WHERE we are now is the border line between astronomy and astro-physics. At many places the dividing line is quite blurred — though it doesn’t matter much! Because, in a way they are, sort of, twins. However, we discussed many details common to both of them.

It was an amusing journey acquainting ourselves, especially myself, with many new items. Quite a rewarding journey too! The language of astronomy is the same as the language of astro-physics. One language that will apply to both sciences! But astrology distracts you from reality, pitches you into the world of make-belief, and what not.

My idea is to bring home to you, my young friends, the total implication (meaning) of astronomy, and science, at your doorstep. One of the first ways is to understand the basics: what do all those wonderful, and often romantic words mean after all?

For instance, the word ‘albedo’? Unless and until you know what the word really means it will be lost on you in a jiffy. Hence my effort to, I daresay, educate you to that extent. First the astronomical parlance in continuation to the material contained in the last issue:

Acid rain

ALTHOUGH not related to astronomy directly, acid rain is a common feature on Earth, as well as some other planets. The term includes all kinds of precipitation (snow, rain or sleet) whose acidity exceeds the normal (pH 5.6). On the pH scale, the lower the number, the more acidic the substance. Rain is made unnaturally acidic by emission, or infusion of sulphur dioxide and nitrogen oxides from the burning of fossilised fuel, mainly coal.

Acid rain does not appear to be harmful to us humans, but when it falls into lakes and rivers, it acidified them enough to kill the hapless fish and other aquatic life. It also damages trees and some crops. Worse still, the acidity levels are worsening each year and some sort of corrective action, however costly, will eventually have to be taken to stall the increasing damage. Either we take the corrective action now, or suffer the consequences later.

Alpha Centaurii

IT is a triple star system including the star Proxima Centaurii — the nearest star to the Solar System. Light takes 4.3 years to reach us travelling at 300,000 km per second. At the present time, the fastest rocket would take 120,000 years to reach near Alpha Centaurii.

An average observer can see about 6,000 stars in the sky. Alpha Centaurii is located low in the southern sky and not visible to observers in the Northern latitudes. In our skies (north or south) it is about the third brightest star. Just imagine three stars circling around each other!

Alpha particle: A positively charged composite particle, it is indistinguishable from a helium atom nucleus and comprising two protons and two neutrons. It is one of three types of radioactive emissions (the others are beta particles and gamma rays). A stream of alpha particles is called alpha rays or alpha radiation. About beta particles, neutrons or protons, and many other such items, let us wait for their turn!

Amino acids: Organic acids that are the building blocks from which proteins are constructed, or manufactured. There are 20 common types of amino acids and the properties of every protein depends on exactly how, and in what order, these amino acids are arranged in the molecular chain. Protein molecules are long, usually folded chains made up of 20 different kinds of aminos and molecules. The functions of each protein depends both on its sequence of amino acids and the shape the chain takes.

Andromeda Galaxy: A large pin-wheel Galaxy much like our own, the Milky Way, but much larger. Like us, it is a system of stars held in place by the massive internal gravity. It is one of the billions upon billions of galaxies in the universe which together make up the universe. It is 2.2 million light-years (l.y) from us. At this point in time, Andromeda Galaxy is gently approaching towards us. But it is not likely to collide with ours — not even in the next one hundred million years. It will then veer away, bypassing us, still staying many trillion miles from us but enough to disturb our equilibrium, very specially the outer portions of our galaxy, where we are located. Those who will be around then will be feasted to galactic fireworks every night for as long as a billion years.

Andromeda commands a large group of galaxies like the Milky Way, the Large and Small Magellanic Clouds and some other galaxies. Together they are called, the Local Group. All these galaxies are subservient to Andromeda. This beautiful Galaxy is visible to the naked eye on any night, but looks particularly impressive on wintery night. Located in the constellation of the same name, it is situated not far from the Pole Star. So it can be said to be circum-polar, though it still shifts its position in the sky just a little bit.

Enough for a day’s work for my young friends, I suppose. Look after yourselves. Goodbye, till we meet in the next issue.