Photos from EarthSky friends around the world of Sunday evening’s spectacular moon and planet Venus, and Saturday’s moon and Mercury. Thanks to all who submitted or posted to our Facebook page! Miss then? Try again Monday.
Thom Luxford caught the pair from White Rock, British Columbia with an iPhone 5s in panorama mode.
Robot orbiters circling Mars have acquired images of ghost dunes. They’re pits where, scientists believe, tall crescent-shaped sand dunes once existed on this red desert world.
"Ghost dunes" in Noctis Labyrinthus on Mars. The crescent-shaped pits are the remains of active barchan-type dunes from billions of years ago. Image via Mackenzie Day/David Catling/AGU
With the long-running Delta Aquariid meteor shower already in progress, and the moon in a waxing crescent phase – and gone from the sky after midnight – we’re beginning to receive meteor photos.
David S. Brown caught this meteor on July 30, 2014, in southwest Wyoming.
A new infrared instrument on a telescope in Hawaii will let astronomers find more exoplanets orbiting red dwarf stars. The discoveries may include rocky worlds that are potentially habitable.
A test observation by IRD of red dwarf GJ 436. Comparing the star's spectrum (broken line) to the laser frequency comb (dots) allows researchers to calculate the motion of the star. Image via NINS Astrobiology Center.
Last week, scientists announced the 1st known source for ghostly, high-energy neutrinos. The source is a blazar, a billion-solar-mass black hole 3.7 billion light-years away. The discovery establishes a new way to study the universe.
Mysterious ‘Oumuamua is the 1st confirmed interstellar object to pass through our solar system.
Artist impression of the interstellar object ‘Oumuamua. Image via ESA/Hubble, NASA, ESO, M. Kornmesser.
The best time to see Mars since 2003 is now! Watch for Mars as the extremely bright red “star,” ascending in the east by mid-evening and crossing the sky for the rest of the night. Photos from the EarthSky community here.
Mars on July 14, from Johnnyxbox Childers, who wrote: "Bright Mars captured in the wee minutes of Saturday, while practicing new photographic techniques."
Asteroid 2017 YE5 swept by Earth in late June. Turns out, it’s a double asteroid, with both bodies almost identical in size and not touching – only the 4th such object ever detected.
Bi-static radar images of the binary asteroid 2017 YE5 from the Arecibo Observatory and the Green Bank Observatory on June 25. The observations show that the asteroid consists of two separate objects in orbit around each other. Image via Arecibo/GBO/NSF/NASA/JPL-Caltech.
An explanation of why extra-close perigees and extra-far apogees happen at new and full moons.
Diagram via Bedford Astronomy Club
. The line connecting lunar perigee with lunar apogee defines the moon's major axis. At (A) the major axis is pointing directly at the sun, maximizing the eccentricity of the moon's orbit. At this juncture, perigee is less distant and apogee more distant, giving rise to a perigee new moon (supermoon) and an apogee full moon (micro-moon). Then, 3.5 lunar months (103 days) later, at (B), the moon's major axis makes a right angle to the sun-Earth line. This minimizes the eccentricity, lessening the apogee distance yet increasing the perigee distance. Then 7 lunar months (206 days) after the major axis points directly at the sun at (A), it points toward the sun at (C) - except that it's an apogee new moon (micro-moon) and perigee full moon (supermoon). Generally, the closest perigee comes at full moon and the farthest apogee at new moon.