Category Archives: Jupiter
We are the stewards of over 400 years of scientific exploration of our Solar System, which it could be said began in earnest when Galileo Galilei first observed the motions of Jupiter’s moons in his homemade telescope in 1610. Over the centuries our knowledge—and our curiosity—about the seemingly endless variety of worlds in the Solar System has grown in leaps and bounds since Galileo’s first peeks at Jupiter, with increasingly more powerful telescopes both on Earth and in space and eventually even machines sent to join the planets in orbit around the Sun.
Last night NASA’s Juno spacecraft became humanity’s most recent emissary to the Solar System’s biggest planet, successfully performing the rocket burns needed to enter orbit around Jupiter—the first spacecraft to do so in 13 years. Amongst much excitement and deserved congratulations of the mission team, the video above was released showing Juno’s view as it approached the enormous planet the week before arrival after five years and 1.7 billion miles of travel. It’s dramatic and impressive and beautiful…just as it should be, considering the scope and achievement of the mission and the information that will soon be returned. Congratulations Juno!
“With Juno, we will investigate the unknowns of Jupiter’s massive radiation belts to delve deep into not only the planet’s interior, but into how Jupiter was born and how our entire solar system evolved.”
— NASA Administrator Charles Bolden
(HT to Rachelle Williams @AstroAnarchy for the video tip.)
After nearly 5 years of traveling through space NASA’s Juno spacecraft is just a few dozen hours away from entering orbit around Jupiter, the Solar System’s largest, most massive, and most extreme planet.
“We are ready,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute (SwRI). “The science team is incredibly excited to be arriving at Jupiter. The engineers and mission controllers are performing at an Olympic level getting Juno successfully into orbit. As Juno barrels down on Jupiter, the scientists are busy looking at the amazing approach science the spacecraft has already returned to Earth. Jupiter is spectacular from afar and will be absolutely breathtaking from close up.”
Learn more about the mission and find out how to watch the long-awaited event live below:
Captured by NASA’s Galileo spacecraft on April 5, 1997, this image shows Enki Catena, a 161.3-km (100-mile) long crater chain on the surface of Jupiter’s moon Ganymede. Named after the Sumerian god of fresh water, Enki Catena is thought to have been formed when a comet approached too close to Jupiter and was torn into 13 pieces, each impacting Ganymede in rapid succession… sort of a miniature version of what occurred in 1994 with comet Shoemaker-Levy 9.
Ganymede is not only Jupiter’s largest moon but also the largest moon in the Solar System. At 5,268 km (3,273 miles) across it is larger than Pluto and Mercury, and is the only moon that generates its own magnetosphere.
Launched in October 1989, Galileo arrived at Jupiter in December 1995 and orbited the giant planet 34 times before ending its mission with a dive into Jupiter’s atmosphere on September 21, 2003. Learn more about Galileo mission highlights here.
Note: This is an edited repost of an article from 2014.
405 years ago tonight, January 7, 1610, the Pisan astronomer Galileo Galilei looked up at a bright Jupiter at opposition through his handmade telescope and saw three little “stars” next to it, which piqued his natural scientific curiosity. He soon realized that these little objects weren’t stars at all but rather moons orbiting the giant planet (and, most importantly, not Earth). Further observations over the next few nights showed that the planet wasn’t moving relative to the little “stars” as it should if they were indeed background stars, and in fact the smaller bodies (of which he soon saw four) were moving along with Jupiter each in its own little orbit. This revelation helped change our entire view of the Solar System, causing no end of trouble for Galileo (as the Church didn’t appreciate data contradicting their conveniently Earth-centered Universe) but also opening the door for the discovery of many more moons around other planets.
Today Jupiter is now known to have at least 50 moons, with possibly as many as 67!
We have all marveled at incredible photos and time-lapse videos of Earth’s auroral displays, captured by talented photographers that have braved the frigid nighttime temperatures of remote high-latitude locations as well as by those privileged few living in orbit aboard the International Space Station. But our planet isn’t the only one with curtains of light crowning its poles – aurorae have been observed on Jupiter, Saturn, Uranus, and Neptune as well (and Venus may even have them too.) While we know that these light shows are caused by interactions between atoms in planets’ upper atmospheres and charged particles from the Sun that get caught up in magnetic fields focusing out from around the poles, Jupiter in particular is known to have a peculiar additional type of auroral feature, created by the moons that orbit it.
The image above, captured by the Hubble Space Telescope Imaging Spectrograph (STIS) on November 26, 1998, shows Jupiter’s north polar region in ultraviolet light. The planet’s energetic aurorae can be seen wrapping around its pole in wavy circular arcs, just like Earth’s does. But there are also several bright spots that aren’t due to solar activity but are instead the “footprints” of three of its largest moons: Ganymede, Europa, and Io.