A Tale of Two Tails:Distortions in Comet Tails and Ship “Tails”, i.e., Turbulent Ship Wakes

Tail Number One: In December 2011, NASA’s Solar Dynamics Observatory [ref. 1] imaged Comet Lovejoy’s tail as the comet passed close to the sun. When a comet’s orbit takes a comet close to the Sun, the comet in such an orbit is referred to as a Sun grazing comet. NASA reported, “wriggles” were seen in the Comet Lovejoy’s tail as the comet passed through the Sun’s atmosphere. The explanation for the wriggles included the possibility of buffeting by plasma waves in the Sun’s atmosphere, or corona, or perhaps the effects of strong magnetic fields looping out of the Sun’s surface up into the corona. The slides shown below that are numbered 1 to 8 are SOHO images [ref. 2] of Comet Lovejoy’s encounter with the Sun’s corona. Those slides are duplicated in the series labeled 1a to 8a with the inclusion of a blue box enclosing Comet Lovejoy’s tail. The portion in that series of images enclosed in the boxes are magnified and shown in the series of slides numbered 1b to 8b in an attempt to focus on the distortions in Comet Lovejoy’s tail. All can be “flipped through” with Microsoft PowerPoint Slide Show feature to capture the time variability in the comet’s tail.

Tail Number Two: The turbulent wake of ships form a “tail” behind a ship. Such a ship “tail” is different from the familiar Kelvin wake [ref. 3] and is easily seen in Synthetic Aperture Radar (SAR) images of the ocean surface long after a ship has passed through. The slides further below and labeled 1c to 4c shows examples of SAR images of ship wakes [ref. 4]. Those slides show “wriggles” in the turbulent ship wake produces by flow irregularities at the ocean surface [ref. 5].

Other “Tails”: The wriggles in the comet’s tail are not unlike those in the contrails of airliners at cruising altitudes and those contrail distortions from a straight line are caused by flow processes in our Earth’s atmosphere. {see contrail cases at, for example, these sites: https://www.google.com/?gws_rd=ssl#q=contrails+distortions+pictures and http://contrailscience.com/contrail-photos-through-history/ )

Note: This is a for fun comparison between vastly diverse objects in immensely dissimilar physical environments simply to show a similarity in distortions of a feature that one might call a “tail”. A personnel fascination with comets and with a study of turbulent ship

wakes with SAR is the motivation behind this text. The point is to show that vastly dissimilar physical systems in significantly different physical environments undergo a similar perturbation in “tail” features under much different time, composition, size and distance scales.

References:

1.) http://sdo.gsfc.nasa.gov/

2.) http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/

3.) For a good discussion on Kelvin wakes, see, for example, Linear and Nonlinear Waves by G.B. Whitham, John Wiley and Sons, 1974 edition, pages 409-414.

4.) Ochadlick, A. R., Jr., P. Cho, and Jeannette Evans-Morgis, SAR Observations of Currents Co-located with Slicks, J. of Geophys. Res., Vol. 97, No. C4, p. 5325-5330, 1992.

5.) Ochadlick, A. R., Jr., SAR Ocean Imagery for Submesoscale Plate Model (abstract), EOS Trans. AGU, Vol. 72, No. 17, p.149, 1991.

Additional Information: Showstack, Randy, Spacecraft Improves Understanding of Turbulent “Interface” Region of the Sun, EOS, Transactions, American Geophysical Union, Vol. 94, No. 51, page 497, 17 December 2013

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

1

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

2

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

3

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

4

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

5

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

6

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

7

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

8

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

1a

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

2a

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

3a

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

4a

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

5a

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

6a

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

7a

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/“Dec. 16, 2011: This morning, an armada of spacecraft witnessed something that many experts thought impossible.  Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact.”“NASA's Solar Dynamics Observatory caught Comet Lovejoy emerging from its scorching close encounter with the sun.”“In the SDO movies, the comet's tail wriggles wildly as the comet plunges through the sun's hot atmosphere only 120,000 km above the stellar surface. This could be a sign that the comet was buffeted by plasma waves coursing through the corona.  Or perhaps the tail was bouncing back and forth off great magnetic loops known to permeate the sun's atmosphere.  No one knows.”

8a

1b

2b

3b

4b

5b

6b

7b

8b

The SAR image on the left shows a “young” ship wake (i.e., trail) and the arrow points out a distortion in the wake produced by activity associated by the dark “slick”. The SAR image on the right shows the same ocean region at a later time (as seen by the time scale) and the ship wake has now distorted even further. The distance scale’s “0” refers to the nadir point under the aircraft containing the SAR system. The aircraft belonged to the Naval Air Development Center.

Each of these images is slightly enlarged in the following two slides, i.e., 2c and 3c.

1c

2c

3c

Another SAR image showing several ship “tails” (i.e., wakes) and for two of the “tails” the associated ship can be seen. The roughly horizontal wake across the center of the image shows two very obvious distortions

Ships producing “tails” (i.e., wakes)

Obvious distortions in ship “tails” (i.e., wakes)

4c