Our Universe How we wonder what you are

Our observed universe

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Earth rise: our home in perspective

Alam Semesta Kita Apa yang dipelajari? Ukuran dan bentuknya Di mana kita Sejarahnya dan sejarah kita, masa depan Agar muncul apresiasi (pemberian makna?) terhadap kehidupan dan seluruh alam semesta ini. Dalam prosesnya: muncul apresiasi terhadap segala usaha manusia, menggunakan pikiran dan nuraninya, untuk memahami apa yang sesungguhnya melampaui batas fisiknya. Bagaimana caranya?

Bentuk dan Ukuran

Menurut Einstein… Teori Relativitas Umum Bentuknya bergantung pada banyak dan jenis isi alam semesta. Ukurannya dinamis (Friedmann)

Standard Cosmology Homogeneous and Isotropic on largest scale (1) Cosmological Principle (Principle of Mediocrity): Homogeneous and Isotropic on largest scale We do not occupy special point in the universe Robertson-Walker geometrical description (2) Gravity predominates on large scale (3) General Relativity (1) + (2) + (3) : Friedmann-Lemaître dynamical model

Friedmann-Lemaître-Robertson-Walker Universe expands and cools Initial singularity at finite time in the past Supporters: Galaxy recessional motion Cosmic Microwave Background Radiation Abundance of primordial elements Large scale structure formation

In agreement with Hubble

Galaxies are receding Speed = Ho x distance blueshift Redshift But we are not at the centre ! (Cosmological Principle)

The universe is expanding

But how fast ? Back to square one: - measure distance - counting galaxies - weighing galaxies Use Friedmann model (assumed values of parameters) Look for independent methods (known astrophysics)

Measuring distance using Supernovae Type Ia

Supernovae Type Ia intrinsic property understood

Hubble diagram accelerating universe ?

Independent method Illustration on age determination (cf. model: age proportional to 1/Ho)

Abundance of primordial elements

Counting galaxies APM. Maddox et al

Weighing galaxies dark matter ‘found’

Weighing cluster of galaxies X-ray from hot gas Gravitational lensing (all mass)

Looking through the lens (darkly) Honest-to-God mass probe Strong lensing effect Kneib et al

The very large scale Cosmic Microwave Background WMAP

CMB (very !) old tunes First generation of photons managed to liberate from scattering by matter Last scattering surface (400 thousand years after the Big Bang) Very redshifted: now detected at (2.7 ± 0.00001) K

But life is complicated… Galaxy cannibalism exist

History of the universe albeit sketchy

All in all from quantum fluctuations to galaxies ?

Supernovae, CMB, and Galaxies Suggestion: flat universe with little contribution from known matter, and large contribution from unknown entity

Early Universe Haven of speculations Neil Turok’s

Current and future missions WMAP: measure CMB temperature distributions Planck: measure CMB temperature distribution and polarization (due to gravitational wave during inflation) SNAP: measure distance to very distant supernovae etc

So, where are we?

Still lots to uncover