Topic 1 Flashcards
Law?
A logical relationship between two or more things. Often mathematical
Hypothesis?
An educated guess, “if/then”, testable prediction
Theory?
An explanation for why certain laws and facts exist. It can be tested to determine its accuracy.
Belief?
A statement that is not scientifically provable in the same way facts and laws are. Scientifically disproven beliefs can still be held to be true
Opinion?
Belief based on observation
Constellation?
Grid like segment of stars in the sky; older definition was a group of stars that appear to form a pattern
Transit of Venus?
When planet Venus crosses in front of the sun (happens in pairs 8 yrs apart every 120 years)
Galaxies?
Huge collection of stars held together by their own gravity
Big Bang theory?
Theory that the universe began from a hot, dense state at some time in the past, from when it has continued to expand and will continue to do so in the future (Hubble)
Steady State Theory?
Theory that the Universe has always existed and that matter is constantly being created at an enormous rate, causing the Universe to expand (Fred Hoyle)
Explain what Hubble achieved, his work
1929, discovered that the spectra of light from galaxies inferred that they were moving away from Earth also found the further away galaxies were from Earth, the faster they were moving-space is expanding and taking galaxies with it. Galaxies are racing away from each other so everything must of come from the same spot, as if the universe was born from some sort of explosion.led to Big Bang.
Explain Fred Hoyles work
Steady state theory, universe has always existed and always will, universe expanding due to mass matter production.
What is evidence for the Big Bang theory?
Big Bang relied on existence of some sort of radiation-the fading heat from the formation of the Universe at the time of a huge event. They found this evidence in 1965, Penzias & Wilson found strong background noise whilst using sensitive radio telescope antenna- it was found to be a form of electromagnetic radiation known as cosmic microwave background (CMB) radiation
What is CMB?
Form of electromagnetic radiation in the microwave spectrum left over from the formation of the Universe, it is evidence for the Big Bang theory
What do dark bands represent ?
Absorption spectra
What do bright bands represent?
Emission spectra
Emission spectrum?
Pattern of wavelengths (or frequencies) that appear as coloured lines in a spectroscope; it is unique to each element
Absorption spectrum?
Spectrum with lines missing from the pattern; opposite of an emission spectrum because the element has absorbed its characteristic light wavelengths and removed them from the spectrum
How big is the universe?
Humans can’t even begin to understand how massive it is
Explain what a shorter wave means?
More energy, higher frequency and violet light
Explain longer waves
Less energy, lower frequency, red light
What is the Doppler effect?
If something is moving towards you it looks bluer (shorter and compressed waves). If something is moving away from you it looks redder (longer waves). Red= red shift. Blue= blue shift.
What will happen to our universe?
A) will keep expanding forever, everything will get colder, darker and further apart
B) it will stop expanding and start contracting, collapsing back in on itself (Big Crunch)
C) will reach a maximum position and stop
Problems with the Big Bang? Dark matter?
There is not enough matter (stuff) in universe to account for the strength of the gravity in and between galaxies- scientist came up with dark matter/energy (E=mc^2)- it’s there but we can’t see it or detect it, makes up 95% of universe.
Difference between astrology and astronomy?
Astronomy- studying the universe and its contents outside the earths atmosphere
Astrology- how the positions and motions in the universe effect people and events on earth
How do galaxies and planets form?
Form over billions of years as gravity draws matter together
What rate is matter produced per second?
10^32kg
Open universe?
Extends infinitely far in every direction and will continue to expand forever
Closed universe?
The gravity stops expansion from contracting, the closed universe is cold, dark and lifeless
Flat universe?
Is squeezed into a single point, it will stop expanding but not contracting.
Where do atoms come from that make the raw materials on earth?
The Big Bang and through evolution of the universe
Why didn’t electrons form bonds?
Too much heat and energy for the electrons to form bonds
When did the first atomic nuclei form? And conditions needed
When expanding cosmos cooled sufficiently, protons and neutrons binded together and formed first ones.
When did first atoms form? Conditions?
380000yrs after Big Bang temp had dropped and electrons began to slow down and form first true atoms.
What did the cracks in the baby universe become?
Galaxies and stars