Week 1: How the elements are formed Flashcards
Explain the big bang theory
The best-supported theory of our universe’s origin centers on an event known as the big bang. This theory was born of the observation that other galaxies are moving away from our own at great speed in all directions, as if they had all been propelled by an ancient explosive force.
Who suggested the big bang theory?
Georges Lemaître
By mass, hydrogen was how many percent of the early universe’s matter?
75%
By mass, hydrogen was how many percent of the early universe’s matter?
25%
What does cosmic microwave radiation indicate ?
it indicates that the big bang actually happened because it is the oldest radiation known and may hold many secrets about the universe’s earliest moments.
Who discovered cosmic microwave radiation?
It was first predicted by Ralph Alpherin
What evidence is there that the universe began in a big bang?
the tiny bit of background radiation in the universe is energy remaining from big bang is evidence that the universe did begin in a big bang
What happened in the first minutes after the Big Bang?
After only a few seconds, protons, neutrons, and electrons formed
Everything that is now in the universe was squeezed into a very small volume called a ____
singularity
What is a cloud of gas and dust?
nebula
How do stars form?
Stars form in a nebula
Why do scientists think the Pillars of Creation are where stars are forming?
Because in the Pillars of Creation, gas and dust come together as a stellar nursery
What is building up of heavier nuclei called ?
Nuclear fusion
Three important fusion processes are:
Proton-proton chain, CNO cycle and triple alpha process
Proton-proton chain
details how helium is made in our sun
CNO cycle
explains how hydrogen is fused in hotter stars
Triple alpha process
accounts for the helium fusing that occurs in mature stars
Once all the hydrogen in the core has been used up, helium is fused into ?
carbon, nitrogen and oxygen
After helium fusing ends in high mass stars, carbon fusing begins creating ?
oxygen, neon, sodium, and magnesium.
a star having a mass of more than 8 solar masses
supergiant
Some of the reactions which lead to the creation of these new elements also produce ?
neutrons
These neutrons arecaptured by some of the new atoms to form different ?
isotopes
the fantastic death of supergiant stars
supernovae
Where are the heaviest elements created in?
supernovae
What percentage of stars are binary?
70%
What was present after the big bang?
the first four elements
Which elements were created in red giants?
elements up thru magnesium
Which elements were created in supergiants?
elements up thru iron
Which elements were created in supernovae?
elements from iron to uranium
When atoms meet one another in nebulae, what happens?
chemical reactions take place
