LIFE is complicated, and getting more so by the hour. One aspect of this is that Science and technology have left the lab and are no longer the sole concerns of scientists and engineers. These fields of thought and actions are part of every one of our lives. Whatever our occupation, or, wherever in the world we live. — James Rutherford.

FOR too long and too far we strayed around the most perplexing objects of Mother Nature called Quasars. Now I want you to relax a little and learn something new and very interesting. This will launch you into new realms of the science called astronomy.

I have been meaning to show you around the special world of astronomy (in astronomical parlance) without which astronomy is not fully understood. Every branch of science, or learning has words peculiar to it, called its idiom. The same of course is true for astronomy where some words have been taken from English language no doubt but their implications are somewhat different from that commonly implied in spoken English. We shall see how.

For your convenience I propose to proceed alphabetically. These words are commonly used in astronomy. Common but vital and important. For you to understand astronomy, it is absolutely essential that you get a hang of these terms. Here we go!

Albedo: Albedo is the amount of light reflected by an astronomical body after some of it (light, that is) has been retained, or absorbed by the body. Remember that albedo cannot be greater than what has been supplied to it by a luminous body.

For instance, let us take the Sun throwing light on the Earth. The Earth receives this light but (after absorption) when the Earth reflects light back into space, or, whatever light is visible after absorption is less than the light received by it. That amount is the Earth’s albedo. The maximum possible albedo is 1, and the minimum, when no light is reflected at all, is 0.

Albedo plays a major role in climate change. Ice covers just about 10 per cent of Earth’s land area. It reflects more light than bare rock or soil. Ice reflects 90 per cent of the light that falls upon it. Bare soil reflects less than 10 per cent. A slight increase in ice cover would mean more sunlight would be reflected and less absorbed, resulting in drop in average temperature on the Earth. That would be catastrophic for life on Earth. It would be catastrophic for life if the contrary happened. This makes the study of albedo an important factor in long term climate changes.

It is believed that 65 million years ago when a large comet or an asteroid, hit the Earth and it kicked up a huge amount of dust, resulting in blockage of sunlight. That resulted in an unusually long winter, lasting many many years. In such extra-ordinary conditions the albedo dropped, and for sometime it must have been zero.

A new ice age enveloped around the planet then that wiped out much of life forms. Once that happens it takes millions of years for life to proliferate (develop and spread as before).

Absolute zero: It is theoretically the lowest possible temperature. At this temperature substances possess no energy at all. Generally stated as “Zero Kelvin”, absolute zero is equal to about -273C, or -460F. All bodies, whether in gas, liquid or solid forms, are collections of molecules, and temperature affects the velocity of these molecules. That is, atoms move fast or slow down according to the heat applied to them. The higher the temperature, the faster they move and the more volume they require (i.e they expand). The lower the temperature, the more slowly they move the less volume is required (i.e they contract).

As temperature decreases, the molecules (or atoms) possess too little energy to move at all. In other words, the substance is frozen solid. Although scientists have come within a millionth of a degree, absolute zero is absolutely unattainable. The struggle to know why substances or material behave oddly at about absolute zero is called Cryogenics. Temperatures of all bodies, whether stars or planets, or lesser bodies, indicates much more about them than just the temperature. That is why it is necessary for us to understand all about absolute zero, and higher temperatures.