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Showing posts from June, 2015

X-ray astronomy : The instruments behind the science

If you follow science news regularly, you will come across news of the kind "Astronomers find brightest object of the early universe" or "Black hole-powered jets plow into galaxy". I would just like to point out that when they mean "brightest" object, they don't mean that it's the brightest object in the visible part of the electromagnetic (EM) spectrum. They mean that it's the brightest object in terms of energy emitted across the EM spectrum i.e X-ray, UV, visible, IR and microwave radiation all put together. (And just to throw in a bit of jargon, an object's brightness is quantified in terms of it's luminosity and the luminosity of an object measured across the EM spectrum is referred to as the "Bolometric" luminosity.)

Coming to the specific cases mentioned above, the quasars are in fact brightest in the X-ray, UV regime of the EM spectrum and astronomers use X-ray telescopes to look at them! At this point, I would like …

Beyond the standard Hot big bang model

“Our whole universe was in a hot dense state,
Then nearly fourteen billion years ago expansion started. Wait …
That all started with the big bang (Bang)!”is how the theme song of the popular TV show “The Big Bang Theory” starts.” “Since the dawn of man” is really not that long,
As every galaxy was formed in less time than it takes to sing this song.
A fraction of a second and the elements were made …
Set in motion by the same big bang!”“It’s expanding ever outward but one day
It will pause and start to go the other way.
Collapsing ever inward, we won’t be here, it won’t be heard
Our best and brightest figure that it’ll make an even bigger bang!”Well, for all intents and purposes, that’s a pretty good introduction to what the postulates of the standard Hot big bang model are. That the universe started from a hot dense state and that it started expanding outwards. As it expanded, the temperature started to cool down. After a certain point matter and radiation, which were previou…

Weeds and Invasive species

Me and a friend of mine (an ecologist in training) were talking about weeds (plants) and i asked her about the advantages they have over natives that lets them thrive. She mentioned the fact that they might be alien species, transported to a new location devoid of their natural predators, therefore giving them the advantage to grow faster than the native species. There might also be other genetic variations which help the weeds. And given that weeds, by definition, can pop up at most places on earth and are hardly affected by drought/disease, scientists are trying to understand the genetic mutations they have that give raise to such abilities. By understanding the science behind the resilience of weeds, one can make agricultural crops less prone to drought/disease.

This got me thinking about invasive species in general. Not just plants but a good number of animal species were introduced to new parts of the world, some intentionally and some accidentally. Here's a non-exhaustive l…

The ATLAS experiment

Hello all. I thought a lot about how to start off with the article, even asked Rahul for articles written by others. I couldn't really figure out how to start so I'll just say something about myself first. My name is Venu and I studied with Rahul for a while in Madras. I'm now a PhD student in the Centre for Particle Physics, Marseille (abbreviated as CPPM) and I work in experimental particle physics. Rahul asked me if I could write something about my work, and I thought of it as a good opportunity to sort out my thoughts as well. Writing an overview often helps me to get a clearer picture of my work. It's like working on one street after another, and forgetting about everything else in the area except that specific street, then going back and getting a bird's eye view or a google maps view of the area that you've worked in. It's quite clear that I talk a lot. I shall try to keep that to a minimum.

There have been a few articles by Patel on particle physic…