Neptune

During August 16 and 17, 1989, the Voyager 2 narrow-angle camera was used to photograph Neptune almost continuously, recording approximately two and one-half rotations of the planet. These images represent the most complete set of full disk Neptune images that the spacecraft will acquire. This picture from the sequence shows two of the four cloud features which have been tracked by the Voyager cameras during the past two months. The large dark oval near the western limb (the left edge) is at a latitude of 22 degrees south and circuits Neptune every 18.3 hours. The bright clouds immediately to the south and east of this oval are seen to substantially change their appearances in periods as short as four hours. The second dark spot, at 54 degrees south latitude near the terminator (lower right edge), circuits Neptune every 16.1 hours. This image has been processed to enhance the visibility of small features, at some sacrifice of color fidelity.

Image credit: NASA/JPL

Note: For more information, see NASA Pluto-Bound Spacecraft Crosses Neptune's Orbit, 25 Years After Neptune: Reflections on Voyager, and New Horizons Crosses the Orbit of Neptune.

Voyager 2 Flyby of Triton

NASA's Voyager 2 spacecraft gave humanity its first glimpse of Neptune and its moon Triton in the summer of 1989. Like an old film, Voyager's historic footage of Triton has been "restored" and used to construct the best-ever global color map of that strange moon (See PIA18668). The map, produced by Dr. Paul Schenk, a scientist at the Lunar and Planetary Institute in Houston, has also been used to make this movie recreating that historic Voyager encounter, which took place 25 years ago, on August 25, 1989.

Video credit: NASA/JPL-Caltech/Lunar & Planetary Institute

Note: For more information, see PIA18668: Map of Triton and Voyager Map Details Neptune's Strange Moon Triton.

Jupiter and Its Not-So-Great Red Spot

Jupiter's Great Red Spot is a churning anticyclonic storm. It shows up in images of the giant planet as a conspicuous deep red eye embedded in swirling layers of pale yellow, orange and white. Winds inside this Jovian storm rage at immense speeds, reaching several hundreds of kilometers per hour.

Historic observations as far back as the late 1800s gauged this turbulent spot to span about 41 000 kilometers at its widest point – wide enough to fit three Earths comfortably side by side. In 1979 and 1980 the NASA Voyager fly-bys measured the spot at a shrunken 23,335 kilometers across. Now, Hubble has spied this feature to be smaller than ever before.

This full-disc image of Jupiter was taken on 21 April 2014 with Hubble's Wide Field Camera 3 (WFC3).

Image credit: NASA, ESA, and A. Simon (Goddard Space Flight Center)

Note: For more information, see The Shrinking of Jupiter's Great Red Spot, Jupiter's Great Red Spot is Smaller Than Ever Measured, and Jupiter's Great Red Spot is Shrinking.

Ganymede Geological Map

Animation of a rotating globe of Jupiter's moon Ganymede, with a geologic map superimposed over a global color mosaic. The 37-second animation begins as a global color mosaic image of the moon then quickly fades in the geologic map.

The views incorporate the best available imagery from NASA's Voyager 1 and 2 spacecraft and NASA's Galileo spacecraft.

To present the best information in a single view of Jupiter's moon Ganymede, a global image mosaic was assembled, incorporating the best available imagery from NASA's Voyager 1 and 2 spacecraft and NASA's Galileo spacecraft. This image shows Ganymede centered at 200 west longitude. This mosaic (right) served as the base map for the geologic map of Ganymede (left).

Video credit (top): USGS Astrogeology Science Center/Wheaton/ASU/NASA/JPL-Caltech; image credit (bottom): USGS Astrogeology Science Center/Wheaton/NASA/JPL-Caltech

Note: For more information, see Largest Solar System Moon Detailed in Geologic Map.

Neptune's New Moon, S/2004 N1

NASA's Hubble Space Telescope has discovered a new moon orbiting the distant blue-green planet Neptune, the 14th known to be circling the giant planet.

