The Universe in a year

The American astronomer Carl Sagan who lived during the period of 1934-96 was the first person who suggested a “cosmic calendar” as a way of helping people to understand the history of the Universe. He placed everything into the scale of a calendar year; the galaxies are formed over nine months and the Earth appears in September. All human history is crowded into the last five minutes of the last day of the year. Recent time has to be divided into seconds and fractions of a second. So everything that happened over the last 475 years place in less than the last second of the last minute of the year.

Extremes of the World

Longest River

Africa’s Nile River is the world’s longest. It is 6,695 kilometers long. It flows through nine countries. The White Nile and the Blue Nile are its two main tributaries. The White Nile starts from Lake Victoria in Uganda, and flows through Sudan and Egypt. The Blue Nile starts in Lake Tana in Ethiopia and flows through Zaire, Kenya, Rwanda, Tanzania and Burundi. The two tributaries of the Nile merge at Khartoum, the capital of Sudan.

Largest Desert

The Sahara is the largest desert on Earth, Located in North Africa and spread across 11 countries; it covers an area of 9 million square kilometers. In terms of area it is as large as the continent of Europe. In 1922, the temperature reached 57.8 degree centigrade makes it the highest recorded temperature on Earth. It might sound strange, but the peaks in the desert are snowcapped during winter.

Largest Island

Greenland, a self – governing province of Denmark is the largest island in the world, located between the North Atlantic and the Arctic Oceans, 85% of it is covered by ice. July is the only month in which the temperature goes above freezing point. The sun never sets in Greenland during the Arctic summer, since it is very close to the North Pole.

Highest Peak

Mount Everest is the highest mountain peak in the world. The Everest is just one of over 30 peaks in the Himalayas, Located on the border of Tibet and Nepal, it measures 29,035 ft in height above sea level. Sir Edmund Hillary and Tenzing Norgay were the first to conquer Everest, on May 19, 1953. The Everest is also known as Sagarmatha in Nepali and Chomolungma in Tibetan. It is believed to grow anout 4 mm every year due to geological forces.

Coldest Place

Antarctica is the driest windiest and coldest place in Earth. It is the fifth largest continent and is the only land on our planet that is not owned by any country. It reached a record -89.2 degree centigrade making it thr coldest temperature measured on Earth. Strange through it may sound, however, Antarctica is the largest desert in the world. The average annual rainfall is as low as 20 millimeters.

Do you know the Tricks of Fish

Ever wondered how a stationary fish sometimes sinks to the bottom and then rises to the surfaces? The reason behind it can be attributed to two forces of Nature gravity and buoyancy. Gravity is the force that pulls objects to the ground while buoyancy pushes them up in water. Gravity depends on mass while buoyancy depends on volume. So, how does the fish remain at one place if it has to, without being affected by those forces?

The fish is endowed with an organ called the swim bladder. The swim bladder is like an empty balloon. When the fish breathes, the bladder is filled with oxygen. So, the fish expands in volume but its weight does not increase much. So, this increases its buoyancy. When the fish exhales, the bladder loses the oxygen and shrinks in volume. Thus, the decrease in volume increases the force of gravity on the fish.

When the fish has to stay at one place, it breathes in a sufficient amount of oxygen. This slight increase in volume has the same weight as that of the fish. The two opposite forces are cancelled, and thus the fish remains stationary.