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More Posts from Kimduong-lhp-blog and Others
Astronomy seminar at Tartu Observatory 3 PM, 24-May-2017
Indrek Vurm
“Gamma-ray bursts and their emission mechanisms”
Abstract:
“Gamma-ray bursts (GRBs) are the most energetic explosions in the Universe after the Big Bang. They are observed as sudden flashes of gamma rays from random directions in the sky, lasting from seconds to minutes. GRBs are thought to result from cataclysmic events associated with the birth of a compact object (neutron star or a black hole) either in the collapsing core of a massive star or in a NS-NS or NS-BH merger. Despite being discovered almost half a century ago, the mechanism of their emission is still a matter of active debate. I will review our current understanding of the processes at work and will discuss how detailed numerical modelling can place constraints on the physical conditions at the source as well as the GRB environments.”
Presentation (pdf).
Elle m'a dit d'aller siffler là-haut sur la colline De l'attendre avec un petit bouquet d'églantines J'ai cueilli des fleurs et j'ai sifflé tant que j'ai pu J'ai attendu, attendu, elle n'est jamais venue.
Joe Dassin, Siffler sur la colline
Vivienne Westwood on sex appeal.
Where do stars come from and where do they go?
“It is very poetic to say that we are made from the dust of the stars. Amazingly, it’s also true! Much of our bodies, and our planet, are made of elements that were created in the explosions of massive stars. Let’s examine exactly how this can be.” (NASA’s Educators’ Corner)
The mathematical formula of Happiness (University College London, 2014)
In secret we met -- In silence I grieve, That thy heart could forget, Thy spirit deceive. If I should meet thee After long years, How should I greet thee? -- With silence and tears.
Lord Byron, When We Two Parted
Equinoxes: the products of celestial geometry.
“Because Earth is tilted on its axis, there are only two days a year when the sun shines down exactly over the equator, and the day/night line – called the terminator – runs straight from north to south. On these days, day and night are just about equal lengths across the globe.
In the Northern Hemisphere, the March equinox marks the beginning of spring – meaning that our half of Earth is slowly tilting towards the sun, giving us longer days and more sunlight, and moving us out of winter and into spring and summer.” - NASA
