The Nobel prize in Physics 2006

piet mulders

VUOctober 4, 2006

pjg.mulders@few.vu.nl

Physics2006

• John C. Mather (1946)NASA Goddard Space Flight Center, Greenbelt, MD, USA(PhD from Berkeley)

• George F. Smoot (1945)University of California, Berkeley, CA, USA(PhD from MIT)

for …

For their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation

From www.nobel.se:The Nobel Prize in Physics 2006 has been awarded to U.S. physicists John Mather (NASA) and George Smoot (LBL) for their discovery of the basic form of the cosmic microwave background radiation as well as its small variations in different directions. The very detailed observations that the laureates have carried out from the COBE satellite have played a major role in the development of modern cosmology into a precise science.

Measuring temperatures in the universe

max

1~T

Looking at the color (maximum of light emission) or more general to the form of the emission spectrum

4~Energy T

These emission shapes can also be created in a lab and were first described by Max Planck (Nobel prize 1918)

History of the CMB

• Expanding universe (Friedmann 1922, Lemaitre 1927, Willem de Sitter) and redshift (Edwin Hubble 1929)

• Richard Tolman (working with Hubble) showed in 1934 that cooling blackbody radiation in an expanding universe retains its form

• Prediction of Cosmic Background Radiation (George Gamov 1948; Ralph Alpher and Robert Herman 1950)

• Accidental observation of Cosmic Microwave Background (CMB) at Bell Labs by Arno Penzias & Robert Wilson 1965 (Nobel prize 1978)

• Robert Dicke, Peebles, Roll and Dave Wilkinson 1965 realized immediately that CMB had been found!

Origin of the CMB

BIG BANG

13.7 billion years ago

inflatie

and finally now …

History of COBE satellite

• Announcement of NASA of opportunities for small space-based experiments in 1974

• COBE mission (delayed by 1986 shuttle accident) is launched by rocket in 1989 (Mather)

• Measurement of shape of CMB shows a perfect Planckian shape with T= 2.726 K (Smoot 1990)

FIRAS

FIRAS optical paths

The COBE satellite

T = 3 mK

T = 2.728 K

T = 20 K

DMRMeasurements of fluctuations in the CMB ~ 10-5 K

,T 2.7248K 2.7252K

Temperature maps of sky

COBE and WMAP

T = 2.728 K

T ~ mK

T ~ 10 K

• Uniform distribution

• Absence of other mK variations gives support to inflation models and dark matter

• A dipole effect corresponding to the motion of Earth with respect to CMB rest frame (about 600 km/s)

• Effect of our own galaxy (choosen as the equator of the projection)

• Quadrupole (Sachs/Wolfe)

, ,lm lmaT Y ,T

2.7248K 2.7252K

l

Angular momentum Spectrum

0.4 100.3(6.5 ) 10baryonen

fotonen

N

N

Cosmology becoming a precision science

WMAP data

Future of CMB research

• COBE (1989-1993)• WMAP (2001-present)• Planck

Planck is part of the ESA Horizon 2000 Scientific Program. Its scientific goal is to measure the CMB anisotropies at all angular scales larges than 5-10’ over entire sky with a precision of 2x10-6

It is planned to launch Planck in the first quarter of 2007. After launch, Planck will be directed to the second Lagrangian point of the Earth-Sun System.

1.5 x 106 km

• Combine with other ‘messengers from universe’– Neutrinos (ANTARES, AMANDA,

KM3NET)– UHECR (Auger, LOFAR)– Gravitational waves (VIRGO, LISA)

Summary

• An excellent decision of the Nobel committee

• COBE and follow-up mission WMAP have changed our view of the universe

• Cosmology has become a precision science• Dark matter is no longer exotic and in

combination with other experiments (astronomical and lab experiments at LHC) within reach

• The history of the early universe (with scenarios like inflation) come within ‘experimental reach’

dark matter

baryons

dark energy

visible, gravitational (blue) and X-ray (red) picture of bullet cluster