Module 1 - The Universe Flashcards
totality of all matter, energy and space.
Universe
is the study of how the universe begun, how it continues to exist and how it will end
Cosmology
Who proposed Big Bang theory or Big Bang model
George Lemaître and Edwin Hubble
The Big Bang refers to the very start of the whole process called the
Big Bang model.
The Big Bang was NOT an
explosion
The universe may have begun as an infinitely hot and dense initial _____, a point with all of space, time, matter and energy
singularity
All of it then began to rapidly expand in a process known as _____
Space itself expanded faster than the speed of light.
inflation
In this still hot and dense mass of the universe, pairs of ____ formed from energy, but these pairs cancelled each other back into energy ____
matter and antimatter (quarks and antiquarks)
(annihilation).
The universe cooled down as it expanded. An excess of matter (electrons, protons, neutrons and other particles) somehow came to be in a highly energetic “plasma soup.” Photons (light particles) were being scattered everywhere in this “soup”. Protons and neutrons came together to form different types of nuclei by nucleosynthesis or nuclear fusion.
…
The universe _____ as it expanded.
cooled down
An excess of matter (electrons, protons, neutrons and other particles) somehow came to be in a highly energetic
plasma soup
light particles
Photons
Protons and neutrons came together to form different types of nuclei by
nucleosynthesis or nuclear fusion
electrons started to bind to ionized protons and nuclei forming neutral atoms in a process called
recombination
The bound particles no longer scattered photons so light and energy moved freely across space.
Dark age
____ caused these atoms to collapse onto one another to form stars and galaxies and eventually, other matter.
Gravity
Space also continues to
expand at an accelerating rate, thus increasing the distance between the matters inside it.
Evidences of Big Bang
- Red shifts
- Cosmic microwave background
3.There is a H to He mass ratio of 3 to 1
distant galaxies Indicate the universe is expanding Wavelength of light waves increases Shifts to the red end of the spectrum Shows that galaxies are moving away from each other.
Redshifts
the wavelength from distant galaxies becomes much redder which proves that the space between us increase
Redder wavelength = longer wavelength.
Longer wavelength = the space between us and the distant galaxy is increasing.
Red shifts
microwave radiation that fills all space and is thought to represent the redshifted glow from Big Bang. Cosmic microwave background, or the energy (thermal radiation) that was left as a result of recombination.
Cosmic microwave background
It’s a faint glow of light that fills the entire universe, and it’s the leftover heat from the Big Bang
That first light, called CMB, has been traveling through the universe ever since. Over billions of years, as the universe expanded, the light got stretched into microwaves, which are lower-energy waves.
It’s like a faint “echo” of the Big Bang, and scientists can detect it using special telescopes.
Cosmic microwave background
When the universe expanded the first light it produced still existed, like a residual light, like an echo we hear from a loud sound
Cosmic microwave background
There is a ____ in the stars and interstellar material, as predicted by the Big Bang model. Protons and neutrons would routinely combine and separate from each other due to the high energies at the time.
H to He mass ratio of 3 to 1
Types of Nucleosynthesis
A. Primordial Nucleosynthesis or Big Bang nucleosynthesis
B. Stellar Nucleosynthesis
C. Super Nova Nucleosynthesis
D. Radioactive decay
Refers to the production of nuclei other than those of the lightest isotope of hydrogen (hydrogen-1, 1H, having a single proton as a nucleus) during the early phases of the Universe.
Primordial Nucleosynthesis or Big Bang nucleosynthesis
is the creation of chemical elements by nuclear fusion reactions within stars.
has occurred since the original creation of hydrogen, helium and lithium during the Big Bang
Stellar Nucleosynthesis
is the nucleosynthesis of chemical elements in supernova explosions.
Supernova nucleosynthesis
In sufficiently massive stars, the nucleosynthesis by fusion of lighter elements into heavier ones occurs during sequential hydrostatic burning processes called _____,
helium burning
Using the first three letters of the Greek alphabet. Some later time, alpha particles were identified as helium-4 nuclei, beta particles were identified as electrons, and gamma rays as a form of electromagnetic radiation like x-rays except much higher in energy and even more dangerous to living systems.
Radioactive decay
(High energy) helium nuclei consisting of two protons and two neutrons
Alpha particle
(High energy) Electron
Beta particle
Particles with the same mass as an electron but with 1 unit of positive charge
Positron
nuclei of hydrogen atoms
Proton
Particles with a mass approximately equal to that of a proton but with no charge
Neutron
Very high-energy electron
gamma ray
_____ is one process that unstable atoms can use to become more stable
an atom’s nucleus sheds two protons and two neutrons in a packet that scientists call an _____
Since an atom loses two protons during _____, it changes from one element to another.
alpha decay
Any of three processes of radioactive disintegration by which some unstable atomic nuclei spontaneously dissipate excess energy and undergo a change of one unit of positive charge without any change in mass number.
Beta decay
Usually accompanies alpha or beta decay. Gamma rays are photons and are without rest mass or charge.
Gamma decay
It is an observed fact that most of the matter in the universe are the three lightest elements:
These elements were present during the initial formation of the universe, with the heavier elements being later formed in massive stars.
hydrogen, helium, and lithium
_____, the temperature and density of the universe were appropriate for the efficient synthesis of the light elements.
first three minutes
Just as in the Sun, some of the hydrogen nuclei were underwent fusion to form heavier nuclei including helium nuclei. This was the era of
primordial nucleosynthesis
We know that the universe today contains about _____ of its mass in helium
23%
In fact, all the helium production in stars isn’t very important compared to the production in the _____ after the Big Bang
first three minutes
Big Bang nucleosynthesis produced very few nuclei of elements heavier than lithium due to a bottleneck: the absence of a stable nucleus with 8 or 5 nucleons.
Formation of Heavy Elements
_____ notes that it takes 100,000 years for the carbon to burn into oxygen, 10,000 years for the oxygen to burn into silicon, and one day for the silicon to burn into iron and herald the collapse of the star.
Physicist Lawrence Krauss
Astronomer _____ in the TV series “Cosmos” noted, “We are made of star-stuff.” Krauss agreed, stating that “every atom in your body was once inside a star that exploded.
Carl Sagan
