Planetary Picture of the Day
Week of March 3, 2025
This week, things that look like other things -- a string of pearls, fingers, a crystal ball. What do you see in these images? Plus, we share the results of using infrared observations vs visible light.
Monday, 3 March 2025
String of Pearls
This beautiful triad of storms on Jupiter is part of eight known as "the string of pearls." These storms can reach 1/3 to 2/3 the size of the Earth! Kevin M. Gill processed five images taken on 21 February 2021 by NASA's JunoCam onboard the Juno spacecraft to create this composite image of Jupiter's South Temperate Domain.
Note: JunoCam uses a wide-angle lens, which distorts images and makes foreground objects, like the cyclones, appear larger than they are in reality. They are still really, really big!
Tuesday, 4 March 2025
Finger-Like Rocks
NASA’s Curiosity Mars rover spotted these finger-like rocks with its Mast Camera, or Mastcam, on May 15, 2022, the mission's 3,474th Martian day, or sol. These rocks likely formed as groundwater trickled through rock in the ancient past, depositing mineral cements over time. When the rock was exposed to the atmosphere many years later, wind eroded the softer material around the cemented portions. The rocks were found on Mount Sharp, the 5-kilometer-tall mountain that Curiosity has been climbing since 2014.
Wednesday, 5 March 2025
Planetary Nebula in Infrared
NGC 1514, also known as the Crystal Ball Nebula, is a planetary nebula in the constellation of Taurus. In this infrared image from JWST, the two outer dusty rings appear in neutral gray while the interior parts of the nebula are deep red. Because it is infrared light, these colors do not have traditional meanings like they might with visible light, but they are still indicative of the elemental composition and temperature of the material cast off by the central star as it ended its hydrogen fusing stage before transitioning to a white dwarf.
Infrared observations show that a huge region of dust, spanning 8.5 light years, surrounds the planetary nebula, which is located 2,283 light years away from Earth.
Thursday, 6 March 2025
Saturn's Polar Aurora
This composite image of Saturn's northern polar region shows the aurora and underlying atmosphere, captured by NASA's Cassini spacecraft's visual and infrared mapping spectrometer, at two different wavelengths of infrared light.
Energetic particles crashing into the upper atmosphere cause the aurora, shown in blue, to glow brightly at 4 microns (six times the wavelength visible to the human eye). The image shows both a bright ring, as seen from Earth, and an example of bright auroral emission within the polar cap that had been undetected until the advent of Cassini. This aurora, which defies past predictions of what was expected, has been observed to grow even brighter than is shown here. Silhouetted by the glow (cast here to the color red) of the hot interior of Saturn (clearly seen at a wavelength of 5 microns, or seven times the wavelength visible to the human eye) are the clouds and haze that underlie this auroral region.
Friday, 7 March 2025
Infrared vs Visible Light
The face-on spiral galaxy NGC 1566 is shown twice. At left, Webb’s observations combine near- and mid-infrared light. At right, Hubble’s observations feature visible and ultraviolet light. Dust absorbs ultraviolet and visible light and then re-emits it in the infrared. In Webb's images, we see dust glowing in infrared light. In Hubble’s images, dark regions are where starlight is absorbed by dust. These two instruments make what’s invisible to our senses visible.
