Why is a thin crescent moon never seen far from a horizon? Because the only geometry that gives a thin crescent lunar phase occurs when the Moon appears close to the Sun in the sky. The crescent is not caused by the shadow of the Earth, but by seeing only a small part of the […]
What’s causing that unusual ray of light extending from the horizon? Dust orbiting the Sun. At certain times of the year, a band of sun-reflecting dust from the inner Solar System appears prominently after sunset or before sunrise and is called zodiacal light. The dust was emitted mostly from faint Jupiter-family comets and slowly spirals […]
What would make a moon look like a walnut? A strange ridge that circles Saturn’s moon Iapetus’s equator, visible near the bottom of the featured image, makes it appear similar to a popular edible nut. The origin of the ridge remains unknown, though, with hypotheses including ice that welled up from below, a ring that […]
On February 22, a young Moon shared the western sky at sunset with bright planets Venus and Jupiter along the ecliptic plane. The beautiful celestial conjunction was visible around planet Earth. But from some locations Jupiter hid for a while, occulted by the crescent lunar disk. The Solar System’s ruling gas giant was captured here […]
The sun rises on a SpaceX Falcon 9 rocket and Dragon spacecraft on Thursday, Feb. 23, 2023, at NASA’s Kennedy Space Center in Florida. via NASA https://ift.tt/csRdmfw
Planetary nebula Jones-Emberson 1 is the death shroud of a dying Sun-like star. It lies some 1,600 light-years from Earth toward the sharp-eyed constellation Lynx. About 4 light-years across, the expanding remnant of the dying star’s atmosphere was shrugged off into interstellar space, as the star’s central supply of hydrogen and then helium for fusion […]
Astronaut John Glenn enters the Mercury spacecraft, Friendship 7, prior to the launch of Mercury-Atlas 6 (MA-6) on Feb. 20, 1962. via NASA https://ift.tt/lVOMbaP
Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries. Some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy, the island universe is an enormous 200,000 light-years across. Also known as NGC 772, it sports a prominent, outer spiral arm in this detailed cosmic […]
A blue halo glows around Pluto’s receding crescent in this parting image taken by NASA’s New Horizons spacecraft on July 14, 2015. via NASA https://ift.tt/iWVFbmQ
Our Sun is becoming a busy place. Only two years ago, the Sun was emerging from a solar minimum so quiet that months would go by without even a single sunspot. In contrast, already this year and well ahead of schedule, our Sun is unusually active, already nearing solar activity levels seen a decade ago […]