Cosmic journey at SISSA

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Cosmic journey at SISSA
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The astrophysics sector at SISSA

• Science processes relevant in cosmlogy and
  astrophysics, from big bang to black holes
• Training students go from passive learning to
  active research in three or four years
• www.sissa.it/ap
• www.sissa.it/app

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Astrophysics

• Limits in technology and funding prevent us to
  make particle physics experiments as we like on
  earth
• An example? In order to see unification of all
  forces, one should build an accelerator with the
  radius of the solar system!
• The universe around us provides an ideal
  laboratory, from big bang to black holesso
• Lets look at it!

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Journeying in the cosmos
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Journeying in the cosmos
The worm Ouroboros
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Why do we care?

• Spending our life and money to think about these
  things, building strange and expensive machines
  to probe extreme physics
• Why? Only for the sake of knowledge? Pleasure
  for few? Is there something for the community?

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Why do we care?

• Spending our life and money to think about these
  things, building strange and expensive machines
  to probe extreme physics
• Why? Only for the sake of knowledge? Pleasure
  for few? Is there something for the community?
• The good answer? Its in the switch for the
  light, turn it on!

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Why do we care?

• Spending our life and money to think about these
  things, building strange and expensive machines
  to probe extreme physics
• Why? Only for the sake of knowledge? Pleasure
  for few? Is there something for the community?
• The bad answer? Its in the worst weapon ever (so
  far)

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The big bang

• Ehmsimply, what the hell was it? physical laws
  we know fail there, help!
• Things that we may reproduce on earth happened
  10-28 after the bang
• Our guesses reach a tiny fraction of a
  secondbut
• What was spacetime there?
• Did space get stretched immediately after the
  bang?
• Do we see it? Well, no, but we see (and measure,
  very well actually) its echo, through the relic
  radiation
• Contacts Carlo Baccigalupi, Stefano Liberati

Courtesy of the NASA WMAP team
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The aftermath darkness and first light

• When the relic radiation is rarefied enough, the
  universe is smoothly expanding in the dark, but
  without hot radiation structures may grow
• Eventually dense regions light up, and we see
  their signature today, as their energy extracted
  the electrons from hydrogen in the cosmic medium
• When did this happen exactly?
• What were the engines of first light? Primordial
  giant stars? Primeval quasi-stellar objects
  powered by black holes?
• Contact Andrea Ferrara

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The galaxies isles

• Hundreds of billions of stars in each of them,
  and we see billions
• How do they work?
• Ellipticals, starburst, spirals, ghost, and?
• What is their central engine? maybe a black hole
  for all of them?
• Contact Luigi Danese, Paolo Salucci

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in an invisible ocean

• Galaxies rotate too faststars orbit more mass
  than we see, much more, and dark
• The relic radiation is also a spy of darknesshot
  and cold spots come from invisible wells and
  hills in the early universe
• Our guessa dark network of unknown particles is
  all around usbut
• What are those? Super-world particles? Or new
  forces?
• Lets simulate their graitational forces, and
  compare what we get with what we see
• Contact Paolo Salucci, Riccardo Valdarnini

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Galactic violence

• The milky way is our home, it looks quiet and
  steady
• But other galaxies are violent, they have active
  nuclei, not to say catastrophicand
• Some of them, once per day in the sky, shine of
  the most violent event ever observed, a gamma-ray
  burst
• Whats the mechanics of active galactic nuclei?
  How exactly the central black holes power them?
• How many different kinds of them exist?
• What are the gamma-ray burst? Super-supernovae?
  Why we see only explosions in the early universe?
  Are we in danger?
• Contact Annalisa Celotti

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Challenging Einstein

• General relativity (Einstein, 1916) gravity as
  geometry, perhaps the most elegant theory ever
  formulated
• But also the wildest beast ever!
• Dont try to match it with quantum gravity,
  youll hurt yourself!
• Theories to go beyond that have failed so far!
• But the sky is full of objects under extreme
  gravity conditions, lets study and model them,
  for different gravity models
• And even try to reproduce them here, at least on
  super-computers
• Extreme gravity excites spacetime, producing
  ripples in spacetimecan we try to see those?
• Contacts Stefano Liberati, John Miller, Luciano
  Rezzolla

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What? Big Bang today?

• Mysteries are not enough, so lets get another
  one
• A mysterious force, the dark energy, discovered
  in 1998, is stretching space apart, today, as it
  probably did at the Big Bang
• It seems to come from a form of energy in the
  empty space
• No idea of what it is, scientists are trying all
  possible explanation, failing completely so far
• The universe will bang again in a few billions
  years
• Contact Carlo Baccigalupi

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The sky a cornucopia for physics

• Where from now?
• The road will be decided substantially by the
  results of observations, in just a few years from
  now
• Which ones? The Planck satellite (relic
  radiation) the Large Hadron Collider (elementary
  particles), the Herschel space telescope (physics
  of galaxies), gravity wave detectors, galactic
  surveys (dark matter)
• The final message stay tunedor help!!!