The big bang By Sofia Garcia 5th Grade - Ms. Parks Franklin Academy Pembroke Pines

What people thought the universe was Up until the 18th century people did not know how the universe started. They did not have a clue of the size of the universe or how the stars and galaxies moved. Humans were not even aware there were other galaxies, so the universe was the sun, moon, and the stars we could see at night.

Georges lemaître He was a Belgian priest and astronomer. Based on astronomy calculations, he came up with the theory of the Big Bang in 1927 saying the universe started as a tiny dense point which exploded and all the elements were created and space went flying in all directions. Not many people thought his theory was correct. Not even the great Albert Einstein.

Edwin hubble He was an American astronomer initially who discovered the universe was more than just the Milky Way. In 1923 he discovered the Andromeda galaxy. In 1929 he had discovered that Andromeda and other galaxies were moving away from each other. This means the universe was getting bigger, and that before it was much smaller, supporting Lemaître’s theory.

One section of the universe After Hubble and the invention of powerful telescopes we now know there are millions of galaxies in space, all of them getting apart from each other at faster and faster speeds. This means that in millions and millions of years people will see no stars in the sky.

Penzias and wilson In the 1960s Arno Penzias and Robert Wilson detected leftover radio waves which they could not explain. The antennas they used were very sensitive and were pointed in the direction where there were no stars, galaxies or planets. Soon after, they realized this was radiation from the Big Bang, again supporting Lemaître’s theory.

Scientists estimated the initial explosion happened 13 Scientists estimated the initial explosion happened 13.7 billion years ago. The universe was contained in a tiny speck called a singularity. Temperatures were extremely high, at about 10,000 million million million degrees! After 300,000 years, when it cooled down to 10,000 ℃, atoms started to form and light started to shine. Galaxies started to form at 1 billion years and continue to create stars up until our days. Nobody knows what happened before the big bang, but this theory is probably true and continues to be studied by many scientists.

References www.Wikipedia.com http://www.bbc.co.uk/science/space/universe/scientists/ar no_penzias_robert_wilson https://www.spacetelescope.org/about/history/the_man_b ehind_the_name/ http://www.amnh.org/education/resources/rfl/web/essaybo oks/cosmic/p_lemaitre.html https://www.youtube.com/watch?v=xhLQ_b3bKdI https://medium.com/starts-with-a-bang/the-big-bang-for- children-67fef10a8625#.oxhz05vqu https://www.brainpop.com/science/space/bigbang/