Perihelion Cliff

From the location where it came to rest after bounces, the Philae lander of the European Space Agency's Rosetta mission captured this view of a cliff on the nucleus of comet 67P/Churyumov-Gerasimenko. The feature is called "Perihelion Cliff." The image is from the lander's CIVA camera.

Image credit: ESA/Rosetta/Philae/CIVA

Note: For more information, see
* PIA19094: Comet Lander's View During First Bounce
* PIA19096: Philae Lander's Setting on Comet's Surface
* PIA19097: Philae Lander's Setting on Comet, with Cliff-Image Inset
* Rosetta Orbiter to Swoop Down On Comet in February
* Rosetta to Swoop Down on Comet in February

Rosetta Comet Water Different From Earth Water

This composite is a mosaic comprising four individual NAVCAM images taken from 19 miles (31 kilometers) from the center of comet 67P/Churyumov-Gerasimenko on November 20, 2014. The image resolution is 10 feet (3 meters) per pixel.

The European Space Agency's Rosetta spacecraft has found the water vapor from comet 67P/Churyumov-Gerasimenko to be significantly different from that found on Earth. The discovery fuels the debate on the origin of our planet's oceans.

The measurements, by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument, were made in the month following the arrival of the spacecraft on August 6. It is one of the most anticipated early results of the mission, because the origin of Earth's water is still an open question.

Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. Rosetta's lander obtained the first images taken from a comet's surface and will provide analysis of the comet's possible primordial composition. Rosetta will be the first spacecraft to witness at close proximity how a comet changes as it is subjected to the increasing intensity of the sun's radiation. Observations will help scientists learn more about the origin and evolution of our solar system and the role comets may have played in seeding Earth with water, and perhaps even life.

Image and top paragraph text credit: ESA/Rosetta/NAVCAM; bottom three paragraph text credit: NASA/JPL

Note: For more information, see:
* First Measurements of Comet’s Water Ratio
* Rosetta Instrument Reignites Debate on Earth's Oceans
* Rosetta Fuels Debate on Origin of Earth's Oceans
* Rosetta Reignites Debate on Earth's Oceans

The Disintegration of Comet ISON

Some had hoped comet ISON would be the comet of the century, lighting Earth’s skies during the latter months of 2013. Instead, it was barely visible for ground-based observers, but the Solar and Heliospheric Observatory (SOHO) had a ring-side seat to watch its disintegration.

This image is a montage spanning three days from 28–30 November 2013. The comet enters the image at the lower right, passes round the Sun and exits the frame towards the upper right. The bright star to the lower left is the red supergiant star Antares.

Astronomers had been tracking the comet for more than a year as it edged closer to the Sun, and by late November it had passed into the field of view of SOHO’s LASCO C3 camera. It was to skim the Sun, just 1,165,000 km above the fiery surface.

This is approximately 50 times closer to the Sun than innermost planet Mercury, and the comet was officially termed a ‘sungrazer’. If it survived the encounter it was expected to become extremely bright and be a well-placed object, visible to the naked eye in Earth’s night sky.

Calculations based on its orbit show that ISON began its journey towards the Sun about 3 million years ago, dislodged from its distant orbit by a passing star. Now, its fate would be sealed within days.

On 27 November, the comet brightened dramatically by a factor of about ten. Yet just before it reached closest approach to the Sun, it began to fade. This was a strong indicator that the heart of the comet, the icy nucleus, had broken up. Many expected it would disperse completely but, at first, it looked as if they were wrong.

Comet ISON appeared to survive the close approach, emerging on the other side of the Sun. Some still hoped for a bright display in the night skies. But they were to be disappointed. Quickly, the comet began to disappear. A recent analysis of SOHO data showed that the nucleus had indeed disintegrated just before closest approach to the Sun. Nothing appreciable was left of it, just a lot of dust and vapor.

The disintegration of comet ISON provided scientists with an exceptional chance to see a comet inside and out. Another rare opportunity is being provided by comet 67P/Churyumov-Gerasimenko. ESA’s Rosetta spacecraft caught up with this comet early in August 2014 and deployed the lander Philae to the surface in November. The orbiter will accompany comet 67P/C-G along its orbit and through its closest approach to the Sun, which takes it between the orbits of Mars and Earth. While this comet is unlikely to suffer the same fate as comet ISON, it will provide an unsurpassed insight into the nature of comets.

