explained: what is retrograde motion in astronomy
Why do planets sometimes seem to move “backward”? Is such a motion even real? Should you fear Mercury retrograde? You’ll find answers to these questions in our article. Contents You can also check out our infographic, where we explain how retrograde motion works. Want to know what causes the apparent retrograde motion of the planets?…
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Royal Observatory
Greenwich Outrage 130th anniversary event Join us for a panel discussion with academics, writers and broadcasters about the Greenwich Outrage, followed by a screening of Alfred Hitchcock’s Sabotage, which was loosely inspired by the incident
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JWST catches galactic ‘cat’s tail’ in Beta Pictoris system
An image of the cat’s tail found in the Beta Pictoris system. The black shadow seen in the middle of the image is a coronagraph and was used to block out the central star’s brightness. Credit: NASA, ESA, CSA, STScI, Christopher Stark (NASA-GSFC), Kellen Lawson (NASA-GSFC), Jens Kammerer (ESO), Marshall Perrin (STScI) Beta Pictoris, a…
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The Magellanic Clouds: astronomers make the case for a name change
The Magellanic Clouds are prominent features of the southern sky that are named after the Portuguese explorer Ferdinand Magellan. He sailed west from Europe to the Philippines in the early 16th century and the clouds were described by a returning crew member. Voyages such as Magellan’s set into motion the European colonization of much of…