There are lots of kinds of stars Protostars Medium-Sized Stars Red Giant Stars White Dwarfs Massive Stars Let’s see….. There’s Protostars Medium-sized Stars Red Giant Stars White Dwarfs Massive Stars Supernovas Neutron Stars Supernovas Neutron Stars

Protostars A star is born! Fusion begins….. Gravity pulls huge nebulas of hydrogen gas and dust into a single spinning cloud. As the particles crash into each other, the matter heats up….about 15 million degrees. Fusion begins….. Protostars Gravity pulls huge nebulas of hydrogen gas and dust into a single spinning cloud. As the particles crash into each other, the matter heats up…..about 15 million degrees. Fusion begins……The mass begins to shine brightly. A star is born! The mass begins to shine brightly. A star is born!

So what happens next? in the beginning. That depends on the star’s mass in the beginning. What happens next? That depends on the star’s mass in the beginning.

Medium-Sized Stars Hydrogen fuel is fused into helium at the star’s core until the hydrogen is used up. The core shrinks, heats up, & releases energy. The energy causes the star’s outer layers to expand, cool and become redder. Medium-Sized Stars Hydrogen fuel is fused into helium at the star’s core until the hydrogen is used up. The core shrinks, heats up, & releases energy. The energy causes the star’s outer layers to expand, cool and become redder.

The core heats up and releases energy.

The star heats, expands, reddens and becomes a ……

Red Giant The helium core continues to heat. At ~ 200 million degrees the helium atoms fuse to form carbon atoms and the last of the hydrogen gases drift away. Red Giant The helium core continues to heat. At~ 200 million degrees the helium atoms fuse to form carbon atoms and the last of the hydrogen gases drift away.

These drifting gases form a nebula ring around the star. The star is dying. It grows fainter and fainter. Gravity causes its matter to collapse inward. These drifting gases form, a nebula ring around the star. The star is dying. It grows fainter and fainter. Gravity causes its matter to collapse inward. The star is squeezed into a…… The star is squeezed into a……

White Dwarf What are they? They are superdense stars with carbon cores. Since all of the mass of a star the size of our sun has been squeezed into the size of the earth, White Dwarf What are they? They are superdense stars with carbon cores. Since all of the mass of a star the size of our sun has been squeezed into the size of the earth, All of the atoms are crowded together. all of the atoms are crowded together.

They are so packed together….. A chunk of the white dwarf the size of a sugar cube Would equal the mass of a CAR! When the white dwarf’s energy is gone, They are so packed together….. A chunk of the white dwarf the size of a sugar cube Would equal the mass of a CAR! When the white dwarf’s energy is gone, It becomes a dead star. it becomes a dead star.

How long will a star live? Our sun, a medium sized star, will live about 10 billion years. Small stars will live about 100 billion years. Large stars will only live a few billion years.. How long will a star live? Our sun, a medium sized star, will live about 10 billion years. Small stars will live about 100 billion years. Large stars will only live a few billion years…

Massive Stars ……begin with about 6 times as much mass as our sun. Like medium sized stars: They burn hydrogen at first. They redden as their helium core forms. Massive Stars ……begin with about 6 times as much mass as our sun. Like medium sized stars: They burn hydrogen at first. They redden as their helium core forms. But, instead of becoming red giants…. They become supergiants. But, instead of becoming red giants …. they become supergiants.

to oxygen and nitrogen…. As their cores heat up, they fuse from helium…. to carbon….. to oxygen and nitrogen…. As their cores heat up, They fuse from helium….. To carbon….. To oxygen and nitrogen….. To iron. Then the fusion stops. to iron. Then the fusion stops.

They expand into supergiants.

explosion! What happens next? When the fuel runs out, gravity collapses the core even more. The iron core absorbs energy instead of releasing it…. The star breaks apart in a terrific explosion! What happons next? When the fuel runs out, gravity collapses the core even more. The iron core absorbs energy instead of releasing it…. The star breaks apart in a terrific explosion!

A Supernova! The entire sky is lit up for weeks. The temperature can be more than 100 billion degrees. The iron atoms fuse into uranium. The uranium and gases explode into space. A gigantic cloud of gas and dust is left and may become a new nebula. A Supernova! The entire sky is lit up for weeks. The temperature can be more than 100 billion degrees. The iron atoms fuse into uranium. The uranium and gases explode into space. A gigantic cloud of gas and dust is left and may become a new nebula.

Neutron Stars After the supernova explosion of a star 6-30 times the mass of the sun, a neutron star remains. How big is it? It’s only about 16Km in diameter, but it has so much mass packed into it, a chunk the size of a sugar cube Neutron Stars After the supernova explosion of a star 6 – 30 times the size of the sun, a neutron star remains. How big is it? It’s only about 16Km in diameter, but it has so much mass, A chunk of it the size of a sugar cube Has the mass of ~ 100 million cars! has the mass of ~ 100 MILLION CARS!!!

Stars 30 or more times the mass of our sun live even shorter lives and face a strange fate…… After the supernova explosion, the star’s core is so massive, it is swallowed up by its own gravity. Stars 30 or more times the mass of our sun live even shorter lives and face a strange fate….. After the supernova explosion, The star’s core is so massive, It is swallowed up by its own gravity.

Black Hole The core’s gravity is so strong that even light can’t escape. The core has become a….. Black Hole The core’s gravity is so strong that even light can’t escape. The core has become a….. Black Hole

Black holes are like invisible cosmic vacuum cleaners. They swallow both matter and energy. How can we find them if we can’t see them? We can’t, for sure. Matter falling into a black hole releases large bursts of X-rays. Black holes are like invisible cosmic vacuum cleaners. They swallow both matter and energy. How can we find them if we can’t see them? We can’t for sure. Matter falling into a black hole releases large bursts of X-rays. We can detect these. We can detect these.

What happens to this matter? We don’t know. It’s probably squeezed out of existence, just like the star that became the black hole. What happens to this matter? We don’t know. It’s probably squeezed out of existence, Just like the star that became the black hole. The laws of science may be different in a black hole. The laws of science may be different in a black hole.

Big Bang! How was the universe born? No one knows for sure. Some scientists have a theory. Big Bang! They call it the How was the universe born? No one knows for sure. Some scientists have a theory. They call it the Big Bang!

These astronomers believe 18-20 billion years ago all of the matter in the universe was packed into a very dense, very hot spot smaller than a dot! It exploded. Galaxies were formed, These astronomers believe 18-20 billion years ago all of the matter in the universe was packed into a very dense, very hot spot smaller than a dot! It exploded. Galaxies were formed, All of them started racing away from each other. all of them started racing away from each other.

The universe is still expanding. Will it keep expanding? We don’t know. Will its gravity start pulling it back together? The universe is still expanding. Will it keep expanding? We don’t know. Will its gravity start pulling it back together? We don’t know.

Medium-Sized Stars Supernova Protostar Sun Red Giant Nebula White Dwarf Medium-Sized Stars Nebula Protostar Sun Red Biant Supernova White Dwarf Black Dwarf (dead star) Black Dwarf (dead star) Medium-Sized Stars

Massive Stars Neutron Star Supernova Protostar High Mass Red Supergiant High Mass Nebula Very High Mass Massive Stars Nebula Protostar Red Supergaiant Supernova High Mass star Neutron Star Very High Mass star Black Hole Black Hole Massive Stars