IB SL Physics Option D: Astrophysics

big bang theory

the universe began expanding from a point 13.7 Billion years ago

13.7 billion years

how long ago did the universe start expanding?

galaxy expansion/redshift

evidence 1 for the big bang theory

cosmic microwave background (CMB)

evidence 2 for the big bang theory

cmb

leftover heat from the “big bang” (peak intensity - microwave)

2.7 K

temperature of space due to cmb

lightyear (ly)

distance light would travel in a year in a vacuum

parsec (pc)

the distance of one arc second of parallax

parallax

the apparent motion of an object due to the motion of the observer

astronomical unit (AU)

the average distance from Earth to the sun

MVEMABJSUNKBOC

the order of the solar system

mercury Venus Earth mars

terrestrial

terrestrial

mercury Venus Earth mars are __________

jupiter saturn Uranus neptune

jovian

jovian

jupiter saturn Uranus neptune are __________

asteroid belt

between Mars and Jupiter

Kuiper belt

after neptune

ort cloud

after Kuiper belt

comet

has a highly elliptical orbit

nebula protostar main sequence red giant planetary nebula white dwarf black dwarf

life cycle for a star less than 8 SM (7 steps)

nebula protostar main sequence red giant red supergiant supernova neutron star

life cycle for a star greater than 8 SM (8-20 SM)

nebula protostar main sequence red giant red supergiant supernova black hole

life cycle for a star greater than 8 SM (20-80 SM)

nebula protostar main sequence red giant red supergiant supernova supermassive black hole

life cycle for a star greater than 8 SM (80+ SM)

1) nebula

collection of gas and dust

2) protostar

spherical, but no fusion

3) main sequence

all fusing H (hydrogen) (our star)

4) red giant

fusing non-H elements up to Fe

5) planetary nebula

after red giant, if less than 8 SM

6) white dwarf

after planetary nebula (less than 8 SM)

7) black dwarf

after white dwarf (not yet observed) (less than 8 SM)

5) red supergiant

after red giant (greater than 8 SM)

6) supernova

after red supergiant (greater than 8 SM)

7) neutron star

after supernova (8-20 SM)

7) black hole

after supernova (20-80 SM)

7) supermassive black hole

after supernova (80+ SM)

radar

shoot light, see how long it takes to bounce back (solar system)

parallax

two known distances, two different points of the year, find the angle

spectroscopic parallax

looking at two stars where the wavelength has shifted, redshift of stars

cepheid variable

solve for distance - b = L/4pir²

type 1a supernovae

occurs at a known luminosity, use equation to solve for distance

Hubble’s constant

redshift of galaxies (H_⁰)

planet

a celestial body that orbits a star

single star

a luminous sphere of plasma held together by its own gravityb

binary star

two stars orbiting a common center

planetary system

gravitationally bounded non-stellar objects in orbit around a star or star system

constellation

a pattern of stars visible from Earth that are not gravitationally bounded

stellar clusters

a group of stars gravitationally bounded together

nebula

the ejected envelope of a red giant star

galaxy

stars, gas, and dust held together by gravitational forces

clusters of galaxies

two or more galaxies that are close enough to each other to affect each other through gravitation