Cosmic journey at SISSACosmic journey at SISSA

The astrophysics sector at SISSAThe astrophysics sector at SISSA

Science: processes Science: processes relevant in cosmlogy relevant in cosmlogy and astrophysics, from and astrophysics, from big bang to black big bang to black holesholes

Training: students go Training: students go from passive learning from passive learning to active research in to active research in three or four yearsthree or four years

www.sissa.it/apwww.sissa.it/ap www.sissa.itwww.sissa.it/app/app

Astrophysics Astrophysics Limits in technology and Limits in technology and

funding prevent us to funding prevent us to make particle physics make particle physics experiments as we like on experiments as we like on earth earth

An example? In order to An example? In order to see unification of all forces, see unification of all forces, one should build an one should build an accelerator with the radius accelerator with the radius of the solar system! of the solar system!

The universe around us The universe around us provides an ideal provides an ideal laboratory, from big bang laboratory, from big bang to black holes…so…to black holes…so…

Let’s look at it!Let’s look at it!

Journeying in the cosmosJourneying in the cosmos

Journeying in the cosmosJourneying in the cosmos

The worm Ouroboros

Why do we care?Why do we care? Spending our life and Spending our life and

money to think about money to think about these things, building these things, building strange and expensive strange and expensive machines to probe machines to probe extreme physics… extreme physics…

Why? Only for the Why? Only for the sake of knowledge? sake of knowledge? Pleasure for few? Is Pleasure for few? Is there something for there something for the community? the community?

Why do we care?Why do we care? Spending our life and Spending our life and

money to think about money to think about these things, building these things, building strange and expensive strange and expensive machines to probe machines to probe extreme physics… extreme physics…

Why? Only for the sake Why? Only for the sake of knowledge? of knowledge? Pleasure for few? Is Pleasure for few? Is there something for there something for the community? the community?

The good answer? It’s The good answer? It’s in the switch for the in the switch for the light, turn it on! light, turn it on!

Why do we care?Why do we care? Spending our life and Spending our life and

money to think about money to think about these things, building these things, building strange and expensive strange and expensive machines to probe machines to probe extreme physics… extreme physics…

Why? Only for the Why? Only for the sake of knowledge? sake of knowledge? Pleasure for few? Is Pleasure for few? Is there something for there something for the community? the community?

The bad answer? It’s The bad answer? It’s in the worst weapon in the worst weapon ever (so far) ever (so far)

The big bangThe big bang Ehm…simply, what the hell Ehm…simply, what the hell

was it? physical laws we know was it? physical laws we know fail there, help! fail there, help!

Things that we may reproduce Things that we may reproduce on earth happened 10on earth happened 10-28-28 after after the bangthe bang

Our guesses reach a tiny Our guesses reach a tiny fraction of a second…but…fraction of a second…but…

What was spacetime there? What was spacetime there? Did space get stretched Did space get stretched

immediately after the bang? immediately after the bang? Do we see it? Well, no, but we Do we see it? Well, no, but we

see (and measure, very well see (and measure, very well actually) its echo, through the actually) its echo, through the relic radiationrelic radiation

Contacts: Carlo Baccigalupi, Contacts: Carlo Baccigalupi, Stefano LiberatiStefano Liberati

Courtesy of the NASA WMAP team

The aftermath: darkness and first lightThe aftermath: darkness and first light

When the relic radiation is When the relic radiation is rarefied enough, the universe rarefied enough, the universe is smoothly expanding in the is smoothly expanding in the dark, but without hot dark, but without hot radiation structures may radiation structures may grow…grow…

Eventually dense regions light Eventually dense regions light up, and we see their signature up, and we see their signature today, as their energy today, as their energy extracted the electrons from extracted the electrons from hydrogen in the cosmic hydrogen in the cosmic mediummedium

When did this happen When did this happen exactly? exactly?

What were the engines of first What were the engines of first light? Primordial giant stars? light? Primordial giant stars? Primeval quasi-stellar objects Primeval quasi-stellar objects powered by black holes? powered by black holes?

Contact: Andrea Ferrara Contact: Andrea Ferrara

The galaxies: isles…The galaxies: isles… Hundreds of billions of Hundreds of billions of

stars in each of them, stars in each of them, and we see billions…and we see billions…

How do they work? How do they work? Ellipticals, starburst, Ellipticals, starburst,

spirals, ghost, and…?spirals, ghost, and…? What is their central What is their central

engine? maybe a engine? maybe a black hole for all of black hole for all of them? them?

