Universe Flashcards
What is the age of the Earth?
4.6 Billion years old
What is the age of the universe?
13.8 Billion years old
When viewed from Melbourne, how do stars and planets move across the night sky?
Rise in the east, set in the west, rotating about the South Celestial Pole
When viewed from the South Pole what is the motion of stars?
Stars rotate about the zenith and only half the possible stars are ever seen
What is the altitude of a star?
The angle above the horizon
What is the azimuth of a star?
The compass bearing of a star, clockwise from North
What is the zenith of a star?
The point directly overhead at 90 degrees above the horizon
Why is the name planet appropriate given ancient observations of planets?
Greek astronomers would observe planets in different positions every night, relative to the fixed background of distant stars
What is the name of stars which are located near celestial poles and can always be seen?
Circumpolar stars
What is the significance of the ecliptic?
It is an imaginary line along which the sun and the planets appear to move as they cross the sky
What causes the Earth’s seasons?
The tilt of the Earth’s axis
What is the name of the star located at the North Celestial Pole?
Polaris
At the equator, if a star rises in the east at 8PM, at what time will it be directly overhead?
2 am
Why do we see different stars rising at the same time each night over the course of a year?
Because the Earth is in a different orbit around the sun every day and during different seasons we see different stars
How is the Bayer naming system applied to the Beta Orionis?
The brightest star in a constellation is usually named Alpha, but in this star the brightest star is named Beta
What is the shape of our solar system?
A flat disc shape, with planets all rotating about the sun in the same direction
What is significant about the Southern Cross and the Pointers for observers in the Southern Hemisphere?
They are circumpolar constellations that never set below the horizon
What is significant about the star Polaris, which is only visible to those in the Northern Hemisphere?
It is located at the North Celestial Pole and all stars in the Northern Hemisphere sky rotate about it
What is the distance of a light year in kilometres?
9.47X 10 power of 12 km