The moon, designated S/2004 N 1, is estimated to be no more than 12 miles across, making it the smallest known moon in the Neptunian system. It is so small and dim that it is roughly 100 million times fainter than the faintest star that can be seen with the naked eye. It even escaped detection by NASA's Voyager 2 spacecraft, which flew past Neptune in 1989 and surveyed the planet's system of moons and rings.

Mark Showalter of the SETI Institute in Mountain View, California, found the moon July 1, while studying the faint arcs, or segments of rings, around Neptune. "The moons and arcs orbit very quickly, so we had to devise a way to follow their motion in order to bring out the details of the system," he said. "It's the same reason a sports photographer tracks a running athlete -- the athlete stays in focus, but the background blurs."

The method involved tracking the movement of a white dot that appears over and over again in more than 150 archival Neptune photographs taken by Hubble from 2004 to 2009.

On a whim, Showalter looked far beyond the ring segments and noticed the white dot about 65,400 miles from Neptune, located between the orbits of the Neptunian moons Larissa and Proteus. The dot is S/2004 N 1. Showalter plotted a circular orbit for the moon, which completes one revolution around Neptune every 23 hours.

For images, video, and more information Neptune's new moon, visit: http://hubblesite.org/news/2013/30

Image credit: NASA, ESA, M. Showalter/SETI Institute

Signs Changing Fast for Voyager at Solar System Edge

Two of three key signs of changes expected to occur at the boundary of interstellar space have changed faster than at any other time in the last seven years, according to new data from NASA's Voyager 1 spacecraft.

For the last seven years, Voyager 1 has been exploring the outer layer of the bubble of charged particles the sun blows around itself. In one day, on July 28, data from Voyager 1's cosmic ray instrument showed the level of high-energy cosmic rays originating from outside our solar system jumped by five percent. During the last half of that same day, the level of lower-energy particles originating from inside our solar system dropped by half. However, in three days, the levels had recovered to near their previous levels.

A third key sign is the direction of the magnetic field, and scientists are eagerly analyzing the data to see whether that has, indeed, changed direction. Scientists expect that all three of these signs will have changed when Voyager 1 has crossed into interstellar space. A preliminary analysis of the latest magnetic field data is expected to be available in the next month.

"These are thrilling times for the Voyager team as we try to understand the quickening pace of changes as Voyager 1 approaches the edge of interstellar space," said Edward Stone, the Voyager project scientist based at the California Institute of Technology, Pasadena, California. "We are certainly in a new region at the edge of the solar system where things are changing rapidly. But we are not yet able to say that Voyager 1 has entered interstellar space."

The levels of high-energy cosmic ray particles have been increasing for years, but more slowly than they are now. The last jump -- of five percent -- took one week in May. The levels of lower-energy particles from inside our solar system have been slowly decreasing for the last two years. Scientists expect that the lower-energy particles will drop close to zero when Voyager 1 finally crosses into interstellar space.

"The increase and the decrease are sharper than we've seen before, but that's also what we said about the May data," Stone said. "The data are changing in ways that we didn't expect, but Voyager has always surprised us with new discoveries."

Voyager 1, which launched on September 5, 1977, is 11 billion miles (18 billion kilometers) from the sun. Voyager 2, which launched on August 20, 1977, is close behind, at 9.3 billion miles (15 billion kilometers) from the sun.

"Our two veteran Voyager spacecraft are hale and healthy as they near the 35th anniversary of their launch," said Suzanne Dodd, Voyager project manager based at NASA's Jet Propulsion Laboratory, Pasadena. "We know they will cross into interstellar space. It's just a question of when."

Illustration credit: NASA/JPL-Caltech

Note: This story was actually released by JPL on August 3rd, but had to be pushed back due to other stories, especially those related to Curiosity.

Voyagers in the Heliosheath

This artist's concept shows NASA's two Voyager spacecraft exploring a turbulent region of space known as the heliosheath, the outer shell of the bubble of charged particles around our sun. After more than 33 years of travel, the two Voyager spacecraft will soon reach interstellar space, which is the space between stars.

