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Plasma Sheet from the Sun

The image below refers to an astrophysical event, occurred last July.

In fact:

A sheet of plasma blasted out into space from just behind the edge of the sun, July 28, 2017. While some material escaped into space, a portion of it was unable to break the pull of gravity and the magnetic forces nearby and can be seen falling back to the sun. The 3.5 hours of action was captured in a wavelength of extreme ultraviolet light.

Sheets of plasma are very interesting to study. In fact, scientists say giant sheets of plasma bursting into pieces may help produce high-energy magnetic reconnections ( that set off the enormous explosions that create solar flares and other powerful astrophysical events.
Actually, a new theory may explain how stars release powerful, unstable bursts of energy. Furthermore, this new theory may also aid our understanding of the solar corona and the solar wind. It may also help us understand the formation of solar jets called spicules, which are abundant in the lower reaches of the sun’s atmosphere.

The research was published by a team led by physicist Luca Comisso from Princeton University, Princeton, New Jersey:

"Plasmoid Instability in Forming Current Sheets", 2017 November 28 in The Astrophysical Journal>>

"General theory of the plasmoid instability", October 2016 in Physics of Plasmas>>

► Image source>>

Image Credit: NASA/GSFC/Solar Dynamics Observatory

#SolarSystem, #PlasmaSheet, #Research, #PlasmaInstabilities, #SunActivity, #MagneticReconnection
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Soaring Over Jupiter

Launched from Earth in 2011, the Juno spacecraft arrived at Jupiter in 2016 to study the giant planet from an elliptical, polar orbit.

Juno's primary goal: understanding origin and evolution of Jupiter, looking for solid planetary core, mapping magnetic field, measuring water and ammonia in deep atmosphere, observing auroras to improve our understanding of Jupiter's formation and evolution.

The spacecraft spent more than a year investigating the planet's origins, interior structure, deep atmosphere and magnetosphere. Juno's study of Jupiter is helping us to understand the history of our own solar system and is providing new insight into how planetary systems form and develop in our galaxy and beyond.

This striking image of Jupiter was taken on Sept. 1, 2017 as Juno performed its eighth flyby. The spacecraft was 7,576 kilometers (4,707 miles) from the tops of the clouds of the planet at a latitude of about -17.4 degrees.

Citizen scientist Gerald Eichstädt processed this image using data from the JunoCam imager. Points of interest are “Whale's Tail” and "Dan's Spot.”

Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt

► Source>>

Further reading and references

► Juno>>

► Juno Mission Website>>

► Whale's Tail>>

► Dan's Spot>>

#Juno, #Jupiter, #Planets #SolarSystem
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Dark Sun Sizzling

This is our Sun. It's the truth, even if it could seem it isn't so.
In fact, even on a normal day, our Sun is sizzling ball of seething hot gas. Unpredictably, regions of strong and tangled magnetic fields arise, causing sunspots and bright active regions. The Sun's surface bubbles as hot hydrogen gas streams along looping magnetic fields. These active regions channel gas along magnetic loops, usually falling back but sometimes escaping into the solar corona or out into space as the solar wind.

Pictured below is our Sun in three colors of ultraviolet light. Since only active regions emit significant amounts of energetic ultraviolet light, most of the Sun appears dark. The colorful portions glow spectacularly, pinpointing the Sun's hottest and most violent regions. Although the Sun is constantly changing, the rate of visible light it emits has been relatively stable over the past five billion years, allowing life to emerge on Earth.

Credit: TRACE Project, Stanford-Lockheed Institute for Space Research, NASA

► Source>>

Further reading

► Sunspot>>

► Solar Corona>>

► Solar wind>>

► Ultraviolet light>>

► Magnetic Fields -- History>>

► Solar constant>>

► A Brief History of Life>>

#SolarSystem, #Sun, #Suspots, #SolarRegions
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Dreaming in Color: Jupiter Fractal Art

When Science meets Art...or Art meets Science, awesome things can happen!

