The Esmeralda is one of the largest tall ships to sail the world’s oceans.
She is a Spanish manufactured steel-hulled four-masted barquentine (manufactured and delivered as a schooner) taken into service in 1953.
She is used as a training ship of the Chilean Navy and act as a type of floating embassy for Chile.
In spite of her impressive size and a claim during her service to be in podium position for both longest and tallest ocean going sailing ship, she has been surpassed several times by even larger tall ships.
The largest square rigged ocean going tall ship is currently the 5 masted clipper ship the Royal Clipper, with 5202 square metres of sail, launched as recently as the year 2000.
The Cango caves natural monument near Oudtshoorn in the Eastern Cape province of South Africa is one of the first natural resources to receive protection in South Africa. The first Caves Regulation was published in 1820 banning the collection of souvenirs and fines for damaging the caves.
How large the cave complex is is still unknown, but what is known is that it exceeds 5 kilometers in length. The single largest chamber in the complex is 107 meters across and 16 meters high.
Legend has it that Chinese alchemist mixed saltpeter (or potassium nitrate) with sulfur and charcoal to form crude gunpowder
sometime between 600 and 900 C.E. while searching for an
elixir for immortality.
Gunpowder was used in fireworks prior to being used in weapons.
The colours in fireworks is due to burning metals. Elements burn at different light frequencies (wavelengths) and different mixes of metals result in different fireworks colours:
deep reds from strontium and lithium
blues from copper
silver / white from titanium and magnesium
orange from calcium
yellow from sodium
green from barium; and
neon green and turquoise from combining barium or copper with chlorine
The moon is in synchronous rotation with the earth. This means that the moon turns around its own axis at the same speed it orbits earth. The result is that the same side of the moon is always visible from earth.
Due to irregularities in the moon’s orbit, slightly different portions of the moon is visible at different times, but no more than 59% of the moon’s surface can ever be observed from earth.