Our sun gives off a stream of charged particles that form a bubble around our solar system known as the heliosphere. The solar wind travels at supersonic speeds until it crosses a shockwave called the termination shock. That part of our solar system is shown in dark blue. Voyager 1 crossed the termination shock in December 2004 and Voyager 2 did so in August 2007. Beyond the termination shock is the heliosheath, shown in gray, where the solar wind dramatically slows down and heats up. Outside those two areas is territory dominated by the interstellar wind, which is blowing from the left in this image. As the interstellar wind approaches the heliosphere, a bow shock forms, indicated by the bright arc.

Illustration credit: NASA/JPL-Caltech

Note: For more information, see Data From NASA's Voyager 1 Point to Interstellar Future.

Mapping the Heliosphere

Data from NASA's Cassini spacecraft have enabled scientists to create this map of the heliosphere, the bubble of charged particles around our Sun.

Charged particles stream out from our Sun in a phenomenon known as solar wind. The solar wind interacts with the matter between stars, which is known as the interstellar medium. The mingling of interstellar medium and solar wind creates particles called energetic neutral atoms, which stream back towards the Sun.

The ion and neutral camera on Cassini's magnetospheric imaging instrument detects energetic neutral atoms. This map shows those in the range of 5,200 to 13,500 electron volts. The regions with the highest intensity of particles are red and those with the lowest intensity of particles are blue.

Cassini detects a different spectrum of energetic neutral atoms than NASA's Interstellar Boundary Explorer (IBEX) does. The IBEX images show lower-energy particles. NASA's Voyager mission collects data on energetic ions in the region that is the source of the energetic neutral atoms.

The area where IBEX found a ribbon of high-intensity particles is outlined in white. The locations of Voyager 1 and Voyager 2 are indicated with the labels "V1" and "V2." The label "nose" indicates the direction that our solar system is traveling through the interstellar medium. The label "tail" indicates the region in the direction opposite the nose.

Image credit: NASA/JPL/JHUAPL

Jupiter's Great Red Spot

This Voyager 2 image shows the region of Jupiter extending from the equator to the southern polar latitudes in the neighborhood of the Great Red Spot. A white oval, different from the one observed in a similar position at the time of the Voyager 1 encounter, is situated south of the Great Red Spot. The region of white clouds now extends from east of the red spot and around its northern boundary, preventing small cloud vortices from circling the feature. The disturbed region west of the red spot has also changed since the equivalent Voyager 1 image. It shows more small scale structure and cloud vortices being formed out of the wave structures. The picture was taken on July 3, 1979 from 6 million kilometers (3.72 million miles).

Photo credit: NASA/JPL

Flight over Triton

This simulated voyage over the surface of Neptune's large moon Triton was produced using topographic maps derived from images acquired by NASA's Voyager spacecraft during its August 1989 flyby, 20 years ago.

Triton was the last solid object visited by the Voyager 2 spacecraft on its epic 10-year tour of the outer solar system. Voyager mapped only the hemisphere that faces Neptune, but revealed a very young surface scarred by rising blobs of ice (diapirs), faults, and volcanic pits and lava flows composed of water and other ices. The video begins near the western edge of this hemisphere with an approach over cantaloupe terrain and two large smooth walled plains. The video tracks due east for roughly 1500 kilometers over a large province of volcanic pits, calderas and smooth plains. As can be seen in this video, Triton is locally very rugged (with pits and mounds that are typically a few hundred meters [several hundred feet] high), but has no large mountains or deep basins and regional relief is low. The lack of large topographic features is a consequence of Triton's high internal heat and the low strength of most ices.

The video was produced by using a new topographic map of Triton, combined with a 1.65-kilometer resolution image mosaic. Topographic mapping was based on shape-from-shading analysis of the original Voyager images. Vertical relief has been exaggerated by a factor of 25 to aid interpretation.

