Saturday, April 20, 2019

Iceberg fact file




An iceberg is a large piece of ice that has broken away from a glacier or ice shelf. Icebergs in the North Atlantic mostly come from glaciers on Greenland, and those in the South Atlantic from the Antartic.



  • The word icebergs probably come from the Dutch ijsberg or ice hill.
  • Icebergs float because they are made of fresh water which is less dense than seawater.
  • Seven-eights of an iceberg is below the surface of the sea, hence the expression "the tip of the iceberg", which means that more is concealed than can be seen.
  • The tallest iceberg ever measured was 168m high. It was seen in 1958 off Greenland and was as tall as a 50 - story skyscraper.
  •  Small icebergs are known as Growlers, because of the noise they make.
  • Icebergs larger than growlers(1metre+) are called bergy bits; then they are graded small, medium, large or very large. Very large icebergs are those measuring more than 75m high and 213m wide.
  • One of the biggest icebergs of recent times, known as B-15, broke away from the  Ross Ice Shelf, Antartica, in March 2000. It had an average length of 295km and width of 37km, giving it a total area of about the size of Jamaica!
  • The air trapped in iceberg ice - which is "harvested" and sold for use in drinks - may be as much as 3,000 years old.
  • At least 500 incidents have been recorded of ships striking icebergs. In 1875, the 82 crew members of the schooner Caledonia were rescued after their ship sank they spent a night sitting on an iceberg. The worst - ever disaster involving an iceberg happened when the Titanic struck an iceberg on 14 April 1912 and 1,503 lives lost their lives.
  • During WW2, Lord Mountbatten led a program devised by British inventor Geoffrey Pyke to build artificial icebergs to use as aircraft carriers, but the project, codenamed Habbakuk, was abandoned.
  • About 10,000 to 15,000 new icebergs are formed every year. The process is called "Calving".

Thursday, April 18, 2019

Star Facts


A star may be a bright body of gas, mostly hydrogen and helium. Stars generate light, which makes it possible for us to see them with a telescope or the naked eye. They conjointly unharness energy from fission reactions in their core.


Brightest

Sirius

Not numerating the Sun, the brightest star as seen from Earth is Sirius, known as the dog or binary star, in the constellation of Canis Major. It has a diameter of 149,598,020km and is over twenty-four times brighter than the Sun. The star Cygnus OB2 No 12, discovered in 1992, is so far away that it can't be seen from the planet Earth. It may be the brightest star in the Galaxy - up to six million times as bright as our Sun.



Heaviest
HDE 269810


HDE 269810 is a star in the Large Magellanic Cloud - 170,000 light years from Earth. It's been discovered by the Hopkins Ultraviolet Telescope to be one hundred ninety times as heavy as our Sun.


Largest

Betelgeuse

The largest star is the M-class supergiant Betelgeuse or Alpha Orionis. It is the highest left star within the constellation of Orion, which is 310 light years away. It has a diameter of 700million km, which is about 500 times greater than that of the Sun.


Nearest

Proxima Centauri

Proxima Centauri, discovered in 1915, is 4.22 light-years from Earth. A space vehicle moving at 40,000km/h - which is quicker than any human has yet traveled in space - would take more than 114,000 years to reach it.


Supernovae

Supernovae

These are large explosions during which a whole star is blown up. They're extraordinarily bright, rivaling for a few days the combined light output of all the stars within the galaxy. Supernovae are rare - the last one in our galaxy was seen in 1604 by the German astronomer Johannes Kepler.



Quasars

Quasar



Quasars are extremely distant radio galaxies - galaxies giving out an outsized quantity of radio energy - and the brightest objects in the Universe. Even those close to the foremost distant fringe of the noticeable Universe are simply detected by small radio telescopes. Their radio emission is typically 1,000,000 to 100,000,000 times greater than that of a traditional galaxy, and they are as bright as or brighter than the brightest radio galaxies.


Black Holes 

Black Hole


A black hole is a star that has collapsed into itself. It has a surface gravity so powerful that nothing will escape from it.