The Hellenic Navy (HN) (Greek: Πολεμικό Ναυτικό, Polemikó Naftikó, abbreviated ΠΝ) is the naval force of Greece, part of the Greek Armed Forces. The modern Greek navy has its roots in the naval forces of various Aegean Islands, which fought in the Greek War of Independence. During the periods of monarchy (1833–1924 and 1936–1973) it was known as the Royal Navy (Βασιλικόν Ναυτικόν, Vasilikón Naftikón, abbreviated ΒΝ).The total displacement of all the navy's vessels is approximately 150,000 tons.The motto of the Hellenic Navy is "Μέγα το της Θαλάσσης Κράτος" from Thucydides' account of Pericles' oration on the eve of the Peloponnesian War. This has been roughly translated as "Great is the country that controls the sea". The Hellenic Navy's emblem consists of an anchor in front of a crossed Christian cross and trident, with the cross symbolizing Greek Orthodoxy, and the trident symbolizing Poseidon, the god of the sea in Greek mythology. Pericles' words are written across the top of the emblem. "The navy, as it represents a necessary weapon for Greece, should only be created for war and aim to victory."...............The Hellenic Merchant Marine refers to the Merchant Marine of Greece, engaged in commerce and transportation of goods and services universally. It consists of the merchant vessels owned by Greek civilians, flying either the Greek flag or a flag of convenience. Greece is a maritime nation by tradition, as shipping is arguably the oldest form of occupation of the Greeks and a key element of Greek economic activity since the ancient times. Nowadays, Greece has the largest merchant fleet in the world, which is the second largest contributor to the national economy after tourism and forms the backbone of world shipping. The Greek fleet flies a variety of flags, however some Greek shipowners gradually return to Greece following the changes to the legislative framework governing their operations and the improvement of infrastructure.Blogger Tips and Tricks
This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς....This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς.........

Tuesday, February 21, 2012

Moon geologically active...[ 2727 ]


Moon still geologically active


Posted on February 21, 2012 - 04:18 by Kate Taylor//TG DAILY

There's still some geological activity on the moon, new images from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft show.

 =
The moon's crust is being stretched, forming minute valleys in a few small areas on the lunar surface. And the team believes they were created less than 50 million years ago - pretty recent compared to the moon's age of more than 4.5 billion years.
The images show small, narrow trenches, mostly much longer than they are wide, known as graben. Such valleys form when the crust stretches, breaks and drops down along two bounding faults. 
-
"We think the moon is in a general state of global contraction because of cooling of a still hot interior," says Thomas Watters of the Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum in Washington.
-
"The graben tell us forces acting to shrink the moon were overcome in places by forces acting to pull it apart. This means the contractional forces shrinking the moon cannot be large, or the small graben might never form."
The weak contraction suggests that the moon, unlike the terrestrial planets, didn't completely melt in the very early stages of its evolution. Instead, it looks as if initially only the moon's exterior melted, forming an ocean of molten rock.
-
Scientists are scratching their heads somewhat over the images, however.
In August 2010, the team spotted signs of contraction on the lunar surface, in the form of lobe-shaped cliffs known as lobate scarps - evidence that the moon shrank globally in the geologically recent past, and might still be shrinking today. 
-
The team concluded the moon was shrinking as the interior slowly cooled - while the graben indicate, in contradiction, that regions of the lunar crust are also being pulled apart.
"It was a big surprise when I spotted graben in the far side highlands," says Mark Robinson of the School of Earth and Space Exploration at Arizona State University.
-
"I immediately targeted the area for high-resolution stereo images so we could create a three-dimensional view of the graben. It's exciting when you discover something totally unexpected and only about half the lunar surface has been imaged in high resolution. There is much more of the moon to be explored."
- 

Αναρτήθηκε από στις
Ετικέτες

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)