space physics- topic 6 Flashcards
how often does the earth spin in its axis
once every 24 h
how long does the earth take to orbit the sun
365 days
why do we experience seasons
his is because of the slight tilt of the Earth’s axis.
formula for orbital speed
2πr/ T
why does the moon shine
the Moon shines brightly because it reflects the light from the Sun
how long does the moon take to orbit the earth
a month
how is the earth tilted angle wise
23.5 degrees
why does the length of day vary
the tilt of the earth causes the length of night and day to vary according to latitude (north-south) location, and this changes throughout the year
what side of the moon faces the earth
the same side
what changes the phase of the moon we see
depends on the angle of the sun, the moon and the earth
what are planets
spheres of matter, orbiting the Sun
whats the order of the planets in the solar system
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune
describe each planet
mercury- small rocky planet
Venus- small rocky planet
earth- small rocky planet
Mars- small rocky planet
jupiter- gas giant planet
saturn- gas giant planet
uranus- gas giant planet
neptune- gas giant planet
dwarf planets
Small, rocky bodies orbiting the Sun, not big enough to be called planets. Pluto is an example.
asteroid belt
Millions of rocks, much smaller than planets, orbiting the Sun between Mars and Jupiter
comet
Balls of ice which orbit the Sun in elliptical orbits. When they come close to the Sun they heat up and some of the ice evaporates, becoming a visible tail.
what is a natural satellite
an object that orbits a planet or another body that is larger than itself
what are interstellar clouds
also known as nebulas, made from gas and dust all around the Universe and they are made from a variety of different elements
how did the solar system appear
dust from interstellar clouds clumped together beacuse of its own gravity, began to spin as a disc and eventually most ignited and became the sun.
particles in remaining disk combined by pull of gravity, these are the planets, called acretion model
most common elements in this acretion disk is hydrogen followed by helium, hydrogen and helium were pushed out and became giant gas planets, while iron became the rocky small planets close to the sun.
what is the relationship between mass, and gravitational field strength
The more mass an object has, the greater the gravitational field strength at its surface.
speed of light
3 x 10^8 m/s
equation for light to reach other planets
v= s/t
v=speed of light
s=distance light travels
t=time taken
what is the effect of distance on light and temperature intensity, and gravitational field strength
further away from the sun, less light intensity, weaker gravitational field strength
explain speed in eliptical orbits, and relationship
The planet moved faster during the part of the orbit where it was closest to the star
As the planet gets closer to the star, its gravitational potential energy is converted into kinetic energy – so it moves faster. As it travels away again, the kinetic energy is converted back into gravitational potential energy, so it slows down
when the orbital radius is greater, the planet moves more slowly,This is because the gravitational force of attraction from the Sun is weaker at these larger distances.
what is a star
a ball of gas which radiates energy in the form of electromagnetic waves.
but they are usually (unless they are dying) made of hydrogen and helium
what energy does our sun emit, does this vary between stars?
Our Sun emits most of its energy in the infrared, visible and ultraviolet regions of the electromagnetic spectrum (see subtopic 3.3). This can vary depending on the size and temperature of the star.