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Copy, Moon Joy
Carrying the torch from Apollo, through shuttle and station, to a hoped-for new era of space exploration, the Artemis 2 lunar flyby exceeded expectations All last week, I monitored the NASA mission coverage livestream. As the crew approached the Moon (Luna), it waned from gibbous to half to crescent in just a few hours, as…
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The Dream Is Alive
As a child of the Apollo program and a lifelong dreamer of spaceflight, I am thrilled to follow the Artemis 2 mission, carrying the first humans around the Moon (Luna) in over half a century, with the intent to pick up where we left off, establish a permanent lunar presence, and proceed to Mars and…
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Barred Warped Wobbly Spiral
Advances in astronomy can rewrite even introductory textbooks. Although no spacecraft have yet exited our Milky Way galaxy to image it from the outside, the Gaia astrometry space telescope recently completed a dozen years of accurately measuring the positions, distances, and motions of billions of Milky Way stars from a Lissajou orbit about the Earth–Sun…
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Blue Ghost Eclipse
Last night’s lunar eclipse, as seen from Earth, looked like a solar eclipse, as seen from Luna. Firefly Aerospace‘s NASA-funded Blue Ghost lunar lander recently became the first commercial spacecraft to successfully land on Earth’s moon Luna. Blue Ghost’s mission is designed to last a single lunar day, about two terrestrial weeks. Last night it…
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Mount Wilson Trek
Nobody walks in L.A., but as a Caltech grad student without a car in the mid 1980s, I once walked from my dorm room up Mount Wilson and touched the enclosure of the famous 100-inch (2.54-meter) Hooker telescope, for 32 years, the world’s largest, where Hubble discovered that the Andromeda “nebula” was actually a galaxy…
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Outer Planet Cloud Colors
From my teens to my twenties, from junior high school to graduate school to young professor, I excitingly followed the first reconnaissance of the outer solar system by the Pioneer and Voyager spacecraft. But the exploration isn’t over. For the last decade, the Hubble Space Telescope has been systematically observing the colors and dynamics of…
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Where Are the Stars?
When viewing space photography, such as Apollo or International Space Station photos, people often ask, “Where are the stars?” Typically such photos properly expose the bright lunar or space station surfaces and consequently underexpose the dim background stars, rendering space as featureless black. Current ISS astronaut Matthew Dominick has been experimenting with photography, and his…
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Measuring the Solar System
Thousands of years ago, ancient astronomers like Aristarchus and Eratosthenes combined careful observations with simple mathematics to measure the solar system, especially the diameters D of Earth, Luna (Earth’s moon), Sol (Earth’s star, the sun), and the radii r of their orbits. You too can do this, but it helps to observe an eclipse or two.…
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The Ringed Planets
When I was a kid, Saturn was the ringed planet. But today, we know that all of the outer planets have rings. The James Webb Space Telescope has now imaged each of them in infrared revealing their distinctive structures, including Jupiter‘s very faint ring (located by the arrow and dashed curve). The planet images below…
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Compton Generator
Long before he won the Nobel Prize in Physics, and while still a Wooster undergraduate, Arthur Compton realized a third way to demonstrate Earth’s spin (after pendulums and gyroscopes). Compton reported his results in a manuscript submitted to the journal Science on 1913 January 13 and published as “A Laboratory Method of Demonstrating the Earth’s Rotation”,…

Thanks, Mark! I enjoy reading your posts as well.