Twinkle Twinkle little star

Part – 2: What connects humans on earth to far far away stars and galaxies is ubiquitous Photon.

In our daily life we all admire the high speed of Bullet trains and Supersonic Jets. However this reduces to nothing more than that of a bullock cart when we compare it with the velocity at which light and infact whole of electromagnetic waves move which is c, 3 lakh kilometres per second which is the fastest speed any object having mass can ever achieve.

A light beam is made up of particles called Photons, messenger of God which brings information to us from all over the universe. ‘c’ is one of the many Universal constant which defines the structure and fabric of space time of the universe. Other important such constant being h (Planck’s Constant), e(electronic charge), G( gravitational constant) etc. No object having mass can move faster, even come close to photons speed as Photon being a zero rest mass particle. Photons brings us information from stars born billions of years ago, from the start of Universe, the Big Bang moment. A light year which is the distance light travels in one year is taken to be a common unit of distance in Astronomy.

It is of utmost importance to realize that the vastness of universe and that it was born billions of year ago with a big bang is not an imagination of some fertile mind like a poetry is. It is based on hard experimental evidences that astronomers have painfully gathered by observations. Lets us present two such evidences. According to NASA Wilkinson microwave an isotropy probe released in February 2003 show that the first Star is formed about 200 million years later of the formation of universe. It is remarkable that Harvard scientist have been able to detect the first evidence of gravitational ripple which was sent out in the first second of the so called Big Bang.

Sadly, in India astronomy is not given the importance it deserves as most think that it is not lucrative career option. Still more unfortunate is we spend so much time money and effort in study of palmistry and astrology which do not have any scientific basis.

There are only two outstanding names that come to our mind in the area of astrophysics, one is ‘S.Chandrasekhar’ an astrophysicist who won Nobel Prize in 1983 and the other is ‘Jayant Narlikar’ student of astronomer professor ‘Fred Hoyle’.

On an astronomical scale the members of Solar family like the moon, Mars, the planets of Solar family just like your next neighbors. In that sense whom you can visit either now or in near future. It takes light a fraction of second to arrive from Moon, 8 minutes to arrive from Sun.

Although, the large bodies orbiting our Sun that is planets and their moon like Jupiter Mars Saturn etc but also the small bodies like asteroids comets and metroids that fill in the space between these planets is equally interesting, because they carry much information about the origin of our solar system. Apart from Star that is sun, the head of the family there are 8 planets tens of moons, some dwarf planets. Another interesting thing in solar system is Kuiper belt which contains many fragments of solar system.

In astronomy we focus on stellar objects which are away light years and beyond. The nearest star is alpha centauri which is 4.37 light-years from the Sun. The nearest galaxy to our own Milky Way galaxy is ‘Andromeda’ and is 2.5 million light year of distance away. It is interesting to note that the farthest star ever observed by Hubble Telescope is named ‘icarus’ which is 5 billion light years away. There is no way we could ever imagine even in future to physically visit them. Even if we imagine a photon in a science fiction movies gains consciousness of a human that will take billions of years for round trip and in all probability by the time humans traveller returns there will be no civilization left on the earth to greet him. Since the human civilization is expected to exists only for about 20 thousand year.

Astronomy is science of stars and galaxies that are millions of light years away. There is no way we can study them the way we have been studying our planet Earth. Geology is the science of rocks and soil on earth, oceanography is about the nature of oceans but to get the same level of details about stars and their planets is an enormously difficult task.

The only comfort that we have is that not only laws of Physics are same but the atoms and the light and the whole electromagnetic spectrum that put in other words matter and radiation is same throughout the entire universe. Ofcourse there are exotic states of matter in stars like supernova red Giants and white dwarf is quite strange to say the least. But the only way to gather information from these distant objects is through the type and intensity of spectrum they emit. In some way we are talking about atomic physics, Spectroscopy which are well established area. How to carry out Spectroscopy of objects millions of light years away from us?. That is the million dollar question.

As a first step towards understanding and appreciating astronomy we need to grasp the basic nature of electromagnetic spectrum, the experimental techniques for the study of emission and absorption spectroscopy. In the next article we will introduce these topics.