Note # 1:  Yes, you're spot on correct.    Yesterday's featured mythological character was actually named Adep or Apep.
We chose the Greek name of this Egyptian god in order to tie it in with the asteroid of the same name.

Note # 2: Well, another partisan divide.  Our subscriber survey pertaining to the mythological yielded mixed results.
The mythological excursions are adored by some, tolerated by others, and, well, much less than adored by still others. 
Consequently, we will include mythological prefaces in some of the articles and omit them in others.  

THE SOUTHWORTH PLANETARIUM
207-780-4249   www.usm.maine.edu/planet
70 Falmouth Street   Portland, Maine 04103
43.6667° N                   70.2667° W 
Altitude:  10 feet below sea level
Founded January 1970
Julian Date:  2459305.18 
2020-2021: CIIII


THE DAILY ASTRONOMER
Wednesday, March 31, 2021
Exploratorium XXXVI:  Suez Canal Super Moon

Location 
            Suez Canal        Earth

Time
             Earlier this week


The Suez Canal is now reopened for business thanks, in measure, to the Sun and moon!    Many subscribers contacted me about this story and urged me to devote an article to it.   Hence, well, this article.

Let's proceed to the satellite view:


suezships.jpg

The left image, captured earlier in March, shows the procession of ships lining up to proceed down the Suez Canal, a human-made waterway connecting the Red and Mediterranean Seas.    The right image shows a veritable swarm of ships clustered in the Gulf of Suez.   A large cargo ship became lodged in the canal which prevented the passage of numerous vessels that transport goods through the waterway. It is estimated that approximately 12% of global trade passes through the canal.

On March 23, the Ever Given, a gargantuan Taiwanese cargo vessel traveling between Malaysia and the Netherlands ran aground in the Suez Canal in such a way as to obstruct it entirely.  No vessel was able to move through the canal until March 29, 2021,  Throughout that week, many salvage crews attempted to dislodge the Ever Given by removing sediment around it and nudging it with a series of tugboats.  Finally, early on March 29th, all of the ship except for the bow was refloated.  Soon after, the bow was liberated and the Ever Given was free.

Engineers attribute their success in part to the Super Moon.   We recall that the Super Moon occurs when the moon is full around the time it is at or near perigee, its closest point to Earth in a given orbit.      Not only is the super moon larger and brighter than other full moons, the tides that occur during a super moon are also higher.

First, we need to define two types of tides:

  • SPRING TIDES: tides that occur when the moon is either new or full. At those times, the moon and Sun are aligned so as to render the high tides higher than usual.   
  • NEAP TIDES:  tides that occur when the moon is either at first or last quarter. At those phases, the moon and Sun are at right angles, which causes the high tides to be lower than usual.   The Sun's contribution to the tides is 44% that of the moon, so their tidal effects are muted when they are perpendicular to each other relative to Earth.

When the moon is full or new when at or near perigee, Earth experiences Perigean Spring Tides:  the spring tides are even higher than usual due to the closer proximity of the moon.
The moon's distance affects tides considerably since differential gravitational effects are proportional to the cube of the distance, as opposed to such the square of the distance. 
 
perigean-spring-tide-new-full-NOAA-e1388335934325.jpg

The Perigean Spring Tides that occurred earlier this week raised the Suze Canal waters about a foot and a half higher than usual during the high tides.  That increase helped the engineers to refloat the boat and open the Suez Canal.       Although economists aren't quite sure how much damage this situation inflicted to the global economy, especially since it's taken a five-fisted beating within the last year already, we can cheerfully report that global trade in the Suez Canal is open again.

Well done, Artemis...

985753fa0a9ddee267202dd70df298df.jpg



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