Et voilà a Jovian work of art, where you can see Jupiter’s Great Red Spot as you’ve never seen it before!

Artist Mik Petter created this unique digital piece using data from the JunoCam. The art form, known as fractals, uses mathematical formulas to create an infinite variety of form, detail, color and light.

The tumultuous atmospheric zones in and around the Great Red Spot are highlighted by the author's use of colorful fractals.

Vibrant colors of various tints and hues, combined with the almost organic-seeming shapes, make this image seem to be a colorized and crowded petri dish of microorganisms, or a close-up view of microscopic and wildly-painted seashells.

The original JunoCam image was taken on July 10, 2017.

Let's remind that NASA's Juno mission has been exploring Jupiter since July 2016 with a special passenger on board: JunoCam, an instrument designed to take spectacular close-up color images of the largest planet in our solar system. From the raw images, citizen scientists have processed a range of beautiful photographs that highlight Jupiter’s features, even turning them into works of art.

► Take a look at the original JunoCam image>>

Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Mik Petter

► For more information about Juno go to>>


Further reading and references

► PIA21777: Jupiter Fractal Art >>

► Jupiter’s Great Red Spot: A Swirling Mystery>>

#JetPropulsionLaboratory, #Juno, #Jupiter, #Planets, #SolarSystem
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Asteroid 19482 Harperlee is approaching to Earth

On November 10, the main belt asteroid 19482 Harperlee makes its closest approach to Earth during the asteroid’s orbit around the Sun. The main belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter.

19482 Harperlee was named for Harper Lee (1926-2016), an American novelist widely known for her 1960 novel To Kill a Mockingbird. The novel was inspired by the racist attitudes she observed as a child in a town in Alabama.
The asteroid was discovered at La Silla on 1998-04-25 by Belgian astronomer Eric Walter Elst.

Alternative designations are: 1998 HL102, 1981 GQ1

► Image source>>

More information at:

► IAU, Minor Planet Center>>

► JPL Small-Body Database>>;sstr=19482

#MainBeltAsteroid, #SolarSystem, #Asteroid19482Harperlee
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Return of the Comet 96P/Machholz

Comet 96P, also known as comet Machholz, for amateur astronomer Donald Machholz’s 1986 discovery of the comet, is a short-period sungrazing comet.

It completes an orbit around the Sun every 5.24 years and makes its closest approach to the Sun at a toasty 11 million miles, a very close distance for a comet.

The ESA (European Space Agency) and NASA mission SOHO — short for Solar and Heliospheric Observatory — got a visit from comet 96P these days when it entered its field of view on Oct. 25, 2017. The comet entered the lower right corner of SOHO’s view, and skirted up and around the right edge before leaving on Oct. 30. SOHO also spotted comet 96P in 1996, 2002, 2007 and 2012, making it the spacecraft’s most frequent cometary visitor.

96P/Machholz has an estimated diameter of around 6.4 km (4.0 mi).

It is unusual among comets in several respects. Its highly eccentric 5.2 year orbit has the smallest perihelion distance known among numbered/regular short-period comets, bringing it considerably closer to the Sun than the orbit of Mercury. It is also the only known short-period comet with both high orbital inclination and high eccentricity.
In 2007, 96P/Machholz was found to be both carbon-depleted and cyanogen-depleted, a chemical composition nearly unique among comets with known compositions. The chemical composition implies a different and possible extrasolar origin.

Actually, there are currently three hypotheses to explain the chemical composition of 96P/Machholz.

Extrasolar origin
One hypothesis for the difference is that 96P/Machholz was an interstellar comet from outside the Solar System and was captured by the Sun.

Oort cloud origin
Other possibilities are that it formed in an extremely cold region of the Solar System (such that most carbon gets trapped in other molecules).

Extreme thermal alteration
Given how close it approaches the Sun at perihelion, repeated baking by the Sun has stripped most of its cyanogen.