Contact: Luigi Danese, Contact: Luigi Danese, Paolo SalucciPaolo Salucci

……in an invisible oceanin an invisible ocean Galaxies rotate too fast…stars Galaxies rotate too fast…stars

orbit more mass than we see, orbit more mass than we see, much more, and dark…much more, and dark…

The relic radiation is also a spy of The relic radiation is also a spy of darkness…hot and cold spots darkness…hot and cold spots come from invisible wells and hills come from invisible wells and hills in the early universe…in the early universe…

Our guess…a dark network of Our guess…a dark network of unknown particles is all around unknown particles is all around us…but…us…but…

What are those? Super-world What are those? Super-world particles? Or new forces? particles? Or new forces?

Let’s simulate their graitational Let’s simulate their graitational forces, and compare what we get forces, and compare what we get with what we see…with what we see…

Contact: Paolo Salucci, Riccardo Contact: Paolo Salucci, Riccardo ValdarniniValdarnini

Galactic violenceGalactic violence The milky way is our home, it The milky way is our home, it

looks quiet and steady…looks quiet and steady… But other galaxies are violent, But other galaxies are violent,

they have active nuclei, not to say they have active nuclei, not to say catastrophic…and…catastrophic…and…

Some of them, once per day in Some of them, once per day in the sky, shine of the most violent the sky, shine of the most violent event ever observed, a gamma-event ever observed, a gamma-ray burstray burst

What’s the mechanics of active What’s the mechanics of active galactic nuclei? How exactly the galactic nuclei? How exactly the central black holes power them? central black holes power them?

How many different kinds of them How many different kinds of them exist? exist?

What are the gamma-ray burst? What are the gamma-ray burst? Super-supernovae? Why we see Super-supernovae? Why we see only explosions in the early only explosions in the early universe? Are we in danger? universe? Are we in danger?

Contact: Annalisa CelottiContact: Annalisa Celotti

Challenging EinsteinChallenging Einstein General relativity (Einstein, 1916): General relativity (Einstein, 1916):

gravity as geometry, perhaps the gravity as geometry, perhaps the most elegant theory ever most elegant theory ever formulatedformulated

But also the wildest beast ever! But also the wildest beast ever! Don’t try to match it with quantum Don’t try to match it with quantum

gravity, you’ll hurt yourself! gravity, you’ll hurt yourself! Theories to go beyond that have Theories to go beyond that have

failed so far! failed so far! But the sky is full of objects under But the sky is full of objects under

extreme gravity conditions, let’s extreme gravity conditions, let’s study and model them, for different study and model them, for different gravity models… gravity models…

And even try to reproduce them And even try to reproduce them here, at least on super-computers…here, at least on super-computers…

Extreme gravity excites spacetime, Extreme gravity excites spacetime, producing ripples in spacetime…producing ripples in spacetime…can we try to see those? can we try to see those?

Contacts: Stefano Liberati, John Contacts: Stefano Liberati, John Miller, Luciano RezzollaMiller, Luciano Rezzolla

What? Big Bang today?What? Big Bang today? Mysteries are not enough, so Mysteries are not enough, so

let’s get another onelet’s get another one A mysterious force, the dark A mysterious force, the dark

energy, discovered in 1998, is energy, discovered in 1998, is stretching space apart, today, stretching space apart, today, as it probably did at the Big as it probably did at the Big BangBang

It seems to come from a form It seems to come from a form of energy in the empty of energy in the empty space…space…

No idea of what it is, scientists No idea of what it is, scientists are trying all possible are trying all possible explanation, failing explanation, failing completely so farcompletely so far

The universe will bang again The universe will bang again in a few billions years…in a few billions years…

Contact: Carlo BaccigalupiContact: Carlo Baccigalupi

The sky: a cornucopia for physicsThe sky: a cornucopia for physics

Where from now? Where from now? The road will be decided The road will be decided

substantially by the substantially by the results of observations, in results of observations, in just a few years from now just a few years from now

Which ones? The Planck Which ones? The Planck satellite (relic radiation) satellite (relic radiation) the Large Hadron Collider the Large Hadron Collider (elementary particles), the (elementary particles), the Herschel space telescope Herschel space telescope (physics of galaxies), (physics of galaxies), gravity wave detectors, gravity wave detectors, galactic surveys (dark galactic surveys (dark matter)matter)

The final message: stay The final message: stay tuned…or help!!! tuned…or help!!!