Fourth-Fifth Test Flashcards

Question

gestation times of different stars

Answer 1

100 solar mass stars born in 10k yrs, solar mass one million, 10^8 years for much smaller. they also die in related amounts of time.

Answer 2

cloud has some natural tendency to rotate. as gravity shrinks it, spins faster to conserve angular momentum. Horizontal force towards center, vertical force towards equator of spin: causes disk with packed middle. spirals up or down.

Answer 3

clouds of gas often form more than one star, many points of light. can form binary, tertiary stars, star clusters

Answer 4

one idea of how planets form. in cloud orbiting protostar, molecules stick together chemically. those then start sticking together gravitationally. kepler's third say that each little orbiting body orbits at different velocities, tug and stick to each other

Answer 5

maybe further accretion disks, maybe giant impact- he doesn't like this

Answer 6

1/12th solar mass

Answer 7

would be able to see core of sun, as light takes 10^5 years of reabsorption and emission to get out. use perchrolo ethylene with helium bubbling at first, that cannot detect all kind of neutrino, now look for light flashes in a pool of water, can detect all three. blurry map of sun made. deep underground to remove noise from other solar particles.

Answer 8

solar neutrinos detected did not match predictions not enough of them. Answered by neutrinos changing flavor as they travel, between electron, muon, and tao. before solution: sun's core off? black hole at center w/ sun sustained by rotation around it?

Answer 9

2H fuse into He2, then one more H to become He3, etc, double chains, get the slide.

Answer 10

4H -> 1He4 + 2 gamma rays + 2 positrons + 2 neutrinos

Answer 11

"little neutral ones". predicted 1930 when EM was not being conserved. Seen in 1942. Mass, not electric charge was missing, hence neutralness. almost impossible to detect, 10^13 through hand every second. half would survive ten lightyears of lead!

Answer 12

massive: red giant layers fall back in, process repeats of fusing heavier elements up to iron. iron is boundary between exothermic fusion and fission, no more fusing it. explodes in supernova maybe. smaller: stops burning helium, becomes size of earth but one solar mass, radiative heat, fades eventually to black dwarf.

Answer 13

10^0 - life of biggest star. 10^10 - life of sun 10^11 - life of bigs:moreth

Answer 14

solar neutrinos detected did not match predictions not enough of them. Answered by neutrinos changing flavor as they travel, between electron, muon, and tao.

Answer 15

South Dakota goldmine, super kumioandi in japan, IceCube array in antarctica

Answer 16

1844 serius B predicted from A wobbling, observed 1962, spec isolated 1915. problem: it was insanely dense!

Answer 17

1 solar mass, size of earth. 150lb person becomes 75 billion tons, AA battery (1/20lbs) becomes 250 million tons. one teaspoon of white dwarf material is 20 tons on earth. 1 mil grams/cm^3

Answer 18

Pauli Exclusion principle, heisenberg uncertainty principle. deltaX * deltaP > a constant. change in movement times change in momentum must remain greater than a certain constant. thus, as movement decreased, momentum increases, thus creating the quantum pressure needed to counter the force of gravity. "electron degenerate gas pressure"

Answer 19

10^0 - life of biggest star. 10^10 - life of sun 10^11 -

Answer 20

white dwarf. what happens to them?

Answer 21

old: clustered at bottom of HR, everything above has died. Lots of red giants shrinking to white dwarfs. in young cluster, lots of ones at top.

Answer 22

1844 serius B predicted from A wobbling, observed 1862. 1915 observed with spectral lines.

Answer 23

1 solar mass, size of earth. 150lb person becomes 75 billion tons, AA battery (1/20lbs) becomes 250 million tons. one teaspoon of white dwarf material is 20 tons on earth.

Answer 24

Pauli Exclusion principle, heisenberg uncertainty principle. deltaX * deltaP > a constant. change in movement times change in momentum must remain greater than a certain constant. thus, as movement decreased, momentum increases, thus creating the quantum pressure needed to counter

Answer 25

1.4 solar masses. after that, degenerate electron motion gets relativistic- can't hold up, no stability. developed 1930.

Answer 26

<1.4 solar masses. takes 2x age of universe for leftover heat to radiate away, becoming black dwarves, none exist yet.

Answer 27

light (photos) made in core from energy of fusion. because of density of interior of star, takes 10^5 (10,000) years to get out of the star. mathematically: a random walk. imagine drunk person leaving bar and taking one equal step at a time home. Math says that you WILL get there eventually. this is the path light follows as it is absorbed and re-emitted repeatedly.

Answer 28

spectral lines from a star broadened by properties such as temperature, rotation/turbulence (producing red and blue shifts). Using a densitometer, see darkness of spectral line. Each broadening effect has a different signature, use mathematical curves to remove these bit by bit- getting data from each time.

Answer 29

``` Temp ±50° gas pressure+density chemical abundances rotational velocity mag field strength+direction expanding gas shell radial velocity from earth ```

Answer 30

can red giants lose enough mass to become white dwarves? big stars have to lose 98.6% of their mass. in casting off outer layers, stars lose a ton but losing 90% is rare. thus, they become SOMETHING MORE

Answer 31

light appears to be leaving a nebula faster than light, its not, just geometry and different angles??

Answer 32

1967 PhD candidate under Anthony Hewish. Looking for an easy way to find quasars, which scintillate. Instead discovered radio pulses with regular period.

Answer 33

Bell told to go back to quasars! At first thought that pulsars were man made, then they started varying sidereal (4 min off) meaning they were outside solar system.

Answer 34

distance radio comes in as point source, narrow compared to cone-like planet. at the time, telescopes "integrate" radio signals, building them over time. This loses the pulsar data. Bell rented a field south of london built up-pointing antennas with 2x4s.

Answer 35

Fastly rotating main sequence with a hotspot- with period of one sec, would fall apart. Two binaries working together- speed required would mean they'd merge. white dwarfs also would fall apart.

Answer 36

rotating neutron star, left over after stellar explosion. size of burlington, 10km across. period of 1.3 millisecond to 10 seconds. .

Answer 37

a basic particle accelerator that synchronizes magnets with charged particles going around. researchers discovered that with a super-strong magnetic field, charged particles traveling at relativistic speeds emit blazes of light. a quantum effect, not a thermal emission

Answer 38

same as chand limit for white dwarves, but for neutron stars. limit is 1.4 (2 now) to five solar masses (upper limit). not sure how that bloody works! neutron stars only on small part of diagram.

Answer 39

collapsing stars >1.4 solar masses shrink past white dwarf density, pauli exclusion causes electrons and protons to fuse into neutrons. they find their own equilibrium like white dwarfs do = heisenberg delta x, delta p. "nucleon degenerate gas pressure"

Answer 40

150lbs Earth = 75 trillion trillion tons = 75*10^24 tons. | 1/20lbs Earth = 25 billion trillion tons + 25*10^21

Answer 41

super spinning neutron star. magnetic axis off slightly. off axis and rotation speed taken down from orig star when star collapses. atmosphere around it, slimmish jet from pole.

Answer 42

no pauli exclusion pressure on e- and p+ on outside of thing, they don't form neutrons strong magnetic field + relativistic speeds = SYCHROTRON EMISSION! as pulsar rotates, emitting part hits earth. width of emission cone is duration of pulse.

Answer 43

angular momentum goes down, some energy is radiated out by the jet. loses .000005 seconds in four years, measured by mean julian year- exactly 24hrs.