Stars and the Star life Cycle How do stars live out their lives? What is the difference between mass and size? This Photo by Unknown Author is licensed under CC BY-NC

What is a star? https://ed.ted.com/lessons/the-life-cycle-of-a- neutron-star-david-lunney A Star is sphere of matter where nuclear fusion is occurring Nuclear fusion is when the nuclei of two atoms are pressed together under such pressure that they combine into one nucleus What is the difference between a star and a planet? This Photo by Unknown Author is licensed under CC BY-SA

What is electromagnetic radiation? Electromagnetic radiation is energy that travels through space in waves The light you see is just a part of the electromagnetic specrum Objects in space give off all kinds of radiation This Photo by Unknown Author is licensed under CC BY-NC-ND What is electromagnetic radiation?

Electromagnetic spectrum This Photo by Unknown Author is licensed under CC BY-SA The different labels refer to the different wavelengths of energy Wavelength is the distance from the crest of one wave, to the crest of the next wave Glue your copy of the electromagnetic spectrum into your journal now

Telescopes Telescopes are instruments what collect and focus light and other forms of electromagnetic radiation The Hubble telescope is constantly collecting images of space using all kinds of electromagnetic radiation The pictures in this powerpoint are of several different types of electromagnetic radiation http://hubblesite.org/ This Photo by Unknown Author is licensed under CC BY-SA

Lives of Stars A star is born in a nebula They are born when this contracting cloud of gas and dust becomes so dense and hot that nuclear fusion occurs. How long it lives depends on its mass This Photo by Unknown Author is licensed under CC BY-SA Lives of Stars

Star Nursery A nebula is a large could of gas and dust spread out in an immense volume Remember all matter has mass, and all mass has gravity The densest part of the nebula pulls the matter around it in Once there is enough mass, nuclear fusion occurs This Photo by Unknown Author is licensed under CC BY-SA-NC

Once nuclear fusion begins, the star is called a protostar There is still matter in the form of gas and dust that will still add to the star’s mass During nuclear fusion, enormous amounts of energy are released This Photo by Unknown Author is licensed under CC BY-SA Early Stages

Lifetimes of Stars How long a star lives depends on it’s mass The larger the mass of a star, the faster it suns out of fuel The most massive stars are blue, like the hottest part of the flame in a fire The coolest stars have the least mass and are red Remember mass and size are not the same This Photo by Unknown Author is licensed under CC BY-SA

What happens when a star runs out of fuel? After a star runs out of fuel, it becomes a white dwarf, a neutron star, or a black hole Only the most massive stars become black holes The Sun will grow to a red giant, engulf Mercury, Venus and Earth, then keep expanding its outer layer out into space Only the core, a white dwarf will remain This Photo by Unknown Author is licensed under CC BY-NC What happens when a star runs out of fuel?

Supernovas When a massive star runs out of fuel, it will collapse to the core, and fuse heavier elements and expand back out This will happen several times until the core of the star is fusing iron Once iron is formed, a star cannot form any heavier elements It will collapse and the in a final explosion, form all of the heavier elements we know today in what is called a supernova https://www.neok12.com/video/Stars/zX7a5c744f6 16509440c7c06.htm This Photo by Unknown Author is licensed under CC BY-SA

After a supernova There are two results of a supernova Neutron stars – can also be pulsars Black holes – we don’t know much Black holes are not holes at all Black holes are places where there is so much mass, and so much gravity in such a small space, that the gravity does not even let light (electromagnetic radiation) out This Photo by Unknown Author is licensed under CC BY-SA