Video credit: NASA/JPL/Universities Space Research Association/Lunar & Planetary Institute

Earth and Moon by Voyager 1

This picture of a crescent-shaped Earth and Moon -- the first of its kind ever taken by a spacecraft -- was recorded September 18, 1977, by NASA's Voyager 1 when it was 7.25 million miles (11.66 million kilometers) from Earth. The Moon is at the top of the picture and beyond the Earth as viewed by Voyager. In the picture are eastern Asia, the western Pacific Ocean and part of the Arctic. Voyager 1 was directly above Mt. Everest (on the night side of the planet at 25 degrees North latitude) when the picture was taken. The photo was made from three images taken through color filters, then processed by the Jet Propulsion Laboratory's Image Processing Lab. Because the Earth is many times brighter than the Moon, the Moon was artificially brightened by a factor of three relative to the Earth by computer enhancement so that both bodies would show clearly in the print. Voyager 2 was launched August 20, 1977, followed by Voyager 1 on September 5, 1977, en route to encounters at Jupiter in 1979 and Saturn in 1980 and 1981.

Photo credit: NASA/JPL

Ariel

This picture is part of the highest-resolution Voyager 2 imaging sequence of Ariel, a moon of Uranus about 1,300 kilometers (800 miles) in diameter. The clear-filter, narrow-angle image was taken January 24, 1986, from a distance of 130,000 km (80,000 mi). The complexity of Ariel's surface indicates that a variety of geologic processes have occurred. The numerous craters, for example, are indications of an old surface bombarded by meteoroids over a long period. Also conspicuous at this resolution, about 2.4 km (1.5 mi), are linear grooves (evidence of tectonic activity that has broken up the surface) and smooth patches (indicative of deposition of material).

Photo credit: NASA/JPL

Voyager 2 at 12,000 Days

NASA's plucky Voyager 2 spacecraft has hit a long-haul operations milestone today (June 28) -- operating continuously for 12,000 days. For nearly 33 years, the venerable spacecraft has been returning data about the giant outer planets, and the characteristics and interaction of solar wind between and beyond the planets. Among its many findings, Voyager 2 discovered Neptune's Great Dark Spot and its 450-meter-per-second (1,000-mph) winds.

The two Voyager spacecraft have been the longest continuously operating spacecraft in deep space. Voyager 2 launched on August 20, 1977, when Jimmy Carter was president. Voyager 1 launched about two weeks later on September 5. The two spacecraft are the most distant human-made objects, out at the edge of the heliosphere -- the bubble the sun creates around the solar system. Mission managers expect Voyager 1 to leave our solar system and enter interstellar space in the next five years or so, with Voyager 2 on track to enter interstellar space shortly after that.

Having traveled more than 21 billion kilometers (13 billion miles) on its winding path through the planets toward interstellar space, the spacecraft is now nearly 14 billion kilometers (9 billion miles) from the sun. A signal from the ground, traveling at the speed of light, takes about 12.8 hours one-way to reach Voyager 2.

Voyager 1 will reach this 12,000-day milestone on July 13, 2010 after traveling more than 22 billion kilometers (14 billion miles). Voyager 1 is currently more than 17 billion kilometers (11 billion miles) from the sun.

Image Credit: NASA/JPL/California Institute of Technology

Voyager 2 and the "Aliens"

The Minister is occasionally perplexed by the silliness some people say. In late April (last month), NASA engineers announced that the spacecraft Voyager 2 was having some software errors in its transmissions back home to Earth:

Engineers have shifted NASA's Voyager 2 spacecraft into a mode that transmits only spacecraft health and status data while they diagnose an unexpected change in the pattern of returning data. Preliminary engineering data received on May 1 show the spacecraft is basically healthy, and that the source of the issue is the flight data system, which is responsible for formatting the data to send back to Earth. The change in the data return pattern has prevented mission managers from decoding science data.

