Space

Sixty-six million years ago, Earth was a tropical greenhouse. Today, it’s an ice-capped world. And an international team of experts led by the University of Southampton think they know why. Their new study shows that Earth’s massive drop in temperature after the dinosaurs went extinct could have been caused by a large drop in calcium levels in the ocean. The study showed that the dramatic calcium shiftContinue reading “Why did Earth’s greenhouse age end?”

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Massive stars have an outsized influence on their environment and the galaxies they call home. These behemoths have the highest surface temperatures of any normal stars, so they emit copious amounts of ultraviolet radiation that ionizes their surroundings. They also possess fierce stellar winds that help shape their gaseous environs. But these monster suns alsoContinue reading “New JWST imagery dives into the center of the Milky Way”

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The first piloted Apollo flight – called Apollo 204, though it would later be known as Apollo 1 – was intended for tests in Earth orbit, part of the eventual path to later Apollo missions going to the Moon. The mission was crewed by Gus Grissom, America’s second man in space; Ed White, the country’sContinue reading “Jan. 27, 1967: The Apollo 1 fire”

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The September 2025 issue featured “A guide to beginner’s guides,” a reminiscence and description of some the books for astronomy beginners that Contributing Editor Raymond Shubinski recommends or considers influential. Our readers responded with a flood of emails adding their own suggestions to his list. Is your favorite mentioned here? What books are we stillContinue reading “Our readers’ favorite beginner astronomy books”

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Over eight years after its launch, Voyager 2 made its closest approach to Uranus on Jan. 24, 1986. The encounter and data-gathering was complicated by Uranus’ 98-degree axial tilt and the low light levels, but the spacecraft was able to pass by at about 50,600 miles (over 81,400 kilometers) above the cloud tops. Many uniqueContinue reading “Jan. 24, 1986: Voyager 2 flies by Uranus”

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When Pioneer 10 flew by Jupiter on Dec. 3, 1973, its margin of survival was closer to the knife-edge than it seemed. It absorbed a thousand times the lethal dose of radiation for a human, suffering darkened optics and fried transistor circuits. Other unwanted side effects included the generation of false commands, which caused theContinue reading “Jan. 23, 2003: Pioneer 10’s last words”

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Sky This Week is brought to you in part by Celestron. Friday, January 9Cygnus may be sinking toward the horizon a few hours after sunset, but there’s still a bit of time to glimpse some of this constellation’s many treasures. Today let’s try for M39, a loose open cluster in the northeastern reaches of theContinue reading “The Sky This Week from January 16 to 23: Caroline’s Rose blooms”

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Stephen Kane, a professor of planetary astrophysics at UC Riverside, was skeptical when he read recent studies that showed the gravitational pull from Mars being connected to Earth’s long-term climate patterns. These studies suggested that sediment layers on the floor of our oceans have recorded climate cycles influenced by the Red Planet despite its distanceContinue reading “Has Mars had an effect on Earth’s climate?”

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In March of 1781, William Herschel spotted the seventh-known planet of our solar system. He wanted to name it Georgium sidus (George’s star), after King George III. Astronomers outside the U.K. weren’t keen on the planet being named for the British monarch, and recommended sticking with the tradition of naming planets for mythical characters; itContinue reading “Jan. 11, 1787: William Herschel discovers two moons of Uranus”

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You’ll find this terrific open cluster midway between 5th-magnitude Sigma Cassiopeiae and 6th-magnitude Rho Cas. This group glows at magnitude 6.7, so even through a 4-inch telescope, you’ll see 50 stars evenly spread across this rich cluster’s face. An 8-inch telescope shows more than a hundred members and the number just keeps increasing with aperture.Continue reading “Michael’s Miscellany: Observe Herschel’s Spiral Cluster”

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NASA’s Discovery Program, begun in the 1990s and continuing today with missions like Lucy and Psyche, is focused on frequent, cost-effective investigations of our solar system. Its first mission launched in 1996 to near-Earth asteroid Shoemaker; the second mission was the Mars Pathfinder mission, also launched in 1996. On Jan. 6, 1998, the third missionContinue reading “Jan. 6, 1998: Lunar Prospector launches”

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In this episode, Astronomy magazine Editor Emeritus Dave Eicher invites you to head out in the evening of January 6 and find the Moon. Near Luna, glowing at magnitude 1.3, will be Regulus, the Alpha star of the constellation Leo the Lion. The distances between these two objects will change hourly, so maybe check them several times thatContinue reading “This Week in Astronomy with Dave Eicher: The Moon encounters Regulus”

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Though a banker by profession, Wilhelm Beer, who was born Jan. 4, 1797, in Germany, dedicated his life to astronomy, establishing a private observatory in Berlin and acting as a patron and collaborator to professional astronomer Johann Madler. Between 1834 and 1836, Beer and Madler created and published Mappa Selenographica, the most complete and correctContinue reading “Jan. 4, 1797: The birth of Wilhelm Beer”

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The Spirit rover landed on Mars on Jan. 4, 2004. Like its twin, Opportunity, Spirit was assigned an initial mission of only 90 sols. It exceeded this mission lifetime by more than 20 times, delivering invaluable science as it explored the Red Planet. It made its home in Gusev Crater, an ancient impact site andContinue reading “Jan. 3, 2004: Spirit lands on Mars”

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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 sunlight hitting the lunar surface and being reflected back toContinue reading “2026 Full Moon calendar: When to see the Full Moon and phases”

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If you have access to an 8-inch or larger telescope, look in the northern part of the constellation Andromeda the Princessfor a planetary nebula called the Blue Snowball. Insert an eyepiece that will give you a magnification around 100x, and you’ll see immediately why astronomers gave it that name. Specifically, point your scope roughly 4½° east of the magnitudeContinue reading “Michael’s Miscellany: Observe the Blue Snowball”

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Starlight and stardust are not enough to drive the powerful winds of giant stars, transporting the building blocks of life through our galaxy. That’s the conclusion of a new study published in Astronomy & Astrophysics. The team, from Chalmers University of Technology, Sweden, focused on the star R Doradus. Its result overturns a long-held ideaContinue reading “How did the atoms needed for life get into space?”

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