Jupiter’s Racing Stripes By NASA’s Marshall Space Flight Center

Image of the moon of Saturn, Enceladus, taken by the Cassini spacecraft

Image credit: NASA / JPL

Ocean on the moon Europa

Scientists' consensus is that a layer of liquid water exists beneath Europa's surface, and that heat from tidal flexing allows the subsurface ocean to remain liquid.

Europa's surface temperature averages about 110 K (−160 °C; −260 °F) at the equator and only 50 K (−220 °C; −370 °F) at the poles, keeping Europa's icy crust as hard as granite. The first hints of a subsurface ocean came from theoretical considerations of tidal heating (a consequence of Europa's slightly eccentric orbit and orbital resonance with the other Galilean moons). Galileo imaging team members argue for the existence of a subsurface ocean from analysis of Voyager and Galileo images.

The most dramatic example is "chaos terrain", a common feature on Europa's surface that some interpret as a region where the subsurface ocean has melted through the icy crust.

The thin-ice model suggests that Europa's ice shell may be only a few kilometers thick. However, most planetary scientists conclude that this model considers only those topmost layers of Europa's crust that behave elastically when affected by Jupiter's tides.

The Hubble Space Telescope acquired an image of Europa in 2012 that was interpreted to be a plume of water vapour erupting from near its south pole The image suggests the plume may be 200 km (120 mi) high, or more than 20 times the height of Mt. Everest.

Life?

So far, there is no evidence that life exists on Europa, but Europa has emerged as one of the most likely locations in the Solar System for potential habitability. Life could exist in its under-ice ocean, perhaps in an environment similar to Earth's deep-ocean hydrothermal vents. Even if Europa lacks volcanic hydrothermal activity, a 2016 NASA study found that Earth-like levels of hydrogen and oxygen could be produced through processes related to serpentinization and ice-derived oxidants, which do not directly involve volcanism.

In 2015, scientists announced that salt from a subsurface ocean may likely be coating some geological features on Europa, suggesting that the ocean is interacting with the seafloor. This may be important in determining if Europa could be habitable. The likely presence of liquid water in contact with Europa's rocky mantle has spurred calls to send a probe there.

Missions

Europa Clipper is an interplanetary mission in development by NASA comprising an orbiter. Set for a launch in October 2024, the spacecraft is being developed to study the Galilean moon Europa through a series of flybys while in orbit around Jupiter.

The Europa Lander is a proposed astrobiology mission concept by NASA to Europa, an icy moon of Jupiter. If funded and developed as a large strategic science mission, it would be launched in 2027 to complement the studies by the Europa Clipper orbiter mission and perform analyses on site. NASA's budget for fiscal year 2021 neither mandates nor allocates any funds to the mission leaving its future uncertain.

The objectives of the mission are to search for biosignatures at the subsurface ≈10 cm, to characterize the composition of non-ice near-subsurface material, and determine the proximity of liquid water and recently erupted material near the lander's location.

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Sampling the ocean on Enceladus by europeanspaceagency

Perseverance: Some early Navcam (navigation camera) images taken over the (Earth) weekend on sol 2. Originals are here: [1] [2] [3] [4]. Credit: NASA/JPL-Caltech

The Pale Blue Dot

The “Pale Blue Dot” is a photograph of planet Earth taken in 1990 by Voyager 1 from a record distance, showing it against the vastness of space.

By request of Carl Sagan, NASA commanded the Voyager 1 spacecraft, having completed its primary mission and now leaving the Solar System, to turn its camera around and to take a photograph of Earth across a great expanse of space. Reflecting on this picture (now considered one of the most important pictures in all of human history) Carl Sagan said:

“From this distant vantage point, the Earth might not seem of particular interest. But for us, it’s different. Consider again that dot. That’s here, that’s home, that’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.”

July 20, 1969

Project Apollo on Flickr

Storm Clouds of Jupiter

Solar System 10 Things: Looking Back at Pluto

In July 2015, we saw Pluto up close for the first time and—after three years of intense study—the surprises keep coming. “It’s clear,” says Jeffery Moore, New Horizons’ geology team lead, “Pluto is one of the most amazing and complex objects in our solar system.”

1. An Improving View

These are combined observations of Pluto over the course of several decades. The first frame is a digital zoom-in on Pluto as it appeared upon its discovery by Clyde Tombaugh in 1930. More frames show of Pluto as seen by the Hubble Space Telescope. The final sequence zooms in to a close-up frame of Pluto taken by our New Horizons spacecraft on July 14, 2015.

2. The Heart

Pluto’s surface sports a remarkable range of subtle colors are enhanced in this view to a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a complex geological and climatological story that scientists have only just begun to decode. The image resolves details and colors on scales as small as 0.8 miles (1.3 kilometers). Zoom in on the full resolution image on a larger screen to fully appreciate the complexity of Pluto’s surface features.

3. The Smiles

July 14, 2015: New Horizons team members Cristina Dalle Ore, Alissa Earle and Rick Binzel react to seeing the spacecraft’s last and sharpest image of Pluto before closest approach.

4. Majestic Mountains

Just 15 minutes after its closest approach to Pluto, the New Horizons spacecraft captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto’s horizon. The backlighting highlights more than a dozen layers of haze in Pluto’s tenuous atmosphere. The image was taken from a distance of 11,000 miles (18,000 kilometers) to Pluto; the scene is 780 miles (1,250 kilometers) wide.

5. Icy Dunes

Found near the mountains that encircle Pluto’s Sputnik Planitia plain, newly discovered ridges appear to have formed out of particles of methane ice as small as grains of sand, arranged into dunes by wind from the nearby mountains.

6. Glacial Plains

The vast nitrogen ice plains of Pluto’s Sputnik Planitia – the western half of Pluto’s “heart”—continue to give up secrets. Scientists processed images of Sputnik Planitia to bring out intricate, never-before-seen patterns in the surface textures of these glacial plains.

7. Colorful and Violent Charon

High resolution images of Pluto’s largest moon, Charon, show a surprisingly complex and violent history. Scientists expected Charon to be a monotonous, crater-battered world; instead, they found a landscape covered with mountains, canyons, landslides, surface-color variations and more.

8. Ice Volcanoes

One of two potential cryovolcanoes spotted on the surface of Pluto by the New Horizons spacecraft. This feature, known as Wright Mons, was informally named by the New Horizons team in honor of the Wright brothers. At about 90 miles (150 kilometers) across and 2.5 miles (4 kilometers) high, this feature is enormous. If it is in fact an ice volcano, as suspected, it would be the largest such feature discovered in the outer solar system.

9. Blue Rays

Pluto’s receding crescent as seen by New Horizons at a distance of 120,000 miles (200,000 kilometers). Scientists believe the spectacular blue haze is a photochemical smog resulting from the action of sunlight on methane and other molecules in Pluto’s atmosphere. These hydrocarbons accumulate into small haze particles, which scatter blue sunlight—the same process that can make haze appear bluish on Earth.

10. Encore

On Jan. 1, 2019, New Horizons will fly past a small Kuiper Belt Object named MU69 (nicknamed Ultima Thule)—a billion miles (1.5 billion kilometers) beyond Pluto and more than four billion miles (6.5 billion kilometers) from Earth. It will be the most distant encounter of an object in history—so far—and the second time New Horizons has revealed never-before-seen landscapes.

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Launching of the space shuttle Atlantis.

Amazing Space Shuttle Shot. 🚀