The first changes in the return of data packets from Voyager 2, which is near the edge of our solar system, appeared on April 22. Mission team members have been working to troubleshoot and resume the regular flow of science data. Because of a planned roll maneuver and moratorium on sending commands, engineers got their first chance to send commands to the spacecraft on April 30. It takes nearly 13 hours for signals to reach the spacecraft and nearly 13 hours for signals to come down to NASA's Deep Space Network on Earth. (Source)

Considering that the two Voyager spacecraft have been in flight for 33 years (Voyager 2 was launched on August 20, 1977), the occasional software glitch is a very minor hiccup for such an old but functional spacecraft.

But some people, instead of viewing the problem rationally, choose to let their imaginations run rampant:

German researcher Hartwig Hausdorf has chalked up the problem to aliens. To be specific, he posits that the Voyager 2 was hijacked by aliens. According to Bild.com, Hausdorf said

"It seems almost as if someone had reprogrammed or hijacked the probe – thus perhaps we do not yet know the whole truth…”

Bild writer Attila Albert speculated that the Golden Record might have attracted the aliens.

Really now! Aliens have hijacked Voyager 2! Tell me, Herr Hausdorf, don't you think you should take off that aluminum foil cap you're wearing?

Image credits:
Top: NASA/JPL-Caltech
Bottom: Touchstone Pictures/Blinding Edge Pictures/The Kennedy/Marshall Company

HT: Digital Journal

Neptune, by Voyager 2

Credit: NASA


While Neptune may be the farthest of the eight planets orbiting the Sun (as defined by the International Astronomical Union (IAU)), it certainly doesn't lack for interesting features. While Uranus' atmosphere is primarily a mix of hydrogen, helium and methane (the last giving the planet its light blue hue), Neptune's atmosphere is primarily made up of methane, which is what gives the planet its deep blue color. Neptune is the smallest of the four gas giants, but it's also the densest of that set.

Although Neptune receives only 3% as much sunlight as Jupiter, it showed several large dark spots reminiscent of Jupiter's hurricane-like storms. The largest spot is named the "Great Dark Spot" and is an anticyclone similar to Jupiter's Great Red Spot. Neptune's Great Dark Spot is comparable in size, relative to the planet, and at the same latitude (22° South latitude) as Jupiter's Great Red Spot. However, Neptune's Great Dark Spot is far more variable in size and shape than the Great Red Spot. Another spot, named "D2" by the Voyager 2 scientists, is located far to the south of the Great Dark Spot, at 55° South latitude. It is almond-shaped, with a bright central core, and moves eastward around the planet in about 16 hours.

Most of the winds on Neptune blow in a westward direction, which is retrograde, or opposite to the rotation of the planet. Near the Great Dark Spot, there are retrograde winds blowing up to 1,500 miles an hour (2,400 kph) -- the strongest winds measured on any planet, including windy Saturn.

The only spacecraft to date to fly past Neptune was Voyager 2, which hurtled past Neptune's north pole on August 25, 1989. Voyager 2's closest approach was a mere 4,950 km from the planet, the closest approach Voyager 2 made of any planet. The fly-by of Neptune put Voyager 2 on a course 48° south of the ecliptic plane of the solar system, roughly toward the constellation Canis Major and the star Sirius, with a rate of speed about 470 million km per year.

Uranus, by Voyager 2

Credit: NASA

The fly-by of Voyager 2 past the planet Uranus should have been one of excitement and wonder as it had been in July 1979 and August/September 1981, when Voyager passed by the planets Jupiter and Saturn, respectively. However, four days after Voyager's closest approach to Uranus, the Space Shuttle Challenger was destroyed and the new discoveries from the outer solar system were quickly ignored in the wake of the tragedy.

This photo was taken by Voyager 2 on January 25, 1986, the day after the closest approach, at a distance of 600,000 miles (about 965,000 km). Voyager 2 is still operational, over 40 years after its launch, and is over 85.039 Astronomical Units (AU) or 7.9 billion miles (12.7 billion km) away from the Sun at this time.