Planetary Picture of the Day
Week of April 28, 2025
This week, we spied objects from a distance with MRO seeing Curiosity, Hubble capturing a couple of unusual nebulae, and NASA's Juno spying the shadow of Ganymede.
Monday, 28 April 2025
NASA Orbiter Spots Curiosity Rover
NASA’s Curiosity rover appears as a dark speck in this contrast-enhanced view captured on Feb. 28, 2025, by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter. Trailing Curiosity are the rover’s tracks, which can linger on the Martian surface for months before being erased by the wind.
Tuesday, 29 April 2025
Rosette Nebula
This is a Hubble Space Telescope image of a small portion of the Rosette Nebula, a vast star-forming region spanning approximately 100 light-years and located 5,200 light-years away. Hubble zooms into a small portion of the nebula that is only 4 light-years across (the approximate distance between our Sun and the neighbouring Alpha Centauri star system).
Dark clouds of hydrogen gas laced with dust are silhouetted across the image. The clouds are being eroded and shaped by the seething radiation from the cluster of larger stars at the center of the nebula (NGC 2440). An embedded star, visible at the tip of a dark cloud in the upper right portion of the image, is launching jets of plasma that are crashing into the surrounding cold cloud. The resulting shock wave is causing a red glow. The colors come from the presence of hydrogen, oxygen, and nitrogen.
Wednesday, 30 April 2025
Spirograph Nebula
Dubbed the Spirograph Nebula for its resemblance to drawings from a cyclical drawing tool, planetary nebula IC 418 shows poorly understood patterns. Perhaps they are related to chaotic winds from the variable central star, which changes brightness unpredictably in just a few hours.
IC 418 was probably a common red giant star only a few thousand years ago. Since running out of nuclear fuel, the outer envelope has begun expanding outward, leaving a hot remnant core destined to become a white-dwarf star, visible at the image center. The light from the central core excites surrounding atoms in the nebula, causing them to glow.
IC 418 lies about 2000 light-years away and spans 0.3 light-years across. This false-color image taken from the Hubble Space Telescope reveals the unusual details.
Thursday, 1 May 2025
Moon Shadow
NASA’s Juno spacecraft captured this view of Jupiter during the mission’s 40th close pass by the giant planet on Feb. 25, 2022. The large, dark shadow on the left side of the image was cast by Jupiter’s moon Ganymede.
An observer at Jupiter’s cloud tops within the oval shadow would experience a total eclipse of the Sun. Total eclipses are more common on Jupiter than on Earth for several reasons. Jupiter has four major moons, known as the Galilean satellites, that often pass between Jupiter and the Sun. In seven days, Ganymede transits once, Europa transits twice, and Io four times. Since Jupiter’s moons orbit in a plane close to Jupiter’s orbital plane, moon shadows are often cast upon the planet.