Image credit: ESA/NASA

Philae Drifting Across Comet 67P/Churyumov-Gerasimenko

These incredible images show the breathtaking journey of Rosetta’s Philae lander as it approached and then rebounded from its first touchdown on Comet 67P/Churyumov–Gerasimenko on 12 November 2014.

The mosaic comprises a series of images captured by Rosetta’s OSIRIS camera over a 30 minute period spanning the first touchdown. The time of each of image is marked on the corresponding insets and is in GMT. A comparison of the touchdown area shortly before and after first contact with the surface is also provided.

The images were taken with Rosetta’s OSIRIS narrow-angle camera when the spacecraft was 17.5 km from the comet center, or roughly 15.5 km from the surface. They have a resolution of 28 cm/pixel and the enlarged insets are 17 x 17 m.

From left to right, the images show Philae descending towards and across the comet before touchdown. The image taken after touchdown, at 15:43 GMT, confirms that the lander was moving east, as first suggested by the data returned by the CONSERT experiment, and at a speed of about 0.5 m/s.

The final location of Philae is still not known, but after touching down and bouncing again at 17:25 GMT, it reached there at 17:32 GMT. The imaging team is confident that combining the CONSERT ranging data with OSIRIS and navcam images from the orbiter and images from near the surface and on it from Philae’s ROLIS and CIVA cameras will soon reveal the lander’s whereabouts.

The insets are provided separately via the blog: OSIRIS spots Philae drifting across the comet.

Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Note: For more information, see:
* PIA18875: First Touchdown Site of Comet Lander
* PIA18879: First Panoramic View from Comet Lander
* PIA18897: Rosetta Lander Captured Before/After Bounce
* First Touchdown
* Philae Spotted by Rosetta After First Landing
* Searching for Philae
* First Comet Panoramic
* First Touchdown Close-Up 1
* Three Touchdowns for Rosetta's Lander
* Pioneering Philae Completes Main Mission Before Hibernation
* Rosetta's 'Philae' Makes Historic First Landing on a Comet
* Rosetta's Comet Lander Landed Three Times
* Philae Landing: Acquisition of Signal from Spacecraft and Lander (Video)
* Philae Landing: Touchdown Highlights (Video)
* Philae Touchdown: Lander Status and First Descent Image (Video)
* OSIRIS Spots Philae Drifting Across the Comet

Comet 67P/Churyumov-Gerasimenko During Philae's Descent

This image of comet 67P/Churyumov-Gerasimenko was acquired by the Philae lander of the European Space Agency's Rosetta mission during Philae's descent toward the comet on November 12, 2014. Philae's ROLIS (ROsetta Lander Imaging System) took the image at 14:38:41 UTC (6:38:41 a.m., PST) at a distance of approximately two miles (three kilometers) from the surface. The landing site is imaged with a resolution of about 10 feet (three meters) per pixel.

The ROLIS instrument is a down-looking imager that acquires images during the descent and doubles as a multi-spectral close-up camera after the landing. The aim of the ROLIS experiment is to study the texture and microstructure of the comet's surface. It was developed by the German Aerospace Center's Institute of Planetary Research, Berlin.

The lander separated from the orbiter at 09:03 UTC (1:03 a.m. PST) for touch down on comet 67P seven hours later.

Rosetta and Philae had been riding through space together for more than 10 years. Philae is the first probe to achieve a soft landing on a comet, and Rosetta is the first to rendezvous with a comet and follow it around the sun. The information collected by Philae at one location on the surface will complement that collected by the Rosetta orbiter for the entire comet.

