Where’s Juno?

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In case you were wondering where Juno is on the trip to Jupiter, wonder no more.

81 days to go!

From NASA (25 March 2016):

As of March 25, 2016, Juno is approximately 410 million miles (659 million kilometers) from Earth. The one-way radio signal travel time between Earth and Juno is currently about 37 minutes.

Juno is traveling at a velocity of approximately 53,000 miles per hour (about 23.6 kilometers per second) relative to Earth, 16,000 miles per hour (about 7.1 kilometers per second) relative to the Sun, and 13,000 miles per hour (about 5.7 kilometers per second) relative to Jupiter. Juno has now travelled 1.73 billion miles (2.78 billion kilometers, or 18.56 AU) since launch, and has another 34 million miles to go (55 million kilometers, or 0.37 AU) before entering orbit around Jupiter.

The Juno spacecraft is in excellent health and is operating nominally.

Juno is slated to arrive at the gas giant planet on July 4, 2016, at 8:35 p.m. PDT (Earth Received Time). Track and visualize Juno’s journey through space using NASA’s Eyes on the Solar System 3D interactive.

Juno’s onboard color camera, called JunoCam, invites the public to serve as a virtual imaging team. Vote and comment on where to point JunoCam and which features to image on Jupiter using the new JunoCam web platform at missionjuno.com.

 Image: NASA

Starshot

Russian scientist and billionaire entrepreneur Yuri Milner and Cosmologist and theoretical physicist Stephen Hawking announced a space exploration project called Breakthrough Starshot

Video – short version
Video – long version

Ice Spider on Pluto

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No, not some science fiction movie, but close, Pluto is very strange.

Credit: NASA / John Hopkins APL / SwRI

From New Horizons:

Sprawling across Pluto’s icy landscape is an unusual geological feature that resembles a giant spider.

“Oh, what a tangled web Pluto’s geology weaves,” said Oliver White, a member of the New Horizons geology team from NASA Ames Research Center, Mountain View, California. “The pattern these fractures form are like nothing else we’ve seen in the outer solar system, and shows once again that anywhere we look on Pluto, we see something different.”

As shown in the enhanced color image below – obtained by NASA’s New Horizons spacecraft on July 14, 2015 – this feature consists of at least six extensional fractures (indicated by white arrows in this annotated version) converging to a point near the center. The longest fractures are aligned roughly north-south, and the longest of all, the informally named Sleipnir Fossa, is more than 360 miles (580 kilometers) long.  The fracture aligned east-west is shorter and reaches less than 60 miles (100 kilometers) long.  To the north and west, the fractures extend across the mottled, rolling plains of the high northern latitudes, and to the south, they intercept and cut through the bladed terrain informally named Tartarus Dorsa.

Curiously, the spider’s “legs” noticeably expose red deposits below Pluto’s surface.

New Horizons scientists think fractures seen elsewhere on Pluto, which tend to be aligned parallel to each other in long belts – rather than intersecting with one another at a nexus, as this feature does – are caused by global-scale extension of Pluto’s water–ice crust.  However, given the curious radiating pattern of the fractures forming the “spider,” it may instead be caused by a focused source of stress in the crust under the point where the fractures converge – for example, due to material welling up from under the surface.  The spider somewhat resembles “radially fractured centers” on Venus called novae (http://photojournal.jpl.nasa.gov/catalog/PIA00150) seen by NASA’s Magellan spacecraft, as well as the Pantheon Fossae formation seen by NASA’s MESSENGER spacecraft on Mercury (http://photojournal.jpl.nasa.gov/catalog/PIA19410).

This image was obtained by New Horizons’ Ralph/Multispectral Visible Imaging Camera (MVIC).  The image resolution is approximately 2,230 feet (680 meters) per pixel.  It was obtained at a range of approximately 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before New Horizons’ closest approach on July 14, 2015.

The Cassini Division

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The Cassini site has a labeled picture here you might find helpful.

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Keep an eye out for local Yuri’s Night Celebrations, you probably have one near you (no matter where you are and it’s a good bet a scope will be on Jupiter and/or Saturn.  Both are so worth the look if you’ve never seen them for yourself, especially Saturn – it is dazzling!

From the Cassini site:

It’s difficult to get a sense of scale when viewing Saturn’s rings, but the Cassini Division (seen here between the bright B ring and dimmer A ring) is almost as wide as the planet Mercury. (See PIA11142 for a labeled panorama of features in the rings.)

The 2,980-mile-wide (4,800-kilometer-wide) division in Saturn’s rings is thought to be caused by the moon Mimas. Particles within the division orbit Saturn almost exactly twice for every time that Mimas orbits, leading to a build-up of gravitational nudges from the moon. These repeated gravitational interactions sculpt the outer edge of the B ring and keep its particles from drifting into the Cassini Division.

This view looks toward the sunlit side of the rings from about 4 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 28, 2016.

The view was acquired at a distance of approximately 740,000 miles (1.2 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 76 degrees. Image scale is 4 miles (7 kilometers) per pixel.

Cassini and Planet 9

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LOL. I’ve been getting quite a kick out of some of the hoopla surrounding “Planet 9” and saw the stories about how Cassini’s orbit was getting knocked about by the gravity of said planet.

I’ve even seen claims that NASA  is projecting a huge hologram into the sky in order to hide the sight of “Planet 9” coming right at us, after all according to these people,  it is supposed to be on a track to hit is in April and by my reckoning there is less than three-weeks left.

One tiny problem, we don’t even know for sure if “Planet 9” even exists, to say nothing about the rest of it. Although I would love to believe NASA could produce a big hologram like that, but no sadly they can’t.  Oh well, it makes for some good science fiction.

Anyway to address the Cassini’s orbital perturbations,  the Cassini team has this to say:

Saturn Spacecraft Not Affected by Hypothetical Planet 9

Contrary to recent reports, NASA’s Cassini spacecraft is not experiencing unexplained deviations in its orbit around Saturn, according to mission managers and orbit determination experts at NASA’s Jet Propulsion Laboratory in Pasadena, California.

Several recent news stories have reported that a mysterious anomaly in Cassini’s orbit could potentially be explained by the gravitational tug of a theorized massive new planet in our solar system, lurking far beyond the orbit of Neptune. While the proposed planet’s existence may eventually be confirmed by other means, mission navigators have observed no unexplained deviations in the spacecraft’s orbit since its arrival there in 2004.

“An undiscovered planet outside the orbit of Neptune, 10 times the mass of Earth, would affect the orbit of Saturn, not Cassini,” said William Folkner, a planetary scientist at JPL. Folkner develops planetary orbit information used for NASA’s high-precision spacecraft navigation. “This could produce a signature in the measurements of Cassini while in orbit about Saturn if the planet was close enough to the sun. But we do not see any unexplained signature above the level of the measurement noise in Cassini data taken from 2004 to 2016.”

A recent paper predicts that, if data tracking Cassini’s position were available out to the year 2020, they might be used to reveal a “most probable” location for the new planet in its long orbit around the sun. However, Cassini’s mission is planned to end in late 2017, when the spacecraft — too low on fuel to continue on a longer mission — will plunge into Saturn’s atmosphere.

“Although we’d love it if Cassini could help detect a new planet in the solar system, we do not see any perturbations in our orbit that we cannot explain with our current models,” said Earl Maize, Cassini project manager at JPL.

Image and press release: The Cassini-Huygens mission is a cooperative project of NASA, ESA and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington.