Waves and the Universe Flashcards
Compare the relative sizes of between the
Earth, the Moon, the planets, the Sun, galaxies and the Universe
If:
Earth = 1
Moon = 0.25
Planets = range 0.4 to 11
Sun= 100
Galaxy = 10 trillion
Universe = n/a
Compare the distances between the
Earth, the Moon, the planets, the Sun, galaxies and the Universe
Earth - Moon = 3x108 m
Sun - Earth = 1.5x1011 m
Nearest Star = 4x1016 m
Galaxy = 2x1022 m
Universe = n/a
What are the benefits of the modern day telescopes?
- Better magnification causes clearer images
- ABility to detect different regions of EM spectrum allows images to be take that would otherwise be invisible (e.g. star formations)
- A computer is conneceted to the telescope making the image quality better as exposure time can be very long.
Why do scientists send telescopes into space?
- Clearer and Sharper images. This is because it excludes the relection, refraction and scattering of light.
- The atmosphere absorbs certain wavelengths.
How have space probes been used to look for aliens in the solar system?
- It can sample the soil and find out what it’s made of and send results back to earth (including looking for micro-organisms).
- It can take images.
Space probes have found that there was water on Mars using the above 2 methods.
Have any discoveries been made beyond the solar system?
Planets beyond the solar system are too far away to photograph. However, scientists can detect what gasses are present in planets beyond the solar system, and can use this to look for signs of life (oxygen).
What is SETI?
Search for Extra Terrestrial Intelligence is a series of projects that analyse radio waves coming from space looking for signals sent by aliens.
What is a spectrometer?
It is a device that can split up the different wavelengths of light into a spectrum.
How can a spectrometer be used to investigate the gasses present in the sun?
The sun generates light across the visible spectrum, but when a spectrum is taken of sunlight reaching Earth there are gaps, this is because of gasses in the sun that absorb these wavelengths therefore not reaching the spectrometer.
Why would the spectrum of sunlight taken by a spectrometer within the Earth’s atmosphere be different to a spectrum taken by a spectrometer in space.
There aren’t any gasses to absorb the light.
Describe the evolution of stars of similar mass to the Sun
through its stages.
- nebula- Dust and hydrogen is pulled together due to gravity.
- star (main sequence)- Eventually the temperature gets hot enough to allow fusion of H2 to He. The EM radiation given out from fusion is now balanced with the gravity pulling it in and therefore it enters a stable period.
- red giant- H2 begins to run out therefore gravity begins to crush the core what remains on the outside is lots of gas.
- white dwarf - Once all fusion reaction have stopped.
- Black Dwarf- Once the star has cooled down.
Describe the evolution of stars bigger than the sun.
- All the same until you get to red giant where it becomes a red super giant.
- Instead of becoming a white dwarf in explodes into supernova
- If what is left is 4 to 5 times bigger than the sun it turns into a black hole otherwise it become a very dense star called a neutron star.
What are the similarities and differences between steady state and the big bang theory?
Steady State Theory
Big Bang Theory
No beginning, No end
Is a beginning
Universe expands due to creation of new matter
Expands due to big bang push apart matter
Evidence
Red shift
Red shift and Cosmic Microwave Background Information (CMB)
What is the doppler effect?
As a source of waves moves away from the observer the wavelengths detected get longer
What is Red Shift?
The spectrum of light from distant galaxies is almost identical to that of the sun, except that it is shifted towards the red i.e. all detected wavelengths are slightly larfger than those seen for spectrum of sun.
