Astronomy Flashcards
Explain why the evidence available at the time supported the geocentric model (3)
At the time, there was only naked-eye evidence, which indicated that moon/planet/sun appears to move across the sky, in the same direction and same motion everyday.
State two ways you can improve image quality of the telescope
- better quality objective lens
- move telescope to better seeing conditions e.g. dry dessert.
What is red shift?
When the wavelengths from distant galaxies shift towards the red end of the spectrum in order to be longer than they should be- an increase in wavelength.
Some galaxies show greater red shift than others. Explain what this suggests about the universe?
It suggests that the universe is expanding and some galaxies are moving faster than others.
Explain what data can be collected and processed using modern telescopes.
Different wavelengths or frequencies are collected because telescopes are positioned above earths atmosphere.
When astronomers study distant galaxies, they notice change in them describe those changes.
the wavelength increases and frequency decreases for galaxies more distant.
Describe the life cycle of a star that is similar in mass to our sun
It starts off as a nebula which is a cloud of dust and hydrogen gas. Its pulled together by gravity It forms into a main sequence star where hydrogen is converted into helium, nuclear fusion, and light and heat is produced. This then turns into a red giant where the star expands and hydrogen runs out. the star gets colder and uses up all its helium. This eventually collapses into a white dwarf, it becomes very small and dense.
What is a supernova?
The explosion of a massive star
Describe how a nebula becomes a star
When a nebula reaches a critical mass, it collapses due to gravitational attraction. It becomes hotter and forms a protostar which emits light.
Suggest why some red shift of galaxies cannot be detected through the earth’s atmosphere?
Light may have shifted to the infrared region and infrared is absorbed by the atmosphere.
What happens in a black hole?
The gravitational field of a black hole allows nothing to escape. It is formed when a very large star collapses.
Large mass star after main sequence star
red super giant star → supernova. → neutron star, or a black hole
