Rosetta blog: OSIRIS spots boulders in balancing act

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The 3 extraordinary boulders are found in a Aker segment of Comet 67P/C-G, on a comet's vast lobe (in a centre of a segment outlined). Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

The 3 extraordinary boulders are found in a Aker segment of Comet 67P/C-G, on a comet’s vast lobe (in a centre of a segment outlined). Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Image of a boulders taken by OSIRIS on 16 Sep 2014 from a stretch of 29 km. The picture scale during this stretch is 54 cm/pixel and a picture measures about 316 m across. Boulder 3 measures approximately 30 m across. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Image of a boulders taken by OSIRIS on 16 Sep 2014 from a stretch of 29 km. The picture scale during this stretch is around 0.5 m/pixel and a picture measures about 292 m across. Boulder 3 measures approximately 30 m across.
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Image of a boulders taken by OSIRIS on 16 Aug 2014 from a stretch of 105 kilometres. Boulder 3 measures approximately 30 m across. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Image of a boulders taken by OSIRIS on 16 Aug 2014 from a stretch of 105 kilometres. The picture has a fortitude of about 2 m/pixel. Boulder 3 measures approximately 30 m across.
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Image of a boulders taken by OSIRIS on 19 Sep 2014 from a stretch of about of 29 km. The picture scale during this stretch is 54 cm/pixel and a picture measures about 308 m across. Boulder 3 measures approximately 30 m across. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Image of a boulders taken by OSIRIS on 19 Sep 2014 from a stretch of about of 29 km. The picture scale during this stretch is about 0.5m/pixel and a picture measures about 285 m across. Boulder 3 measures approximately 30 m across.
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Scientists from Rosetta’s OSIRIS group have detected an surprising arrangement of boulders in a Aker segment on a vast lobe of Comet 67P/Churyumov-Gerasimenko. At initial peek they are suggestive of supposed “balancing rocks” on Earth.

Of a 3 boulders, a largest (labelled with a ‘3’) has a hole of approximately 30 metres. In an picture taken on 16 Sep 2014 (below), it stands out as carrying usually a really little hit area with a comet’s surface. It also seems to be perched on a edge of a little depression.

“We had beheld this arrangement already in progressing images, however, during initial a boulders did not seem to differ almost from others we had seen,” says OSIRIS scientist Sebastien Besse from ESA, who initial beheld a formation.

Similar geological formations are also found on Earth. Balancing rocks hold a underlying belligerent with usually a little fragment of their aspect and mostly demeanour as if they might lean or disintegrate over any moment. Some can indeed be rocked behind and onward and are afterwards referred to as “rocking stones.” Many of these boulders are supposed “erratics” that trafficked to their stream plcae within glaciers. In other cases, breeze and H2O eroded softer element in a internal bedrock, withdrawal usually a some-more resistant element behind.

“How this apparent balancing stone on Comet 67P/C-G was shaped is not transparent during this point,” says OSIRIS Principal Investigator Holger Sierks from a Max Planck Institute for Solar System Research (MPS) in Germany.

One probability is that ride processes associated to cometary activity played a role, causing such boulders to pierce from their strange site and strech a new location.

Scattered boulders are seen in many places on a comet’s surface, infrequently in differently comparatively well-spoken regions. One of a largest – Cheops – measures approximately 45 metres in stretch and sits in a center of a well-spoken partial of Imhotep on a underside of a comet’s vast lobe. In other regions, it is some-more common to see rubble piles comprising hundreds of boulders.

“Interpreting images of a comet’s aspect can be tricky,” adds Sierks. Depending on a observation angle, illumination, and spatial resolution, really opposite and infrequently even dubious impressions are created.

For example, in an picture taken on 16 Aug 2014 from a stretch of 105 kilometres, one of a smaller boulders [labelled ‘2’] in a balancing stone arrangement appears to be extending like a pillar. However, this sense is not reliable in an picture of a same segment taken on 19 Sep 2014 from a most closer stretch of 29 km. Similarly, interjection to a change in observation geometry between images, a coming of a vast stone also changes utterly dramatically, even between a 16 and 19 Sep images.

Further imaging of these formations should assistance yield some-more discernment into their loyal inlet and maybe even their origin.

 

 

Unlabelled versions of a images are also supposing next (all credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA):

ESA_Rosetta_OSIRIS_BalancingBoulders_context_unlabelledESA_Rosetta_OSIRIS_20140816ESA_Rosetta_OSIRIS_20140919ESA_Rosetta_OSIRIS_20140916

Source: Rosetta blog