Transcript A Star is Born

A Star is Born
(then dies)….
and some planets get made
along the way
Groups of Stars = A Galaxy

What is the name of our galaxy?
Milky Way Galaxy

What type of galaxy are we in?
A spiral galaxy?

What are the other two types?
Elliptical and Irregular
Billions of stars out there.....

The universe has billions and billions of stars
(and countless numbers of galaxies)

In between each star is gas and dust
 Gas

is mostly H (Hydrogen) and He (Helium)
Dust & gas clump together in huge
interstellar clouds called Nebula.
Star clouds = Nebulas

HUGE (takes light 100’s of years to cross)

Gravity pulls matter in the nebula together

Pressure from collisions pushes it back apart

All balanced until........
A nearby star explosion
upsets the balance
Nebula NGC 60
- inside the
Triangulum Galaxy
-estimated distance
2.4 million lightyears away
The "Pillars of Creation"
from the Eagle Nebula
The Eagle Nebula
in its entirety.
Nebulas collapse.....

Gravity causes the nebula to collapse inward
- causing more gravity!!!
(Remember, closer together = stronger gravity!)

Begins to rotate and flatten into a disk shape

Bits of dust stick together when they collide
to form planetesimals (tiny pre-planets)

These collide, stick together & form planets
Nebula gas cloud
starts to collapse
due to gravity
Nebula begins to rotate
Flattens into disk shape
Planetesimals appear
Planets begin to form
Our solar system
Planets form....

Inner planets
-formed from dense pieces, strongly pulled
(due to their mass) by gravity towards the
new star center (called a protostar = baby star)

gas giants
-collected large amounts of gas (H & He)
& smaller bits of dust in the cooler,
outer areas of the spinning nebula
-far enough from sun to also collect ice
Meanwhile......

Center of the nebula
Gas is super compact and hot 10,000,000 ºC
 H begins to fuse together to form He
**called nuclear (or H) fusion
** is the energy of the sun


Very Hotty Burny in here!
From birth to death.....

All stars burn out (run out of H fuel)

A supergiant (100x sun) can explode before
it dies. Then it is called a supernova.

A supernova will become one of two things.
- a neutron star or a blackhole.

Our Sun will become a red giant.
- about 4 billion years from now
Supernova – Huge
star explosiony death