cosmos midterm review questions

# cosmos midterm review questions - Need pencil, calculator...

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Need pencil, calculator 60 questions, 8 short answers 2-3 sentences D=v/m E=MC^2 question like 72 km/sec? Study questions (Don’t turn in your answers to these questions. Use them to help you study): 1. What falling object did Newton use to verify the inverse square variation with distance of gravity? The moon. Observed qualities, needed something far away, moon best object, inverse square law figured out moon 60 times further away predicted forced would be 3600 times weaker. 2. What object’s orbit didn’t quite match Newton’s “Law” but was explained by general relativity? Mercury. It showed that the inverse square law tends to deviate when an object is close to extremely large masses (Mercury is very close tot he sun, and the sun's great amount of mass causes it to pull on Mercury and Mercury's orbit may change. Orbit should be ellipse and inverse square law predicts that, next time around ellipse should shift a little more. Einstein’s theory of general relativity. Shrinkage of distant. 3. What measurements are needed to determine the radial velocity of a distant galaxy? What physical principle is called upon to infer the velocity from that movement? Look at something distance and watch it is it moving? Moon moving on sky and away or towards. Redshift- convert into velocity… The Doppler Effect. The component of its velocity directed toward or away from us. We need to know where the object is on the spectrum so we can see how much it shifts. 4. What relationship between observable quantities demonstrates that the universe is undergoing uniform expansion? 2 quantities- The velocity - every galaxy is moving away from us…have to also known distant when plot velocity versus distance … slope is Hubble’s Constant. Redshifts occur when the object emitting the radiation is moving away from us, the brightest object he could see each galaxy as a standard candle. The more distant a galaxy, the greater its redshift and the faster it is moving away from us. Hubble’s law says that the more distant galaxies move away from us faster. 5. What makes up dark matter and how is it detected? Dark matter is composed baryonic matter and mostly of WIMPS, weakly interacting massive particles, which do not emit or absorb light, and have no reaction to the Cosmic Microwave Background. We can detect it by its pull on space- time and gravity. Particle only interacts via weak force, it is neutral, fair bit of mass. Detected originally through galaxy rotation curves. Fast enough fall at rate where continue to fall velocity specific. Go in circular orbit specific speed depends on how gravity is pulling. Mass of object determines pull. Something massive that is affecting it. Vast majority of the universe is not composed of atoms

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## This note was uploaded on 03/11/2010 for the course GE CLUST 70A taught by Professor Morris during the Spring '07 term at UCLA.

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cosmos midterm review questions - Need pencil, calculator...

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