CIRCLE WITH A DOT

@sundogplanets #SpaceX’s proposal to launch a million satellites is astronomical vandalism. #satellite #astronomy

@mustapipa That's really interesting. Were the managed forests at a variety of times following harvest? If so, how correlated was C storage with time since harvest?

@sposadelvento @VoiceofDuum The key to these differences is that each successive fusion stage requires greater stellar core compression in order to overcome the natural repulsion between positively charged atomic nuclei of increasing mass & charge. Low mass stars can't generate the required core compressions for higher-level nuclear fusion reactions, & also lower compressions mean lower fusion reaction rates, hence the vastly longer lives of low mass stars. 3/3 #astronomicalTruths

@sposadelvento @VoiceofDuum The most important determinant of stellar evolution is stellar mass. Massive blue stars run through fusion reactions up to Fe & then explode in supernovae, & the whole process takes just a few million years. Fe is the energy well of the universe. Fusion of lighter elements yields energy, while fission of heavier ones yields energy. Tiny red dwarfs don't reach the He -> C stage, but take hundreds of billions of years to become white dwarfs. 2/3 #astronomicalTruths

@sposadelvento @VoiceofDuum No. In about 5 billion years the sun's core supply of H will have been mostly converted to He via nuclear fusion that currently provides us with energy, & then the sun will expand to become a red giant with its surface just inside the Earth's orbit. At that point the core will engage in a He -> C fusion reaction. After a few hundred million years the core will be choked up with C and then it will collapse to become a white dwarf star. 1/3 #astronomicalTruths