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Monday, April 26, 2010

ATLAS detector at LHC

ATLAS is the detection device at LHC. It’s here where the collision between protons happens at high speed.

Actually ATLAS is at this stage:

Collision Energy: 7 TeV (3.5 + 3.5) 
Maximum Luminosity = 12 x 1027 cm-2s-1
Total Collisions (a 7 TeV) = 56,000,000

Image with the events in the 7 TeV collision:

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image: ATLAS.ch (CERN)

“(…) two W-boson candidates were identified on Tuesday April 6th. ATLAS is the first (and so far, only) LHC experiment to have spotted W candidates, one decaying to an electron and a neutrino, and the other to a muon and a neutrino.” www.atlas.ch (13 Abril 2010)

Tuesday, April 13, 2010

20 years of Hubble

The Hubble Space Telescope (HST) is a space telescope that was carried into orbit by the space shuttle in April 1990. Although not the first space telescope, Hubble is one of the largest and most versatile, and is well-known as both a vital research tool and a public relations boon for astronomy.

Launched in 24 April 1990, the HST carried five scientific instruments: the Wide Field and Planetary Camera (WF/PC), Goddard High Resolution Spectrograph (GHRS), High Speed Photometer (HSP), Faint Object Camera (FOC) and the Faint Object Spectrograph (FOS). WF/PC was a high-resolution imaging device primarily intended for optical observations. It was built by NASA's Jet Propulsion Laboratory, and incorporated a set of 48 filters isolating spectral lines of particular astrophysical interest. The instrument contained eight charge-coupled device (CCD) chips divided between two cameras, each using four CCDs.

Important discoveries

One of Hubble's most famous images, "pillars of creation" shows stars forming in the Eagle Nebula

Hubble has helped to resolve some long-standing problems in astronomy, as well as turning up results that have required new theories to explain them. [...]Before the launch of HST, estimates of the Hubble constant typically had errors of up to 50%, but Hubble measurements of Cepheid variables in the Virgo Cluster and other distant galaxy clusters provided a measured value with an accuracy of 10%.

While Hubble helped to refine estimates of the age of the universe, it also cast doubt on theories about its future. Astronomers used the telescope to observe distant supernovae and uncovered evidence that, far from decelerating under the influence of gravity, the expansion of the universe may in fact be accelerating. This acceleration was later measured more accurately by other ground-based and space-based telescopes, confirming Hubble's finding.

The high-resolution spectra and images provided by the HST have been especially well-suited to establishing the prevalence of black holes in the nuclei of nearby galaxies. [...]

in wikipedia


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