Cosmic Space

Jupiter and Saturn pair up to make a Christmas Star

Are you ready for a remake of the Christmas Star story? Depending on how much stock you put in historical hypotheses, this year’s solstice on Dec. 21 could bring a replay of the phenomenon that the Three Kings saw in the Gospel of Matthew.

That’s when Jupiter and Saturn can be seen incredibly close together in the night sky. If the skies are clear, the two planets will be hard to miss in southwest skies just after sunset, as seen from mid-northern latitudes. Jupiter will sparkle brighter, and Saturn will be shining only a tenth of a degree to the upper right. With a small telescope, you might be able to see both planets and their moons in a single field of view.

“Some astronomers suggest the pair will look like an elongated star, and others say the two planets will form a double planet,” NASA says in a blog posting about the Dec. 21 conjunction. “To know for sure, we’ll just have to look and see. Either way, take advantage of this opportunity because Jupiter and Saturn won’t appear this close in the sky until 2080!”


Suggest names for Saturn’s latest crop of moons

This artist’s conception shows the 20 newly discovered moons orbiting Saturn. (Illustration courtesy of Carnegie Institute for Science. Saturn image courtesy of NASA / JPL-Caltech / Space Science Institute. Starry background courtesy of Paolo Sartorio / Shutterstock.)

Saturn has pulled ahead of Jupiter again in the moon discovery race, thanks to a batch of 20 outer moons that bring the ringed planet’s total tally to 82.

The newly reported satellites, confirmed by the International Astronomical Union’s Minor Planet Center, were found by the same team that reported spotting 12 new moons of Jupiter last year.

As was the case with those moons of Jupiter, the discovery team at the Carnegie Institution for Science is soliciting suggestions for naming the newly reported moons of Jupiter. Right now, they’re known only by their numerical designations, such as S/2004 S29 or S5593a2.

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Saturn orbiter fights for science to the end

JPL Mission Control
Cassini project manager Earl Maize hugs Julie Webster, spacecraft operations team manager, at Mission Control at NASA’s Jet Propulsion Laboratory just after the mission’s end. Program scientist Linda Spilker is at left, and Jim Green, the head of NASA’s Planetary Science Division, is at right. (NASA Photo / Joel Kowsky)

Before its destruction, the bus-sized Cassini spacecraft fought Saturn’s buffeting atmosphere to send back scientific data for even longer than NASA thought it would.

But the end was inevitable: Twenty years after its launch, and 13 years after its arrival at the ringed planet, the final signals from Cassini were received at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., at 4:55:46 a.m. PT today.

“I’m going to call this the end of mission,” Cassini project manager Earl Maize declared, during an early-morning webcast that was watched by tens of thousands. “Project manager, off the net.”

The end was pre-ordained days earlier, when a final maneuver put the spacecraft on a course to dive into Saturn’s upper atmosphere. NASA meticulously planned out the controlled descent to make sure there was no chance that Cassini could crash into one of Saturn’s moons, which are certain to be targets for future missions.

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Cassini takes its parting shots at Saturn

Saturn view
Saturn and its rings star in one of the last raw images sent back by the Cassini orbiter. (NASA / JPL-Caltech / Space Science Institute)

The final pictures from NASA’s 13-year-long Cassini mission at Saturn are flowing in – and they’re good to the last drop.

Or even better, good to the last moonset.

Raw images, captured by Cassini’s cameras during the run-up to the bus-sized spacecraft’s scheduled destruction on Sept. 15, have been popping up by the dozens on NASA’s mission website.

Among the still-image sequences are pictures showing Enceladus, an ice-covered moon that could conceivably harbor life, as it sets on the Saturnian horizon.

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Saturn probe will go out in a blaze of science

Cassini orbiter
An artist’s conception shows the Cassini orbiter zooming through the upper layers of Saturn’s atmosphere, heading for a fiery breakup. (NASA / JPL-Caltech Illustration)

Twenty years after its launch to Saturn, NASA has set the Cassini orbiter on a course for certain destruction on Sept. 15 – but there’s a decidedly positive spin to the $3.3 billion mission’s end.

“We’ll be saddened, there’s no doubt about it, at the loss of such an incredible machine,” Cassini program manager Earl Maize said Sept. 13 during a news briefing at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “But I think all of us are going to have a great sense of pride in .. a little bit corny, perhaps … a ‘mission accomplished.’”

The bus-sized, plutonium-powered spacecraft was launched in 1997 and reached Saturn seven years later. It’s logged 4.9 billion miles, sent back nearly half a million images of the ringed planet and its moons, and transmitted 635 gigabytes worth of scientific data so far.

It’ll continue sending data all the way to the end, when it’s expected to break apart and burn up in the upper levels of Saturn’s atmosphere.

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Listen to the sound of silence in Saturn orbit

Saturn and rings
The hexagon-shaped cloud system at Saturn’s north polar region looms in the foreground with the planet’s rings stretching across the background, in an image captured by the Cassini spacecraft’s camera on April 26. Click on the image for a larger version. (NASA / JPL-Caltech / Kevin M. Gill Image / CC-BY-2.0)

The researchers behind NASA’s Cassini mission to Saturn are relieved, and a bit mystified, to discover that the narrow gap between the giant planet and its rings is virtually devoid of stray particles.

The discovery comes from the bus-sized Cassini spacecraft’s first dive through the gap on April 26, which marked the beginning of the end for the 20-year mission.

“The region between the rings and Saturn is ‘The Big Empty,’ apparently,” Cassini project manager Earl Maize of NASA’s Jet Propulsion Laboratory said in a news release.

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Cassini probe survives dive inside Saturn rings

Saturn view from Cassini
This unprocessed image of Saturn’s atmosphere was captured by the Cassini probe during its dive inside the planet’s rings. (NASA / JPL-Caltech / Space Science Institute Image)

NASA’s Cassini orbiter zoomed inside Saturn’s rings overnight for the first time in its 20-year-long flight – and lived to tell about it.

Signals received by the Deep Space Network’s Goldstone radio antenna in California confirmed that the bus-sized spacecraft survived its closest-ever encounter with the ringed planet.

Cassini zoomed as close as 1,900 miles to Saturn’s cloud tops and within about 200 miles of the innermost visible edge of the rings, at a relative speed of 77,000 mph, NASA reported in an update early today.

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UFO? No, it’s Pan, a weird moon of Saturn

A picture taken by the high-resolution camera on the Cassini orbiter shows Pan’s weird-looking equatorial ridge. (NASA / JPL-Caltech / SSI)

Astronomers have long known that Pan, one of the “shepherd moons” in Saturn’s rings, had a weird shape. But it took this week’s high-resolution images from the Cassini orbiter to show them just how weird.

Cassini got its closest look ever at Pan on March 7, when it came within a little more than 15,000 miles of the 20-mile-wide moon. In the close-ups released on March 9, the thing looks like a flattened flying saucer, complete with a bulging ridge around the edge.

Overnight, the views sparked rounds of hilarity and awe on Twitter. Was it a cosmic turtle shell? Walnut? Ravioli? And what’s behind that strange, strange shape?

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