Bow-Tie Nebula (Credit:NASA)
Located 5000 light years from us, this young planetary nebula called the Bow-Tie Nebula or Boomerang Nebula is till now the coldest place ever detected in the universe. It is just one degree warmer than the lowest limit of temperature possible – the absolute zero (-273C). Even the background radiation i.e. the glow of big bang is warmer than this nebula.
This beautiful shape of the nebula can be credited to the central star which is in its last stages of life and is expelling gas in tremendous force hence making these delicate structures in space. The light in this image is basically starlight being reflected by dust particles clicked using a green-yellow filter.
I have always loved Italy more than Switzerland till I got a chance to visit the Mt Titlis – the highest destination peak in Central Switzerland. This is the place where many scenes of my favorite movie DDLJ was shot. We drove from Austria to the small place surrounded by the Alps in Switzerland, from where we had to take a cable car for a Journey of 45 minutes to climb up an altitude of 3020m. This post is just to share few photographs I clicked from this cable car.
The first half-an-hour of the journey was in a small cable car cabin for maximum 6 people. We first saw small cottages below with vast green fields where cows with bells on their neck were grazing, making a soothening synchronised bell sound that would make the whole atmosphere more magical. As we moved up, the fields were gone and we found ourselves on top of a bunch of dark green dense trees through which the land below could not be seen at all.
The Trees and the M0untains
The new nebula in my list of favorites – The Calabash Nebula – known commonly as The Rotten Egg Nebulae not because it resembles one but because it smells like one – :p well, at least that is what we expect due to the unexpectedly large amount of Sulfur in it!
Calabash Nebula (credit: NASA)
This is a proto-planetary nebula (PPN) located ~ 5000 light years from us, surrounding a cool and dying star. It is a field of violent gas collisions resulting in supersonic shock fronts. Material ejected from the central star are accelerated in opposite directions which form the densest regions in the nebula (seen as yellow). The dusty part at the center of this bipolar structure is hiding the dying star which is creating this beautiful structure in space!
Yesterday my sister pointed out that I have written about Paris, Rome, Kassel, Salzburg and many other places but have not really posted annything about my current address – Göttingen! Well, it is not a place with grand heritage buildings and some magnificent monuments and beautiful lakes and lovely parks. But it is a special unique city – mainly because of it’s vibrant young population conmprising of people from all over the globe.
The Physics Department Garden
Göttingen is truely termed as the City Of Universities. Everywhere you go, you end up being with a bunch of students. Amazing it is. This is like the much bigger version of the North Campus of Delhi. The Georg-August-University boosts of 25,000 students from different parts of the world, a huge impressive library with 5.8 million volumes, 48 nobel prizes in the last Century and an alumni list with people like Otto Hahn and Max Born (founders of Quantum Theory), A. Windaus (discoverer of Vitamin D), Minkowski and Hilbert (laiding fundation of Einstein’s Theory of Relativity), the brilliant Mathematician and Astronomer Gauss and many more international scholars.
This is interesting to learn how from an ‘almost’ homogeneous space with a very few tiny density perturbations; these big galaxies, stars, planets were made – how these first ever structures were formed. But it is tough to study that, specially because we can not observe the ‘first-ever stars’ being formed and theoretically too it’s a bit tricky – you need to take care of loads of physics and on paper it goes all messy. But we have another option – and that is to simulate the universe using numerical computations (we know how it was after inflation, we know how it looks like now, we know the forces that should be influencing the formation of structures in space, so it’s not that tough)!!
Presenting here are few snapshots of a simulation I have been running for the final project of my lab course on Numerical Simulations. This is using a cosmological code called ENZO and the following eight slices are focussing on a single region in space as time flows (from ‘then’ to ‘now’). The three sub-plots on each of these slices show the density, temperature and velocity of the matter at that point of time. The first slice was made when the universe was very young.. and as you go down the slices, you see more and more modern version of the universe, the final slice being the universe now.
I have been told many a times – ‘Once a Stephanian is always a Stephanian. The word Ex-Stephanian does not exist.’ Waiting in Roma Railway Station for Raghav and Jayant (my Stephanian classmates who are studying Nanoscience in Paris) and Rajarshi (another batchmate of ours from Maths department), I had my chance to experience for myself how much alive the Stephanian Spirit and Bonding is within us.
I still remember the train entering the station and the feel of spotting the smiling familiar faces among those numerous strangers. It was as if everything has always been the same, we had Phookun’s class yesterday and this is just another day-out we are having – the one year gap vanished in seconds! We roamed together, enjoyed Italian Gelato, walked through the historic streets of a lovely Rome, hogged on typical Indian food in a Restaurant with old bollywood songs being played in the TV, shared our exotic experiences laughing at the weirdest cultural shocks, got mesmerised by the beauty of the Colosseum, had the SRK-BigB debate in the Spanish Steps, made wishes in the Fontana di Trevi and fondly remembered those days in Stephen’s!!
The best part of the whole tour for me was the night walk that we had in the deserted streets of Rome – this place somehow gets even prettier at night – the perfect beauty!! Here are few pictures clicked on that day –
In front of Fontana Di Trevi - Evening!
The Earth rotates around it’s own axis. One of the most amazing consequence of this motion is that the sky appears to move around in circle on the celestial sphere – an effect termed as Diurnal Motion which makes the stars to trace concentric circles on the sky once a day. The stars appear to rotate around either the North or the South pole. This motion can be tracked with a time-lapse photograph – using a normal camera with high exposure time – and the result is the amazing artistic picture as shown above. Continue reading