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Astronomy: The Universe
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The Big Bang theory was found when Edwin Hubble in 1929 discovered that the Universe is expanding. The Belgium astronomer Georges Lemaître was the first to conclude that an expanding Universe must have been much more dense in the past. And this early Universe could have originated with an explosion. George Gamow worked on the ideas of Lemaître. He realized the young dense Universe must have been hot and full of nuclear reactions. In 1950 Fred Hoyle first used the phrase Big Bang to ridicule the theory. But supporters of the Big Bang theory stuck with the phrase Big Bang and it's still used. In the 1960s measurements of the quantities of helium, deuterium and lithium in the Universe matched with the forecasted quantities in the Big Bang theory. And observations of far radiogalaxies left no doubt that the Universe in the past looked very different from the Universe we now know. The most prominent support for the Big Bang theory was the discovery of the Cosmic Microwave Background Radiation (CMB). In the 1940s its existence was foreseen by George Gamow. He realized that the remnant of the Hot Big Bang explosion after billions of years must have cooled down. In 1965 Arno Penzias and Robert Wilson tried to find the source of a radio interference. Their first thought was their antenna was interfered with bird droppings. But the faint radio interference remained and proved to be the CMB radiation. Big Bang versus Big Crunch Another theory is the Big Crunch theory which states that our Universe expands and implodes back to its original state. In this theory we live in an 'closed' Universe. But it is also thinkable that after enough expansion distances have grown enough that a future implosion becomes impossible. This is called an 'open' Universe or a 'very open' Universe. This Universe will cool down - lacking the heat in a next Big Bang - and is also known as the Big Chill. |
Do you want to watch the Cosmic Microwave Background radiation?
When tuning your TV to snow, approximately 1% of the snow is caused by the energy remnant of the Big Bang. |
The cosmic microwave background (CMB) radiationAs said before the CMB radiation is the remnant heat leftover from the Big Bang. Because of the analysis of this remnant astronomers can calculate that the Universe is 13,7 billion years old.Analyses of a new high-resolution map of microwave light emitted only 380.000 years after the Big Bang appear to define our Universe more precisely than ever before. The eagerly awaited results announced in 2003 from the orbiting Wilkinson Microwave Anisotropy Probe resolve several long-standing disagreements in cosmology, which were caused by less precise data than we have now today. Present analysis of the WMAP all-sky image indicate that the Universe is 13,7 billion years old. Our Universe is composed of 73 percent dark energy, 23 percent cold dark matter and only 4 percent atoms. The Universe is currently expanding at the rate of 71 km/sec (accurate to 5 percent) and underwent episodes of rapid expansion called inflation and is thought to expand forever. Astronomers will likely research the foundations and implications of these results for years to come. Related subjects>> Birth of a star and planet formation>> Spacemap: from the Local Group to Earth >> Hubble Deep Field >> Edwin Hubble >> Official WMAP internetsite |
 The development of the Universe from the dawn of time until now.  Image map of the CMB Radiation 380.000 years after start of the Universe made by WMAP  In 1989, an instrument aboard the Cosmic Background Explorer (COBE) satellite measured the CMB radiation. In 2004 more accurate measurements were made by the Wilkinson Microwave Anisotropy Probe. |
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