Cassini made it! On April 26, 2017, NASA’s Saturn-exploring spacecraft made its closest pass by the planet since its arrival in 2004, beginning the final phase of its mission with its first “Grand Finale” orbital pass that took it between the top of the planet’s atmosphere and the innermost edge of the ring system. It’s literally a journey that no other spacecraft has ever made—and now the pictures are coming in!
It’s also the closest Cassini has come to Saturn itself; at closest point Cassini was only about 1,900 miles (3,000 km) above the tops of Saturn’s swirling clouds. It’s amazing to think that the images we’re seeing were captured with Cassini’s wide angle camera—typically views like this have had to use its “zoom” narrow-angle camera!
Check out an animation below of some of Cassini’s views captured during the pass over Saturn’s north pole.
Those white areas aren’t clouds; they’re aurorae—”northern lights”—around the poles of Uranus, captured by the Hubble Space Telescope in 2012 and 2014. (The image of Uranus itself was acquired by the Voyager 2 spacecraft in January 1986.)
“The auroras on Jupiter and Saturn are well-studied, but not much is known about the auroras of the giant ice planet Uranus. In 2011, the NASA/ESA Hubble Space Telescope became the first Earth-based telescope to snap an image of the auroras on Uranus. In 2012 and 2014 a team led by an astronomer from Paris Observatory took a second look at the auroras using the ultraviolet capabilities of the Space Telescope Imaging Spectrograph (STIS) installed on Hubble.”
Aurorae on Uranus are driven by the same process that creates them around Earth’s polar regions: charged particles from the Sun get caught in the planet’s magnetic field and are focused toward the poles, where they make ions in the upper atmosphere release energy—in these observations in ultraviolet wavelengths. Also, since Uranus orbits the Sun “tilted sideways” its polar regions are near the plane of its orbit.
Read the rest of this article from NASA here: Hubble Spots Auroras on Uranus
Mars isn’t a planet well-known for its natural satellites but it actually does have two small moons. The larger, Phobos, is an irregularly-shaped, heavily grooved and cratered world only about 17 miles (27 km) across at its widest. It orbits Mars so closely that it completes 3 orbits every day, and isn’t even visible from some parts of the planet. But Phobos has an even smaller companion in orbit: Deimos, which at the most 7.5 miles across is half Phobos’ size. Deimos orbits Mars much further away as well, taking about 30 hours to complete one orbit.
This is a blog post I wrote in March of 2008—a year before there was even Lights in the Dark! I’m sharing it again because it’s fun…I hope you think so too.
We’ve all seen the grade-school models of the solar system. Maybe you made one in science class. Out of painted styrofoam balls or colored construction paper. Maybe you saw one of those giant models hanging from the ceiling of your local science museum. Big colorful globes, some with rings around them, some painted swirly colors, others looking more like pitted rocks. For most people, that’s their impression of the solar system. Yellow sun in the middle, then all the different colored balls swooping around it. Some people even remember all the names from third-grade science class. Maybe even in order. (My Very Eager Mother Just Served Us Nine Pies?) If so, scratch-n-sniff stickers all around. Yum, root beer!
In what’s being called a “record-breaking exoplanet discovery” NASA announced today the detection of not one, not two, not three or four but seven exoplanets orbiting the ultra-cool dwarf star TRAPPIST-1, located just under 40 light-years away in the constellation Aquarius. (That’s astronomically very close, although still 235 trillion miles distant.) What’s more, these exoplanets aren’t bloated hot Jupiters or frigid Neptune-like worlds but rather dense, rocky planets similar in size to Earth…and at least three of them are well-positioned around their dim red star to permit liquid water to exist on their surfaces.
TRAPPIST-1 and its planets are like a miniature version of our inner Solar System; the star itself is only slightly larger than Jupiter with a mass about 8% of our Sun, and the planets B through H all have orbits smaller than the diameter of Mercury’s. Still, even an ultra-cool dwarf star has a habitable zone, and three of these planets lie within it. The others may very well also possess habitable regions on or inside them too.
“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington, D.C. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”
The seven-planet system was confirmed through (and named for) the ground-based TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) telescope as well as observations from NASA’s Spitzer Space Telescope.
“This is the most exciting result I have seen in the 14 years of Spitzer operations,” said Sean Carey, manager of NASA’s Spitzer Science Center at Caltech/IPAC in Pasadena. “Spitzer will follow up in the fall to further refine our understanding of these planets so that the James Webb Space Telescope can follow up. More observations of the system are sure to reveal more secrets.”