Astro 101 10-15 - Astro 101 10-15-08 Lecture 18 What forces...

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Astro 101 Lecture 18 10-15-08 What forces work in opposite directions to keep a star from collapsing or expanding? Gravity and pressure Energy Generation in stars T Tauri stars Named after the first one found Newly formed stars which are just clearing away the surrounding material. Surface eruptions, rapid variations of light output and mass loss via a “wind” Many are surrounded by disks!! Could planets be forming there? Sun was probably once a T Tauri star Bipolar outflows What makes the sun shine? The sun emits 4 x 10 ^26 Watts People power about 600 billion Watts US power consumption about 10^13 Watts Equivalent to >100 billion nuclear bombs/sec We know from dating of rocks on the Earth and Moon, that the Sun is at least 4.5 billion years old. Need about 6x10^43 energy Possible energy sources stars Chemical Reactions Such as burning fire Sun’s lifetime would be ~1000 years! Gravitational Compression Shrinking – use gravity, like a waterfall Must collapse 50 ft per year!! Sun’s lifetime would be 15 mil years
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Astro 101 10-15 - Astro 101 10-15-08 Lecture 18 What forces...

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