Survey of the Universe Tom Burbine

Chemistry The science of matter and the changes it undergoes.

Atoms Atoms are made up of 3 types of particles Protons – positive charge (+1) Electrons – negative charge (-1) Neutrons – neutral charge (no charge) Protons and Neutrons are found in the nucleus

Elements Different elements have different numbers of protons The properties of an atom are a function of the electrical charge of its nucleus

Definitions Atomic Number – Number of protons Atomic Mass – Number of protons and neutrons U 235 – atomic mass 92- atomic number Isotopes – Same number of protons but different numbers of neutrons

Periodic Table A chart in which all known elements are listed in order of atomic number

Period – Horizontal row Across any period, the properties of elements change Group – Vertical column Down any group, the properties of elements are very similar

Radioactivity Radioactivity – decay of an atomic nucleus All elements with an atomic number greater than 82 (lead) are radioactive

Bohr’s Planetary Model Electrons orbit the nucleus in specific energy levels Level n=1 is closest to nucleus Level n=2 is second closest

Shell Model Electrons behave as they are arranged in a series of concentric shells around the nucleus Innermost shell can contain 2 electrons The second and third shells can contain 8 electrons each The fourth and fifth shells can contain 18 electrons each

Ion Ion – an electrically charged particle created when an atom either loses or gains one or more electrons

4 Forces that operate in the universe Gravity Electromagnetism Strong Force Weak Force

Examples of elementary particles Quarks – make up protons and neutrons Electrons Neutrino – almost massless particle with no charge that travels almost at the speed of light Photons – particles of light

Celestial Sphere an imaginary sphere of infinite extent on which all celestial objects appear to lie

Celestial Sphere

Terminology for looking at the sky

What is a constellation?

Constellations People refer to constellations as a pattern of stars Astronomers refer to constellations as specific regions of the sky In 1928, the IAU (International Astronomical Union) decided there were 88 constellations Many of the constellation names go back thousands of years

Constellations The constellations are totally imaginary things that poets, farmers and astronomers have made up over the past 6,000 years (and probably even more!). The real purpose for the constellations is to help us tell which stars are which, nothing more.

What is this constellation?

Orion Bigger the star, the brighter it is

Orion was the son of the god of the sea, Poseidon and a great hunter. One story is that he made an enemy of Hera who sent a scorpion to sting him. Orion was restored to health by Ophiuchus, the first doctor of medicine. Another story is that Artemis was Tricked by Apollo to shoot an arrow at Orion. When he died, Poseidon asked Zeus to put him among the stars.

Ursa Major Ursa Major, the Great Bear, was identified with a bear by native American Indians of the Northeastern United States and the ancient Greeks. The name common in Britain, the Plough, seems to have a medieval origin, Another common name among northern European cultures is the Wain, a shortened form of wagon

What are the constellations named after 14 men and women 9 birds 2 insects 19 land animals 10 water creatures 2 centaurs one head of hair a serpent a dragon a flying horse a river 29 inanimate objects

Why don’t all the constellations have ancient names?

Ancient cultures such as the Greeks and Egyptians could not see the constellations in the Southern Hemisphere

Polaris Polaris is called the North Star Brightest star in the constellation Ursa Minor Does not appear to move in the night sky It is very close to the north celestial pole, making it the current northern pole star. 48th brightest star in the night sky

Any Questions?