► Go to a recent article by Lina Tran
NASA’s Goddard Space Flight Center, Greenbelt, Md.>>

► Image: The comet entered the lower right corner of SOHO’s view, and skirted up and around the right edge before leaving on Oct. 30. Jupiter can be seen passing left-to-right behind the solid central disk — called an occulting disk — that blocks sunlight and allows SOHO to see the solar atmosphere, planets and comets.
Credits: ESA/NASA’s Goddard Space Flight Center/SOHO/NRL/Karl Battams/Joy Ng

Further reading and references

► 96P/Machholz>>

► Short-period comet>>

► Sungrazing comet>>

► Interstellar comet>>

► Cyanogen>>

► Perihelion and aphelion>>

► The Extremely Anomalous Molecular Abundances of Comet 96P/MACHHOLZ 1 from Narrowband Photometry>>;jsessionid=A8EFB30E3E1F7784AF4C3AE28986462E.ip-10-40-2-120

#Comets, #SOHO, #SolarSystem, #STEREO, #Sun, #Comet96P/Machholz
Animated Photo
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Hubble Focus: Our Amazing Solar System (e-book)

NASA’s Hubble Space Telescope team has unveiled a new e-book titled “Hubble Focus: Our Amazing Solar System.”
It kicks off a series of e-books that will showcase the telescope’s recent contributions to many different fields of astronomy.

The new e-book is compatible with most electronic devices and can be downloaded in multiple formats for free.


► ePub format (108 MB)>>

► PDF format (80 MB)>>

Read more>>

#SolarSystem, #Ebook, #HubbleSpaceTelescope
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C/2017 K2: the Farthest Active Inbound Comet Yet Seen

NASA's Hubble Space Telescope observed the farthest-discovered active inbound comet, called C/2017 K2 (PANSTARRS) or "K2".
K2 came from the distant Oort Cloud and is visiting our inner solar system for the first (and only) time. Since we're seeing it so far away, past the orbit of Saturn, K2 is still in its early phase of activity, likely making it the most primitive comet anyone has ever seen.

"K2 is so far from the Sun and so cold, we know for sure that the activity — all the fuzzy stuff making it look like a comet — is not produced, as in other comets, by the evaporation of water ice," said lead researcher David Jewitt of the University of California, Los Angeles. "Instead, we think the activity is due to the sublimation [a solid changing directly into a gas] of super-volatiles as K2 makes its maiden entry into the solar system's planetary zone. That's why it's special. This comet is so far away and so incredibly cold that water ice there is frozen like a rock."

K2 was discovered in May 2017 by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) in Hawaii, a survey project of NASA's Near-Earth Object Observations Program. Jewitt used Hubble's Wide Field Camera 3 at the end of June to take a closer look at the icy visitor.

For the next five years, the comet will continue its journey into the inner solar system before it reaches its closest approach to the Sun in 2022 just beyond Mars' orbit.

A curiosity: the Hubble images do not show a tail flowing from K2, which is a signature of comets. The absence of such a feature indicates that particles lifting off the comet are too large for radiation pressure from the Sun to sweep them back into a tail.

NASA's James Webb Space Telescope, scheduled to launch in 2019 (the telescope will be launched on an Ariane 5 rocket from French Guiana in Spring 2019), could measure the heat from the nucleus, which would give astronomers a more accurate estimate of its size.

Learn more>>

► Read the science paper "A Comet Active Beyond the Crystallization Zone" here:

Image explanation: This illustration shows the orbit of comet C/2017 K2 PANSTARRS (K2) on its maiden voyage into the solar system. The Hubble Space Telescope observed K2 when it was 1.5 billion miles from the Sun, halfway between the orbits of Saturn and Uranus. The farthest object from the Sun depicted here is the dwarf planet Pluto, which resides in the Kuiper Belt, a vast rim of primordial debris encircling our solar system.
Credits: NASA, ESA, and A. Feild (STScI)

#Comets, #HubbleSpaceTelescope, #SolarSystem, #C/2017_K2
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Saturn's Magnetosphere

The magnetosphere of Saturn is the cavity created in the flow of the solar wind by the planet's internally generated magnetic field. Discovered in 1979 by the Pioneer 11 spacecraft, Saturn's magnetosphere is the second largest of any planet in the Solar System after Jupiter. The magnetopause, the boundary between Saturn's magnetosphere and the solar wind, is located at a distance of about 20 Saturn radii from the planet's center, while its magnetotail stretches hundreds of Saturn radii behind it.

