Origins of the Universe Flashcards
Can all explanations of the origins of the universe be explain scientifically?
No
What should scientific claims about the origins of the universe have?
They should be based on observations and should be tested
What is Newton’s first law of motion?
Every object in a state of uniform motion unless an external force is applied to it
What is Newton’s second law of motion?
The relationship between an object’s mass (m), and its acceleration (A)
What is the equation for Newton’s second law of motion?
force = mass x acceleration
What is Newton’s third law of motion?
For every action there is an equal and opposite reaction
What is Newton’s law of universal gravity?
Every mass attracts other masses in the universe with a gravitational force
Equation for Newton’s law of universal gravity?
F = G(m1m2 / r2)
Did everyone believe Newton’s laws?
No, people found small discrepancies between Newton’s laws and observed astronomical events
What’s the first problem that people found with Newton’s law of motion?
Mercury’s orbit did not follow Newton’s predictions
-Mercury’s elliptical orbit keeps on changing
What’s the second problem that people found with Newton’s law of motion?
Gravity can bend light
- During solar eclipses, a halo of light is seen around the moon
- It appears that light is bent around the moon due to gravity. However, light has no mass
What’s the third problem that people found with Newton’s law of motion?
Behaviour of spiral galaxies
-The rotation of stars around the centre of spiral galaxies do not obey Newton’s laws of motion and gravity
Did Albert Einstein agree with Newton’s ideas? Why/Why not?
No, he didn’t
- Einstein came up with his special theory of relativity
- The summary of this is that nothing in the universe can travel as fast as the speed of light
What did Newton predict about the Earth and how did this disprove his own theory?
Newton would predict that as soon as the sun disappears, the force grabbing the Earth would Instantly disappear too.
Therefore, the Earth would instantly move away due to Newton’s 1st law of motion
What is Einstein’s General Theory of Relativity?
Einstein proposed that 3 dimensional space is connected to time..
He imagined that the four things are woven into the fabric. He called this the four dimensional fabric of space-time
When happens when a large mass occupies a place in the space-time fabric?
It warps like a real fabric
Why is the warping of the space-time fabric crucial to our Earth?
Because it creates what we experience as gravity
Define how the earth orbits the sun in context to the warped space-time fabric
The Earth doesn’t orbit the sun because the sun reached out to the earth, but it simply follows the curved in the warp of space-time music
What happened when the General Theory of Relativity was first introduced?
It was a paradigm shift about how we think of gravity
As scientists how do we believe that the general theory of Relativity is a true concept?
- We have no proof that the speed of light is a constant.
- As far as we can tell, it seems to be true
- Because of the lack ofproof, we must remain skeptical
What are the three other measuring units that can be used?
- Astronomical unit
- Light Year
- Parsec
What is an astronomical unit?
Distance from the Earth to the Sun = 149,597,871,000m
What is a Light Year?
Distance it takes light to travel one Earth year in a vacuum =9,460,528,400,000,000m
What is a parsec?
=3.26 light years
What is Oblers Paradox?
In an infinite stars, the universe should be bathed in light. There shouldn’t be night and day.
However there is, therfore it is a paradox a
When did Edwin Hubble use one of the most powerful telescopes of his time?
1920s
What did Hubble discover using his telescope?
He discovered other galaxies existed
What method did Hubble use to determine how far these galaxies were from us?
The colour / brightness method
What did he notice about some of the light from these galaxies and what was the shift of colour due to?
He noticed that the light from some of these galaxies appeared more red than expected and this shift in colour was due to the doppler effect.
What does it mean if an object thats emits light is traveling away from you?
The wavelengths get stretched (i.e. longer / more red)
What does it mean if an object that emits light is traveling to you?
The wavelengths get squashed (i.e. shorter / more blue)
What did Hubble’s Doppler observations show?
That the universe is expanding
Who proposed the steady state theory?
Hoyle, Gold and Bondi
What are the 5 things that the Steady State Theory states?
- The universe is infinitely old
- It has no beginning and no end
- Hubble showed that the 3D dimensions of the universe is expanding
- Matter is slowly being made in the universe that forms new stars and galaxies
- The average density of the galaxies in the universe should remain constant
What does CMBR stand far?
Cosmic Microwave Background Radiation
What was compelling evidence for the big bang theory?
CMBR (Cosmic Microwave Background Radiation)
Why was the CMBR compelling evidence for the big bang theory?
- It was predicted to be there
- The calculated Doppler effect showed that the original light / temperature of the radiation agreed with models consistence with the big bang
- Nothing in the steady state theory accounted for it
What is the Expansion of the Universe?
It is such that each point in space is moving away from each other point in space, i.e. there is no specific starting point (Cosmological Principle)
What did Hubble discover?
Hubble’s law can be used to calculate the age of the Universe to 13.8 billion years (by extrapolating back in time)
How was the CMBR data was produced?
By COBE (Cosmetic Background Explorer) and WMAP satellites
How does the Big Bang Theory contradicts the first and second law of thermodynamics?
First law = ‘You can’t destroy or create matter or energy’
Second Law= ‘Things degenerate into disorder’
What’s the evidence that proves that the Big Bang Theory wasn’t the perfect explosion it is claimed to be?
If the Big Bang was a perfect explosion, every particle would be scattered away from each other. Therefore no galaxies / stars would be formed.
What is the definition of ‘dark matter’ ?
The galaxy has a lot more mass / matter than we can observe, hence the name dark matter.
What do galaxies of the universe appear to be?
Accelerating (they have greater velocities)
Which scientist believes that objects only accelerate if they are subject to a force (F=ma)?
Newton
What is the force pushing the galaxies making them accelerate?
We don’t know so we call it ‘dark energy’
