SCI ♡ Life Cycle of a Star

Stars

• huge celestial bodies made of gases

• can produce light and heat through nuclear fusion inside their cores

• building blocks of galaxies

• there are billions in the universe

Light Years

• stars are so far away that distances between them are measured in _____

• distance traveled by light in one year

• 9.5 trillion kilometers

• sun is the closest star to us

Light Elements

• hydrogen

• helium

• lithium

• beryllium

Heavy Elements

• carbon

• nitrogen

• iron

“stellar”

star

“nucleosynthesis”

formation of stars

Big Bang Theory

• Edwin Hubble (1929)

• 13.7B years ago

• expansion of space

• as the universe expands it cools

Cycle of a Star

1. Nebula

2. Protostar

3. Main Sequence Star

4. Red Giant Star

5. White Dwarf

6. Supernova

Nebula

• stars form in nebulae

• which are clouds of gas and dust

Protostar

• formed when a dense region of molecular cloud collapses

• fragments of clouds contract and form a stellar core

• young star that is still gathering mass from a cloud

  of gas and dust

Main Sequence Star

• nuclear reactions in the center (or core) of stars generate enough energy

• to keep them shining brightly for many years

Red Giant Star

• large, bright, and cool star

• nearing the end of its life

• formed when a star runs out of hydrogen fuel

• begins to die

White Dwarf

• small, dense, hot star

• remnant of a dying star

• formed when a star runs out of nuclear fuel

• sheds its outer layers

Supernova

• massive explosion

• occurs when a star dies

• largest explosion known to happen in the universe

Diurnal Motion

• as the Earth rotates, your position on Earth changes relative to the stars

• makes it appear as though the constellations move across the sky throughout the nigh

• like the Sun 'moves' from East to West each day

Earth’s Orbit

• the _____ orbits the Sun

• takes around 365 days to orbit the Sun

• which is why our calendar year is 365 days long

• also affects how we view constellations

Annual Motion

• throughout the year, constellations gradually shift West due to Earth's revolution around the Sun

• since the Earth faces a different direction each season, some constellations are only visible during certain times of the year