Astronomy Flashcards
What shape is the earth
An oblate spheroid
Why is the earth the shape it is?
It is squashed slightly by the earths spin
The earths major divisions from the surface down
Crust, mantle, outer core, inner core
The depth of the centre of the earth
6500km
What is the difference between 50°n and 50°s
50°n is 50° above the equator and 50°s is 50° below the equator
What are the poles?
The poles are the points at which the axis of the earths rotation meets the surface. They are 90°N and 90°S
What is the prime meridian?
A line of longitude. 0°E and 0°W. It runs through London and everywhere north or south of Greenwich.
Define the Tropic of Capricorn and the Tropic of Cancer
The Tropic of Capricorn is the most southerly line of longitude and the Tropic of Cancer is the most northernly line of longitude
What is the arctic circle
Circles where there are days that the sun never rises and never sets
What is twinkling
Light refracting through the atmosphere before it reaches the eye
What is skyglow
Reflected light from things like street lamps or cities
Why is skyglow a problem?
It reduces contrast and so you can’t see some dimmer stars
Meteors
A trail of debris from a comet in space
Meteoroid
a rock in a comets debris trail
Meteorite
A rock that makes it to the earths surface
Micrometeorite
A small rock that makes it to the earths surface
A fireball
A very bright meteoroid
What is solar wind made of?
Mostly electrons, protons and alpha particles.
Where does solar wind come from
The suns corona
How fast is solar wind?
Hundreds of km per second
What does solar wind cause
Aroure
Why does solar wind cause aurora boreal is?
The charged particles spiral down the magnetic fields of the earth before hitting the atmosphere. Particles in the atmosphere then excite and de excite releasing photons.
Why is the magnetosphere stretched? (Magneto tail)
The force of the solar wind on the magnetosphere
What are van Allen belts?
Some of the plasma gets stuck trapped around the magnetosphere. We get belts of charged particles in space near the earth.