12 - Current Scientific Cosmology

Question 1

a branch of astronomical science that focuses on where everything came from (origin + development of the universe)

Answer 1

cosmology

Question 1

places the universe timeline of events on a 12 month calendar (13.89Gy). In the last 30 seconds of this calendar, humanity was created

Answer 1

cosmic calendar

Question 2

everything that exists

Answer 2

the universe

Question 3

a portion of the universe that can be seen from your location in space/time (finite)

Answer 3

observable universe

Question 4

time in years equal to the distance of the object in light years, ex to the moon its 1.3 seconds, sun is 8 mins, nearest star is 4 years from earth

Answer 4

look-back time

Question 5

In theory, with the amount of stars we have in the universe, the night sky should be bright, but the night sky is not bright, and is mostly dark! What is this paradox called and what is its solution?

Answer 5

Olbers’ Theory
A. the most distant stars are so far away that light from them hasn’t reached earth. that’s why the night sky is dark because the universe had a beginning

Question 6

galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving away from Earth

Answer 6

Hubble Law

Question 7

The universe’s expansion rate

Answer 7

Hubble Constant

Question 8

provides an estimate of the age of the universe based on the current rate of expansion. this helps us figure out the universe’s age (14 GY)

Answer 8

hubble time

Question 9

radiation of hot matter of universe soon after big bang, found by accident. It’s a low hum from the birth of the universe

Answer 9

Cosmic Microwave Background (CMB)

Question 10

universe matter + energy compressed into a high-density, high-temperature state

Answer 10

big bang

Question 11

What are the four steps of the Big Bang?

Answer 11

1. Inflation (exponential expansion of space/time)
2. Hot Big Bang (radiation, nucleosynthesis)
3. Recombination (dark age where nothing happens, continuation of expansion in darkness)
4. Reionization (first stars, light - it’s bright again)

Question 12

Isotropy (same observable properties) + Homogeneity (matter is uniformly spread) =

Answer 12

Cosmological Principle

observer in any galaxy sees the same general universe, the same general properties, minor local and evolutionary variations, no centre or edge.

provide a basis for the assumption that the physical laws that govern the universe are the same everywhere and in every direction on a large scale.

Question 13

phenomenon in which the light emitted by objects in the universe appears to be shifted toward longer wavelengths, specifically toward the red end of the electromagnetic spectrum.

Answer 13

cosmic red shift

Question 14

what are three models of the universe?

Answer 14

1. open universe: space-time curved in, the universe is infinite
2. closed universe: space time is curved to meet itself, finite universe
3. space-time is not curved and grows forever

Question 15

refers to the density of matter and energy required for the universe to be exactly flat on cosmological scales. It plays a crucial role in determining the overall geometry and fate of the universe.

Answer 15

critical density

Question 16

proposed dark matter particles other than protons and neutrons. It’s a mystery. Recent models suggest cold dark matter (made of slow moving particles)

Answer 16

Nonbaryonic matter

Question 17

why was the universe so close to exactly flat with no space-time curvature, at the time of the big bang?

Answer 17

flatness problem

Question 18

how did every part of the observable universe get to be so nearly the same temperature by the time of recombination?

Answer 18

Horizon Problem

Question 19

a solution that says there was an extra expansion in the big bang, where a very young universe expanded and cooled

Answer 19

inflationary big bang

Question 20

Einstein added to space-time equations representing force of repulsion modern astronomers believe drives acceleration

Answer 20

cosmological constant

Question 21

energy driving universe expansion acceleration

Answer 21

dark energy

Question 22

if dark energy increases with time, expansion acceleration shred galaxies, stars, and atoms

Answer 22

big rip

Question 23

distribution of superclusters in filaments of walls enclosing voids, the Sloan Great Wall is the largest known structure in the universe and it is 1.4 billion LY long

Answer 23

large-scale structure