Astr 102 exam questions - Study guides, Class notes & Summaries

How much time is there between when a star rises and when it sets? - it depends on the star You go out tonight and see the brightest star in the constellation Orion just rising above your eastern horizon at 10 PM. One week later at 10 PM this same star will be - slightly higher in the sky. One night, you see the star Sirius rise at exactly 7:36 PM. The following night it will rise - slightly earlier.

he 'size' of a black hole is given by the Schwarzchild radius. For the earth this is about 1 cm. This means that: - if the earth were somehow to be shrunk to this size, gravity would win and there would be an inevitable collapse to a 'singularity' at the center In addition to supernovae formed from the collapse of massive stars as they run out of fuel, supernovae of another kind are produced when: - a white dwarf near the 'Chandrasekhar limit' has extra matter dumped onto it from a co...

What is a falling star? - Debris from a comet or asteroid that has fallen and is evaporating. What is the farthest object in our Solar System? - The Oort Cloud Describe the Oort Cloud - 1. Made up of Comets - icy dirty glaciers 2. Comets: the melted debris that is trailing behind us because it is being pulled by the Sun and shrinking and melting.

Life expectancy of a 10Msun star - Answer 10 million years: life expectancy of a _______Msun star life expectancy of a .1 Msun star - Answer 100 billion years: life expectancy of a _______Msun star Coolest stars: ___________ K - Answer 3,000 K Hottest stars: ___________ K - Answer 50,000 K Least luminous stars: 10^_____ Lsun - Answer 10^-4 Lsun

Which of the following statements about light focusing is not true? A) In a healthy eye, light is focused on the retina. B) Film should be placed at the focal plane in a camera. C) If you try to look at an image that is not formed at the focal plane, it will be blurry. D) The focal plane of a reflecting telescope is always located within a few inches of the primary mirror. - Answer D) The focal plane of a reflecting telescope is always located within a few inches of the primary mirror

When the sun becomes a red giant its luminosity will be _____________ times what it is now - 2000 When a star first moves off the HR diagram, its radius _________________ and its surface temperature ____________________ - increases, decreases If a white dwarf is able to gain enough mass to exceed ____ solar masses, its self-gravity will be stronger than electron degeneracy pressure, and the star will collapse. As it does so, its temperature increases to the point that ______________ can un...

The apparent motion of a foreground object relative to a distant background as the observers position changes? - Parallax When measuring parallax the distance between two observation points is called? - Baseline If Earth rotated twice as fast as it currently does, but its motion around the Sun stayed the same, then? A. The night would be twice as long B. The night would be half as long C. The year would be half as long D. The length of the day would be unchanged. - B. A long, thin cloud ...

The celestial sphere - An imaginary sphere surrounding Earth to which the stars are attached. Ancient astronomers believed the sky was a great sphere surrounding Earth with the stars stuck on the inside like thumbtacks. Modern astronomers know that the stars are scattered through space at different distances, but it is still convenient to think of the sky as a great starry sphere enclosing Earth. celestial sphere - the eastward rotation of Earth causes the Sun, Moon, planets, and stars to m...

What is the period of the solar magnetic cycle? a)27 days b)1 year c)11 years d)22 years e)220 years - 2: What is the period of the solar magnetic cycle? a)27 days b)1 year

What is meant by spectral resolution? A) It is a measure of how much energy an object emits in different parts of the electromagnetic spectrum. B) It is a measure of how close two spectral lines can be distinguished. C) It is a measure of how close two point sources can be distinguished. D) It is the same as angular resolution when applied to telescopes operating at different wavelengths. - B) It is a measure of how close two spectral lines can be distinguished.