Image credit: ESA/Rosetta/Philae/DLR

Note: This is the major story for today, and just the ESA and NASA by themselves have numerous news stories, photos and videos available. For more information, see:
* How to Land on a Comet
* PIA18871: Rosetta Mission Selfie at 10 Miles
* PIA18872: Rosetta Mission Selfie at 30 Miles
* PIA18873: Farewell, Philae
* PIA18870: Farewell Shot of Rosetta by Philae Lander
* European Spacecraft Set to Harpoon a Comet Today
* Separation
* Confirmation of Separation of the Philae Lander from Rosetta
* Separation Signal Confirmed
* Farewell Rosetta
* Farewell Philae - Narrow-Angle View (1)
* Farewell Philae - Narrow-Angle View (2)
* Farewell Philae - Wide-Angle View
* Philae Descending to the Comet – Wide-Angle View
* Lander Departure
* ROLIS Descent Image
* Highlights: Rosetta Mission Comet Landing Up to Lander Separation (Video)
* Rosetta and Philae Go for Separation
* Rosetta and Philae Separation Confirmed
* Confirmation of Separation of the Philae Lander from Rosetta
* Touchdown! Rosetta's Philae Probe Lands on Comet

Smooth Terrain on Comet 67P/Churyumov-Gerasimenko

A patch of relatively smooth ground on the nucleus surface of comet 67P/Churyumov-Gerasimenko appears in this image taken by the navigation camera on the European Space Agency's Rosetta spacecraft during the second half of October 2014. The spacecraft has been orbiting this comet since August 2014 and will release its lander, Philae, on November 12 to land on the comet's nucleus.

This image was taken from a distance of less than six miles (10 kilometers) from the surface. It is one of a series of images from Rosetta's navigation camera showing the varied and dramatic terrain of the nucleus. Some light contrast enhancements have been made to emphasize certain features and to bring out features in the shadowed areas. In reality, the comet is extremely dark - blacker than coal. The images, taken in black-and-white, are grey-scaled according to the relative brightness of the features observed, which depends on local illumination conditions, surface characteristics and composition of the given area.

Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. Rosetta's lander will obtain the first images taken from a comet's surface and will provide the first analysis of a comet's composition by drilling into the surface. Rosetta also will be the first spacecraft to witness at close proximity how a comet changes as it is subjected to the increasing intensity of the sun's radiation. Observations will help scientists learn more about the origin and evolution of our solar system and the role comets may have played in seeding Earth with water, and perhaps even life.

Image credit: ESA/Rosetta/NAVCAM

Note: For more information, see PIA18867: Jagged Horizon on Rosetta's Destination Comet and PIA18869: Rough Terrain on Rosetta's Destination Comet.

Artist’s Impression of Bright Exozodiacal Light

This artist’s view from an imagined planet around a nearby star shows the brilliant glow of exozodiacal light extending up into the sky and swamping the Milky Way. This light is starlight reflected from hot dust created as the result of collisions between asteroids, and the evaporation of comets. The presence of such thick dust clouds in the inner regions around some stars may pose an obstacle to the direct imaging of Earth-like planets in the future.

Illustration credit: ESO/L. Calçada

Note: For more information, see VLTI Detects Exozodiacal Light.

Comet 67P/Churyumov-Gerasimenko's Jets

This image of 67P/Churyumov-Gerasimenko was taken by the Optical, Spectroscopic, and Infrared Remote Imaging System, Rosetta's main onboard scientific imaging system, on September 10, 2014. Jets of cometary activity can be seen along almost the entire body of the comet.

Image credit: ESA/Rosetta/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Note: For more information, see PIA18835: Rosetta Comet Spreads its Jets, Comet activity – 10 September 2014, Rosetta's Comet Scrambling Its Jets(JPL), and Rosetta Comet Scrambles its Jets (NASA Science News).

Boulder Cheops

This image of the surface of Comet 67P/Churyumov-Gerasimenko was taken by Rosetta’s OSIRIS narrow-angle camera on 19 September 2014, from a distance of 28.5 km.

The image features a large boulder casting a long shadow on the surface of the comet. The boulder has a maximum dimension of about 45 meters and is the largest structure within a group of boulders located on the lower side of the comet’s larger lobe. This cluster of boulders reminded scientists of the famous pyramids at Giza near Cairo in Egypt, and thus it has been named Cheops for the largest of those pyramids, the Great Pyramid, which was built as a tomb for the pharaoh Cheops (also known as Kheops or Khufu) around 2550 BC.

Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Comet 67P/Churyumov-Gerasimenko (30 September 2014)

Four-image montage comprising images taken by Rosetta's navigation camera on 30 September from a distance of 18.1 km from the center of Comet 67P/Churyumov-Gerasimenko. Each of the four frames making up the montage measures about 1.4 kilometers across. The image features Site J, the primary landing site for Rosetta’s lander Philae.

Image credit: ESA/Rosetta/NAVCAM

Comet 67P/Churyumov-Gerasimenko's Dimensions

Comet 67P/Churyumov-Gerasimenko's dimensions, as measured from images taken by Rosetta's OSIRIS imaging system. The images shown in the graphic were taken by Rosetta's navigation camera on 19 August.

The larger lobe of the comet measures 4.1 x 3.2 x 1.3 km, while the smaller lobe is 2.5 x 2.5 x 2.0 km.

More details via the blog: Measuring Comet 67P/C-G

Credits: Image: ESA/Rosetta/NAVCAM; Dimensions: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Comet 67P/Churyumov-Gerasimenko Jets Firing (26 September 2014)

The four images that make up a new montage of comet 67P/Churyumov-Gerasimenko were taken on September 26, 2014 by the European Space Agency's Rosetta spacecraft. At the time, Rosetta was about 16 miles (26 kilometers) from the center of the comet.

In the montage, a region of jet activity can be seen at the neck of the comet. These jets, originating from several discrete locations, are a product of ices sublimating and gases escaping from inside the nucleus.

The overlapping and slightly dissimilar angles of the four images that compose the montage are a result of the combined effect of the comet rotating between the first and last images taken in the sequence (about 10 degrees over 20 minutes), and the spacecraft movement during that same time.

Launched in March 2004, Rosetta was reactivated in January 2014 after a record 957 days in hibernation. Rosetta is composed of an orbiter and lander. Its objectives since arriving at comet 67P/Churyumov-Gerasimenko earlier this month are to study the celestial object up close in unprecedented detail, prepare for landing a probe on the comet's nucleus in November, and after the landing, track the comet's changes through 2015 as it sweeps past the sun.

Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. Rosetta's lander will obtain the first images taken from a comet's surface and will provide comprehensive analysis of the comet's possible primordial composition by drilling into the surface. Rosetta also will be the first spacecraft to witness at close proximity how a comet changes as it is subjected to the increasing intensity of the sun's radiation. Observations will help scientists learn more about the origin and evolution of our solar system and the role comets may have played in seeding Earth with water, and perhaps even life.

Image credit: ESA/Rosetta

Note: For more information, see Rosetta Comet Fires Its Jets.

Comet 67P/Churyumov-Gerasimenko (26 September 2014)

Four-image montage comprising images taken by Rosetta's navigation camera on 26 September from a distance of 26.3 km from Comet 67P/Churyumov-Gerasimenko. The comet nucleus is about 4 km across.

The image shows the spectacular region of activity at the 'neck' of 67P/C-G. This is the product of ices sublimating and gases escaping from inside the comet, carrying streams of dust out into space.

Image credit: ESA/Rosetta/NAVCAM

Landing Site J - Comet 67P/Churyumov-Gerasimenko (21 September 2014)

Rosetta's navigation camera (NAVCAM) took this image of Comet 67P/Churyumov-Gerasimenko on 21 September, from a distance of 27.8 km from the comet center. The image covers an area of about 2 x 1.9 km and focuses on the smaller of the two comet lobes. The primary landing site J is 'above' the distinctive depression in this view. Click here for a context image.

Image credit: ESA/Rosetta/NAVCAM

Note: For more information, see Rosetta to Deploy Lander on 12 November (ESA), Rosetta to Deploy Lander on November 12 (JPL), and Rosetta Mission Status.

Comet 67P/Churyumov-Gerasimenko (21 September 2014)

Single frame (and cropped) NAVCAM image of Comet 67P/Churyumov-Gerasimenko on 21 September 2014.

