Red Shift (8.2) (M) Flashcards
What is observed from the most distant galaxies?
an observed increase in the wavelength of light
What is red shift?
An observed increase in the wavelength of light from (distant) galaxies
What does red-shift suggest?
The further away the galaxies, the faster they are moving due to the bigger the observed increase in wavelength
What does an observed increase in wavelength (i.e. red shift) mean on the electromagnetic spectrum?
Dark lines that appear, representing wavelengths absorbed from elements in Sun, shift to red end of electromagnetic spectrum
2 things
What does red-shift provide evidence for?
The observed red-shift provides evidence that space itself (the universe) is expanding and supports the Big Bang theory
What does the Big Bang Theory suggest?
that the universe began from a very small region that was extremely hot and dense
What provides evidence that distant galaxies are receding ever faster? i.e. acceleration away from us
observations of supernovae from 1998 onwards
What do observations of supernovae from 1998 onwards suggest?
distant galaxies are receding ever faster
The change of each galaxy’s speed with distance is evidence of what?
an (ever) expanding universe
What led to the development of the Big Bang Theory?
Red-Shift
How does red shift provide evidence for the Big Bang model?
Red shift proves that the further away the galaxies, the faster they are moving because of the bigger red shift/observed increase in wavelength (shift to red end of electromagnetic spectrum)
Therefore the universe must have began from a very small region that was extremely hot and dense
What is CMBR?
the remains of the thermal energy from the Big Bang, which is spread thinly across the whole Universe
How does CMBR provide evidence for the Big Bang?
The Bg Bang theory suggests that Initial heat from the Big Bang should now be thinly spread across the whole Universe
CMBR is detected at a very low temperature
This was discovered after the Big Bang Theory was developed (so provided very strong evidence)
There is still much about the universe that is…
not understood
2 needed
What are some components of the universe that are not understood that much?
Dark mass (matter) and dark energy
What is dark energy?
An unknown form of energy, put forward as a solution to the problem of why the expansion of the Universe is accelerating
makes up 68% of universe
What is dark mass (matter)?
An unidentified form of matter that accounts for galaxies rotating faster than their visible mass should cause
makes up 27% of universe
Galaxies seem to rotate too (…) for the mass of their stars
quickly
What do galaxies rotating too quickly for their mass suggest? How do they know this?
That there is mass in the Universe that is invisible to the instruments used by scientists.
Scientists only know it is there because it has gravity that affects objects nearby
What is blue-shift?
A decrease in the wavelength of light observed from a galaxy
What does blue-shift suggest?
The galaxy is moving towards us
What are the main ideas of the big bang?
all matter concentrated at single point
single massive explosion sent matter outwards
make sure to mention definition above these points
The Big Bang is one way of explain the (…) of the universe
origin
Give one strength and one weakness of this method to represent the idea of an expanding universe.
Strength: as balloon expands, the dots get farther away representing galaxies moving apart
Weakness: there is a limit to how far the balloon can expand (or dots on only surface, galaxies throughout universe)
