Astrophages: How Stars Devour Their Neighbors
Astrophages are stars that absorb material from a companion. We examine examples, observable evidence, and the limits of the term without sensationalism.
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140 itemsMeteor Showers: When to Watch Without a Telescope
You don’t need a telescope to see meteors: dark skies, an open view and the shower’s activity period matter most. Here’s what to look for.
✦ PlanetsSeasons on Earth and Mars: Orbits and Climate
A Martian year lasts 687 Earth days, and Mars’s orbital eccentricity is about five times Earth’s—so its seasons are uneven in length.
Saturn and Its Moons: Titan, Enceladus, and Other Worlds
Titan hides methane lakes beneath its dense atmosphere, while Enceladus ejects water vapor and ice. We compare the composition and activity of Saturn’s moons.
✦ TelescopesLunar Eclipse: Why the Moon Turns Red
Earth’s atmosphere scatters blue light and lets red rays reach the Moon. Find out when to watch an eclipse and how to observe it without a telescope.
✦ TelescopesMoon Phases: A Day-by-Day Observing Calendar
Explore the Moon’s roughly 29.5-day cycle: when to look for craters along the terminator, and when the full Moon and lunar maria are easier to observe.
✦ TelescopesBuying a Telescope for Planets and Stars: How to Choose
Compare aperture and mount when buying a telescope for planets and stars: 70–90 mm suits beginners, while 100–130 mm offers room to grow.
✦ PlanetsEarth and Mars: Comparing Their Internal Structure
Mars’s core radius is estimated at 1,780–1,810 km, while Earth’s mantle extends 2,890 km. Their interiors help explain each planet’s geology.
✦ PlanetsMercury and Venus Near the Horizon: When to Look for Them
Mercury never strays more than 28° from the Sun, so look for it at twilight. Learn whether to choose morning or evening—and why location and a clear horizon mat
✦ PlanetsWhy Mars Is Brighter at Opposition
At opposition, Earth passes between the Sun and Mars, bringing the planet closer and making it appear larger and brighter. But not all oppositions are alike.
✦ Space NewsSpace News Today: How to Verify a Discovery
Space news today: learn what the August 6 spacewalk, August 30 Roman telescope launch and exoplanet discovery confirm—and what they don’t.
✦ Space MissionsSpacecraft Mission Profiles: Flyby, Orbit, and Landing
A spacecraft mission defines its route, scientific objectives, and communications. Compare flyby, orbital study, and landing through the example of Orion.