@?astrophysics

Flashcards 2022-01-26 What simplifying model do we use when talking about emitters and absorbers of electromagnetic radiation?? Black bodies. What two main assumptions are made about a black body?? They are perfect emitters and absorbers of electromagnetic radiation They emit radiation at all wavelengths Why is the sun yellow if it can be modelled as a near-perfect black body?? Because it is hotter than its surroundings and so is glowing. What is special about how a black body emits radiation at all wavelengths?

Flashcards 2022-01-25 What is this?? A Hertzsprung-Russell diagram. What is on the $x$-axis of a Hertzsprung-Russell diagram?? Temperature. Which out of luminosity and temperature goes in the wrong direction on a Hertzsprung-Russell diagram?? Temperature. What is on the $y$-axis of a Hertzsprung-Russell diagram?? Luminosity. What is sometimes confusing about the temperature values on a Hertzsprung-Russell diagram?? They measure “effective temperature”, not the temperature of the core. What are the units for luminosity measured on a Hertzsprung-Russell diagram?

Flashcards 2022-01-18 What are the four characteristics of a planet (ORFC)?? It is in __O__rbit around a star It has a mass large enough that gravity makes it __R__ound It has no __F__usion reactions It has __C__leared its orbit of most other objects What is the difference between a planet and a dwarf planet?? A dwarf planet has not cleared its neighbourhood. What is an asteroid?? An small, uneven and un-icy object that orbits the sun.

Flashcards 2022-01-18 What is the first stage in the evolution of a star?? A nebula. What is the main element in a nebula?? Hydrogen. What happens to a nebula after a long period of time?? It collapses under its own gravity. As a nebula is collapsing under its own gravity, what happens to the stores of energy?? The gravitational potential potential is transfered to kinetic energy. What happens as the gravitational energy of the dust particles in a nebula is transferred to kinetic energy?