Saturn's magnetosphere is filled with plasmas originating from both the planet and its moons. The main source is the small moon Enceladus, which ejects as much as 1,000 kg/s of water vapor from the geysers on its south pole, a portion of which is ionized and forced to co-rotate with the Saturn’s magnetic field. This loads the field with as much as 100 kg of water group ions per second. This plasma gradually moves out from the inner magnetosphere via the interchange instability mechanism and then escapes through the magnetotail.

The interaction between Saturn's magnetosphere and the solar wind generates bright oval aurorae around the planet's poles observed in visible, infrared and ultraviolet light. The aurorae are related to the powerful saturnian kilometric radiation (SKR).

In 1980–1981 the magnetosphere of Saturn was studied by the Voyager spacecraft. Up until September of 2017 it was a subject of ongoing investigation by Cassini mission, which arrived in 2004 and spent over 13 years observing the planet.

Measurements from Cassini have totally changed our understanding of Saturn’s magnetosphere, yet many questions still remain.

In fact, scientists had little information about Saturn’s magnetosphere because magnetic fields are invisible and are best studied from within. Cassini has studied Saturn's magnetosphere like never before by mapping the magnetic field, studying the flow of excited gases under its influence and observing how it affects Saturn’s auroras. The results have provided powerful insights about how Saturn's inner workings affect the planet's atmosphere and the space around it.

► Image source>>

Further reading and references

► Magnetosphere>>

► Magnetosphere of Saturn>>

► Saturn's magnetosphere>>

#SolarSystem, #Saturn, #Magnetosphere, #CassiniMission, #Space, Astronomy
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Rhea in front of Titan

The image below shows the Saturn’s largest and second largest moons, Titan and Rhea.

Titan is the second largest moon in our solar system, second only to Jupiter's Ganymede, which is only 2 percent larger. With a mean radius of 1,600 miles (2,575 km), Titan is bigger than Earth's moon, and even larger than the planet Mercury.

Titan is the only moon in our solar system that has clouds and a dense atmosphere, mostly nitrogen and methane. It is also the only other place in the solar system known to have an earthlike cycle of liquids flowing across its surface.

Rhea is smaller than Earth’s moon and, with a mean radius of 475 miles (764 km), is less than a third the radius of Titan.
Rhea is a small, cold, airless body that is very similar to sister moons Dione and Tethys. Its density of 1.233 times that of liquid water suggests that Rhea is three quarters ice and one quarter rock.

Titan and Rhea appear to be stacked on top of each other, in this true-color scene from NASA's Cassini spacecraft.

The north polar hood can be seen on Titan appearing as a detached layer at the top of the moon on the top right.

This view looks toward the Saturn-facing side of Rhea (949 miles or 1528 kilometers across). North on Rhea is up and rotated 35 degrees to the right.

Images taken using red, green and blue spectral filters were combined to create this natural-color view. The images were acquired with the Cassini spacecraft narrow-angle camera on June 16, 2011, at a distance of approximately 1.1 million miles (1.8 million kilometers) from Rhea and 1.5 million miles (2.5 million kilometers) from Titan. Image scale is 7 miles (11 kilometers) per pixel on Rhea and 9 miles (15 kilometers) on Titan.

► Image source>>
Image credit: NASA / JPL-Caltech / Space Science Institute.

Further reading and references

► Fire and Ice>>

► Haze Layers on Titan >>

► Titan>>

► Rhea>>

► Imaging Science Subsystem>>

#SolarSystem, #SaturnMoons, #Titan, #Rhea, #CassiniMission
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