Astronomers discover twelve more Jupiter moons
In reviewing ground-based data from 2021 and 2022, astronomers have discovered another twelve Jupiter moons, bringing that planet’s total moon population to 92.
All of the newly discovered moons are small and far out, taking more than 340 days to orbit Jupiter. Nine of the 12 are among the 71 outermost Jovian moons, whose orbits are more than 550 days. Jupiter probably captured these moons, as evidenced by their retrograde orbits, opposite in direction to the inner moons. Only five of all the retrograde moons are larger than 8 kilometers (5 miles); Sheppard says the smaller moons probably formed when collisions fragmented larger objects.
One newly discovered moon, dubbed Valetudo, is about 3,000 feet across and orbits in a retrograde orbit that crosses the orbits of several other moons that orbit in the opposite direction. As the article notes, “This highly unstable situation is likely to lead to head-on collisions that would shatter one or both objects.”
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
In reviewing ground-based data from 2021 and 2022, astronomers have discovered another twelve Jupiter moons, bringing that planet’s total moon population to 92.
All of the newly discovered moons are small and far out, taking more than 340 days to orbit Jupiter. Nine of the 12 are among the 71 outermost Jovian moons, whose orbits are more than 550 days. Jupiter probably captured these moons, as evidenced by their retrograde orbits, opposite in direction to the inner moons. Only five of all the retrograde moons are larger than 8 kilometers (5 miles); Sheppard says the smaller moons probably formed when collisions fragmented larger objects.
One newly discovered moon, dubbed Valetudo, is about 3,000 feet across and orbits in a retrograde orbit that crosses the orbits of several other moons that orbit in the opposite direction. As the article notes, “This highly unstable situation is likely to lead to head-on collisions that would shatter one or both objects.”
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Either that or a near-miss will eject it from the system.
Just imagine the exploration of the Jupiter system that would be possible with a nuclear-powered Starship. It could be based in orbit around Mars, and make years-long surveying trips into the realm of Jupiter’s moons.
I suspect with nuclear power, the amount of (mono)propellant that would suffice would mean that much of the volume of a Starship could be devoted to living space and supplies to make multi-year voyages feasible, like the sailing ships of old!
I shall call them the ‘dirty dozen’.
Valetudo must be a recent capture; I find hard to believe that something almost a kilometer wide could have been missed by Galileo and others.
David Ross: You clearly don’t understand the sheer scale of space. It’s actually quite impressive that we can identify an object that small at that distance with our current best telescopes. Even with our current optics, nobody has actually “seen” these moons, they are simply too dark and too small to be identified by the human eye. They are detected by having a computer compare literally thousands of separate images taken at different times by different instruments. Even the Hubble only has a resolution of 0.014 arc seconds, which means that at the distance of the Moon, Hubble can resolve to about 27 meters. I don’t have my math text handy to remind me how to calculate an arc second at the distance of Jupiter, but it’s FAR above 1 kilometer. Galileo’s little 20x telescope couldn’t even dream of showing something that small.
“Hubble only has a resolution of 0.014 arc seconds”
WFC3, the current primary visible-light camera, has a pixel scale of about 0.04 arcsec. The corresponding length at Jupiter is about 150 km.