Chapter 7 Flashcards
Why does our weight change depending on what planet we are on?
The weight of an object is the force acting on it due to gravity. Your mass doesn’t change however on different planets our weight changes eg- mars has less gravity than earth so you would weigh much lighter there.
What does our solar system consist of?
A sun (our star) eight planets and their natural satellites (such as our moon), dwarf planets, asteroids and comets.
Recall the name and order of planets in terms of distance from sun.
My Very Educated Mother Just Served Us Noodles
Start from closest to the sun- Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune
How have our ideas about the structure of the solar system changed over time?
We use to believe the geocentric model but now believe the heliocentric one
What is Geocentric and Heliocentric?
Geocentric is an earth centered model and Heliocentric is Sun centered model
Describe the orbits of moons, planets, comets and artificial satellites
Moons- rounder
Comets- elliptical orbit
When something has a circular orbit, how does the force of gravity lead to changing velocity of a planet without changing speed?
Objects orbiting the earth, those closer to the earths surface would travel faster because the gravity is stronger so it needs to travel fast enough to avoid hitting the earths surface
What is an orbital period
Time it takes for an astronomical object to complete one orbit around another. The orbital period of a planet depends upon its distance from the sun. The further away an object is from the sun, the longer its orbital period because there is a weaker gravitational force of attraction between it and the Sun.
What is an object doing when its orbitting
Constantly falling but never hitting the ground
Compare the steady state and big bang theories
The steady state theory suggests that as the universe expands new matter is created, so the overall appearance of the universe never changes-Fred Hoyle.
The big bang however suggests that 13.7 billion years ago the universe was concentrated into a single incredibly tiny point. This began to enlarge rapidly into a hot explosion, the universe is still expanding today.
What evidence is there to support the big bang theory
Red shift- If a source of light is moving away from us, the wavelength will appear to increase. The light will appear redder and cosmic microwave background radiation (cmb)-remains of energy created just after the Big Bang
Which theory is there more evidence for?
there is more evidence supporting the Big Bang
theory than the Steady State theory, it is the currently
accepted model for the origin of the Universe
What is the Doppler effect?
If a source of waves is moving relative to an observer, the observed wavelength and frequency will change.
Give an example of train for the Doppler effect and further explain the scenario
As a train moves towards the observer, the waves are pushed together reducing their wavelengths. That means that the frequency increases and the sound will get higher pitch.
Describe the red-shift in light received from galaxies at different distances away form the earth.
How does this provide evidence for the universe expanding
The further from us a star is, the more its light is red-shifted. This tells us that distant galaxies are moving away from us, and that the further away a galaxy is, the faster it’s moving away. THEREFORE IS EVIDENCE THE UNIVERSE IS EXPANDING
How do both the big bang and steady state theory account for red-shift of galaxies.
X
Explain how the discovery of the CMB radiation led to the Big
Bang theory becoming the currently accepted model
Cosmic microwave background radiation is evidence for the big bang theory only. This discovery has led to there being more evidence for this theory and therefore being the currently accepted model.
The evolution of stars is similar to what? Explain the steps
The evolution of stars is of similar mass to the sun through the following stages- Nebula Star (main sequence) Red giant White dwarf
