Units, Big Bang!

Are we at the Center of the Universe?

Star size comparison.

Speed of Light

How far is a light year? This distance is far greater than any person or spacecraft has traveled, so how do we know? Speed of light 300,000 km/s

1 light year = (speed of light) X (1 year) =

Show calculation...

Astronomical Units (AU)

When we talk about distances in our own solar system, we use Astronomical Units.

Which is the distance between the Earth and Sun.

1 AU = 1.49 X 108 Km

WE USE LIGHT YEARS WHEN MEASURING DISTANCES TO OTHER STARS, SOLAR SYSTEMS, AND GALAXIES.

Parsec FYIA parsec is an astronomical unit of length used to measure distances to objects outside the Solar System. Ab 3.26 light-years.

Largest to smallest parsec>light year>AU

The Big Bang A single confined point of enormously high temperature and density

The universe began to expand at a furious rate

The Big Bang took place ≈ 13.7 Billion YA

Hubble’s law evidence 1In 1929, Edwin Hubble announced that almost all galaxies appeared to be moving away from us!

In fact, he found that the universe was expanding - with all of the galaxies moving away from each other. This phenomenon was observed as a redshift of a galaxy's spectrum.

v = H x d

Cosmic Background Radiation # 2

Cosmic background radiation is electromagnetic radiation from the sky with no discernible source.

Its discovery and detailed observations of its properties are considered one of the major confirmations of the Big Bang.

Composition of the Cosmos 3Hydrogen and helium account for nearly all the nuclear matter in today's universe.

25% by mass and hydrogen about 73% with all other elements constituting less than 2%.

Fate of the UniverseThe Big rip Dark energy out does gravity and rips the universe apart.

The Big Crunch gravity will eventually pull the universe back together.

The Big Chill expansion will slow down but never stop