Image credit: ESA/Rosetta/NAVCAM

Comet 67P/Churyumov-Gerasimenko (24 September 2014)

Four-image NAVCAM mosaic of Comet 67P/Churyumov-Gerasimenko, using images taken on 24 September 2014 when Rosetta was 28.5 km from the comet.

Image credit: ESA/Rosetta/NAVCAM

Comet 67P/Churyumov-Gerasimenko (19 September 2014)

Four-image NAVCAM mosaic of Comet 67P/Churyumov-Gerasimenko, using images taken on 19 September 2014 when Rosetta was 28.6 km from the comet.

Image credit: ESA/Rosetta/NAVCAM

Philae Secondary Landing Site - Site C

Site C was chosen as the backup site for Rosetta’s lander Philae during the Landing Site Selection Group meeting held on 13–14 September 2014.

The image was taken by Rosetta's narrow-angle camera from a distance of about 70 km. The resolution is 1.5 meters/pixel.

Full story: 'J' marks the spot for Rosetta's lander

Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Note: For more information, see 'J' Marks the Spot for Rosetta's Lander.

Philae's Primary Landing Site - Site J

Philae’s primary landing site will target Site J, the center of which is indicated by the cross in this OSIRIS narrow-angle image.

Site J is located on the head of Comet 67P/Churyumov–Gerasimenko and is close to the candidate site B, the large depression to the right of the image.

Site J offers the minimum risk to the lander in comparison to the other candidate sites, and is also scientifically interesting, with signs of activity nearby. At Site J, the majority of slopes are less than 30º relative to the local vertical, reducing the chances of Philae toppling over during touchdown. Site J also appears to have relatively few boulders and receives sufficient daily illumination to recharge Philae and continue science operations on the surface beyond the initial battery-powered phase.

Full story: 'J' marks the spot for Rosetta's lander

Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Note: For more information, see:
* Philae’s Primary Landing Site Close-Up
* Philae’s Primary Landing Site in Context
* Philae’s Primary Landing Site in 3D
* 'J' Marks the Spot for Rosetta's Lander (ESA Science)
* PIA18809: Rosetta Lander's Primary Landing Site
* PIA18810: Rosetta Lander's Backup Landing Site
* 'J' Marks the Spot for Rosetta's Lander (JPL)
* Announcement of the Selected Rosetta Primary Landing Site and a Backup
* Replay: Rosetta Landing Site Announcement (Video)

For more information about Philae and the mission, see:
* Philae's Panoramic Camera
* Philae’s Descent and Science on the Surface
* How to Orbit a Comet (all of the above are videos)
* Rosetta and Philae at Comet

Comet 67P/Churyumov-Gerasimenko (11 August 2014) From Earth

Since early August 2014, Rosetta has been enjoying a close-up view of comet 67P/Churyumov–Gerasimenko. Meanwhile, astronomers on Earth have been busy following the comet with ground-based telescopes. As Rosetta is deep inside the ‘atmosphere’ coma – it was 100 km from the nucleus on 6 August, and has been getting much closer since then – the only way to view the whole comet is to ‘stand back’ and observe it from Earth.

This image was recorded on 11 August 2014 using one of the 8 m-diameter telescopes of the European Southern Observatory’s Very Large Telescope in Chile.

Although faint, the comet is clearly active, revealing a dusty coma extending at least 19,000 km from the nucleus. The comet's dusty veil is not symmetrical as the dust is swept away from the Sun – located beyond the lower-right corner of the image – to begin forming a tail.

At the moment, the comet is visible only from the southern hemisphere and, at more than 500 million km from the Sun, it is still very faint. In addition, it currently sits in a patch of the sky where it is camouflaged against the crowded starry background of the Milky Way. For these reasons, the image was compiled by superimposing 40 individual exposures, each lasting about 50 seconds, and removing background stars.

A large collaboration of astronomers across the world has been working to make the most of the unique opportunity to observe the comet from the ground while Rosetta is performing measurements at the comet. The Very Large Telescope is taking images every two nights on average. These short exposures monitor the comet’s activity by studying how its brightness changes. The results are used by the Rosetta team to help plan spacecraft operations.

Image credit: C. Snodgrass/ESO/ESA