Travertine Written by Joey Lewitin
Travertine is one of most beautiful, versatile, and historically important stones. Its durability makes it highly useful in building applications, and it has been used in this manner since Roman Empire.
Formation Travertine is a form of limestone that is heavily compacted. Generally it is formed when minerals in streams or hot spring water become deposited on river beds and dry out. If chemical composition has enough of mineral calcium carbonate in it, then result is considered to be travertine.
Coloration In its purest form travertine is a very pale color, however imperfections in its structural make up, such as presence of iron, can cause beautifully colorful banding to occur across its face. Different colors are caused by different minerals, and different shapes are formed in stone dependant on how impurity combines with its structure. Since imperfections show up semi-randomly, no two pieces ever look exactly alike. It is however grouped into quarry names where similar strains of marble taken from similar places are classified into categories.
Time travel: sci-fi?Written by Khalil A. Cassimally
When you look at clear night sky, you see stars-those tiny diamonds suspended in vast pitch-black emptiness. But stars shine because…? Our own sun, which is a star, emits light. Stars are like giant bulbs but are much more powerful.
Light travels at a speed of 3.0*108m/s in vacuum and space is mostly vacuum. In other words light can cover a mighty distance of 300 000 000m in only 1 second!
The thing is that 300 000 000m is a just one of those small amounts in space. Other stars are billions of kilometres-let alone metres-away. Astronomers in fact use light year as unit for distance. One light year is distance travelled by light (in vacuum) during one year. Therefore one light year equals (300 000 000*3600*24*365)m.
A single light year is definitely huge: 9.46 trillion kilometres-no need to put this in digit form-in fact. But where exactly do I want to converge? A star that you see in night sky is not one but many light years away. This means that it is very far away. But most importantly, it means that light from this particular star takes many years-and not mere seconds-to reach your eyes! So what?