Ghosts of the Past
It’s often said that don’t look back , which means don’t look into your past and focus on your future, well it might be philosophically correct but but factually if you want to look into your past, don’t look back, LOOK UP ,yeah up in the sky.
So the basic principle of vision is that when a ray of light emitted or reflected from a surface falls on our eyes , we are able to see it. The stars you see in the night sky are Light years away from us, which means the ray of light which originated from them years ago, is reaching us now, they might not be there at this point of time, so basically we are looking into the past thousands of years.
But there is another saying , know your past to realise your current standing, this holds true both philosophically and factually. There are two units of measurement in the world, Space and Time. Let’s see what is our position in both.
Space, the standard unit of distance for universe in Light year and for us humans its Kilo meter or. miles. Do you know 1 Light year is equivalent to 9 Trillion kilometres.Now Time, universe is estimated to be 13.8 Billion Years old and its life time can’t be comprehend, and for humans our life span is max. Hundred years. And we all know 1 billion years is 10,000,000,00 years.
It may sound metaphorical to some and anecdotal to others, but to prepare for our future we need to look deep into our past. For this reason NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA) came together , worked tirelessly for more then three decades and spent over $10 billions to make worlds most advanced and powerful space telescope, James Webb Space Telescope (JWST)
JWST is named after James Edwin Webb, the NASA chief at the time of moon landing. It is an Infrared telescope , i.e. the visual range below colour red which is not visible to human eyes. Its primary mirror is about 21.3 feet wide and is plated with 24 carat gold, which enables its to reflect 98% of the light falling on it. It was launched on 25th December 2021 and reached its orbit covering a distance of 1.5 million kilometres over a period of one month on 24th January 2022. JWST will replace the existing Hubble telescope.
You must be thinking why the telescope is placed in space when we can install far bigger telescope on land, Its because of the atmosphere , the gases and other content in our atmosphere interferes with the electromagnetic rays coming from outer space and distorts them. Now its not placed anywhere in the space, there is a very specific location called Lagrangian point (L2). L2 is a special location where any object (JWST in this case) is shielded form direct sun by earth and moon which enable it to look deep into space.
JWST’s mission is to search for the first formed galaxies, formation of stars, locating planets and exo-planets and potential life supporting celestial bodies. Some of these you will see in the first released pictures.
Now lets understand what’s so special about it? As already stated , its an infrared telescope with large mirror, it has the capability to look into the space as far back as the origin of universe i.e. 13.8 billion light years away. And also locate cold and far away planets which were previously not visible. It will be able to see the nebulas and nurseries where stars are formed from gases , dust and other start materials of dying star.
Life span of JWST is estimated to be 5.5 to 10 years, this is because there is a limiting factor.
The telescope is orbiting at an altitude of 1.5 million k.m. with the help of a propellant called hydrazine fuel. This is needed to maintain the telescope in its orbit. Due to its limited supply, JWST will eventually run out of this fuel and come back falling due to earth’s gravitational pull.
Now let’s see some of the images from the first batch of JWST. But before watching the pictures please know that that these are not images clicked or snapped in a fraction of second like DSLRs and mobile cameras, its a set of data (images) collected over a period or time ranging from few hours to several days, using different filters for same image and then collaborating them into a single picture.
- SMACS 0723
It’s the deepest and sharpest image of the universe ever taken. Here every dot is either a star or a galaxy. The once which are looking like red brush strokes are actually so far away that the light coming from them got bent by the gravitational force of other galaxies. This is called Gravitational lensing. There is a dull red spot at the centre left of image. It’s the galaxy that is 13.1 billion lights years away. The deepest spot. To contextualise the size of universe this image is equivalent to a sand grain.
2. Carina Nebula
This one is my favourite and the most beautiful of the lot. Its a nursery where stars are born. It is an active cloud of dust and ionised gases continuously giving birth of new starts. Every dot is a baby start in its early stage of life. Its about 7500 light years away and the with of image extends till 16 light years.
3. Southern Ring Nebula
It the the cloud of gas and dust thrown away by a dying red gaint (start) located at the centre. If you look at the image on your right, you will se there are two stars , the smaller one is the white dwarf (red giants become white dwarf after their death) which is dying and throwing this cloud, the other is the brighter twinkling one which is at its early stage of life.
4. Stephen’s Quintet
It is a group of five closely bounded galaxies (quint refers to five) some 300 million light years away. We can see only four spiral shapes as the one to the right is a couple which is in the process of merging.Ultimately all five will collapse into each other. It’s a compilation of 1000 images and total of 150 million pixels.