GGR100H1 Lecture : Glaciers, The Ice Age & Paleovegetation pkg. Lectures from March 17th and 22nd, Including the three broad topics in the title and all their subdivisions.

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emeraldbutterfly273

16 Oct 2011

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Agents of erosion: wind/water/ice act to transport materials that"ve been loosened by physical/chemical weathering and mass wasting. Ice: pwrful aoerosion b/c can move massive amnts. of sediment. > glacial: significant area of earth covered in ice; much glacial erosion potential. Greenland/mountains/arctic , but ice is still available in high latitudes/elevations. Large mass of flowing land ice; plastic body that flows. Ice on land under pressure begins to flow, becoming a glacier. Mass balance: glacier fed (accumulates) from precipitation in form of snow at the top, and ablates (melts) at the bottom. > can"t form in dry, high temperature areas. >glaciers form in conditions of low temperature and adequate snowfall/ppt. > in certain areas, snowfall from winter doesn"t melt in summer and continues to accumulate. Persisting snow is compacted over time into glacial ice (firn), due to intense pressure from the heaviness of piling precipitation.

Related Questions

19. The interstellar medium has a cool component measuredvia_________ observations and a hot component revealed by________observations.
AX-ray; optical
BX-ray; infrared
CX-ray;gamma-ray
Doptical; X-ray
Einfrared; X-ray

20. Which of the following processes will NOT cause a gas cloudtocollapse?
Aionization from youngstars
Bsupernovaexplosions
Cgalacticrotation
Dthe expansion of theUniverse

21. What is responsible for emitting photons in anemissionnebula?
Aexcitedprotons
Bexcitedneutrons
Cexcitedelectrons
Dexcitedneutrinos
Eexcitedastronomers

22. White dwarf stars are supported from collapse by
Anuclear fusionreactions in a shell around the core.
Belectron degeneracypressure.
Cnuclear fusion reactionsin their cores.
Dcentrifugal force due torapid rotation.

23. The "star" that is seen at the center of a planetarynebulais
Aa planet in theprocess of formation.
Ba small, hot, and verydense, white dwarf star.
Cthe accretion disk arounda black hole.
Dcomposed almost entirelyof neutrons, and is spinning rapidly.

24. A white dwarf star, the surviving core of a low-massstartowards the end of its life, can be found ontheHertzsprung-Russell diagram
Aat the bottom end ofthe main sequence, along which it has evolvedthroughout itslife.
Babove and to the right ofthe main sequence, since it evolved thereafter itshydrogen-burning phase.
Cbelow and to the left ofthe main sequence.
Dat the upper left end ofthe main sequence, since its surfacetemperature is extremelyhigh.

25. The mechanism which gives rise to the phenomenon of thenovais
Amaterial fallinginto a black hole and being condensed to the pointwhere athermonuclear explosion is produced.
Bthe impact and subsequentexplosion of a large comet nucleus upon astar's surface.
Cthe completedisintegration of a massive star because ofthermonuclear runawayin the star's interior.
Dmatter from a companionstar falling onto a white dwarf in a closebinary system,eventually causing a nuclear explosion on thedwarf'ssurface.

20. Which of the following processes will NOT cause a gas cloudtocollapse?
Aionization from youngstars
Bsupernovaexplosions
Cgalacticrotation
Dthe expansion of theUniverse

21. What is responsible for emitting photons in anemissionnebula?
Aexcitedprotons
Bexcitedneutrons
Cexcitedelectrons
Dexcitedneutrinos
Eexcitedastronomers

1. The Jeans instability occurs when
Athe pressure in a gascloud is less than its gravitationalforce.
Bthe pressure in a gascloud is greater than its gravitationalforce.
Cthe temperature in acollapsing cloud is hot enough to fuseHydrogen.
Dthe temperature in acollapsing cloud is hot enough to fuse Helium.

2. At what stage in its life does a star pass through theprotostarphase?
AAfter condensationbut before nuclear reactions begin in itscore.
BWhile it is convertinghydrogen into helium in its core.
CAfter nuclear reactionsend in its core, but before the red giantphase.
DWhen it is expanding insize as a red giant or supergiant.

3. The characteristics of an open cluster of stars are
Aa few hundredmembers, often very young and still embedded in thegas and dustfrom which they were formed.
Bmany thousand members, ofdifferent ages.
Ca few dozen members, theremnant of a globular cluster of starsfrom which most of themembers have escaped.
Dhundreds of thousands ofmembers, all very old, and no or verylittle interstellar gas anddust.

4. What is a protostar?
AA star near the endof its life, before it explodes as asupernova.
BA sphere of gas aftercollapse from an interstellar cloud butbefore nuclear reactionshave begun.
CA small interstellarcloud, before it collapses to become astar.
DA shell of gas left behindfrom the explosion of a star as asupernova.

5. What is an H II region?
AA region of hot,ionized hydrogen around one or more O and Bstars.
BA region of molecularhydrogen inside a giant molecularcloud.
CA region of neutral,atomic hydrogen in interstellar space.
DA region of gas and dustformed by the explosion of a massive star.

6. The total time that the Sun will spend as a main sequencestaris
Aabout 4.5 millionyears.
Bat least 200 billion yearsyears.
Cabout 1 millionyears.
Dabout 10 billionyears.

7. How is a star's lifetime related to its mass?
AThe lifetimes ofstars are too long to measure, so it is not knownhow (or if) theirlifetimes depend on mass.
BA star's lifetime does notdepend on its mass.
CLower-mass stars runthrough their lives faster and have shorterlifetimes.
DHigher-mass stars runthrough their lives faster and have shorterlifetimes.

8. In the Hertzsprung-Russell diagram, how does the position ofatypical star change while it is at the main sequence phase ofitsevolution?
AA star's position onthe main sequence is determined only by itsmass and not its age,and so, stars do not move along the mainsequence duringevolution.
BMassive stars (4 solarmasses) move toward the upper left as theirluminosity increases,while lower-mass stars move toward the lowerright as theirtemperature decreases.
CStars move from upperright to lower left while they are on themain sequence.
DStars move from upper leftto lower right while they are on themain sequence.

9. Why does the core of the Sun contain more helium andlesshydrogen than does the surface of the Sun?
AHelium condenses moreeasily so, when the Sun was forming the corebecame helium-rich;vast quantities of hydrogen were added onlyafter the core becamemassive enough.
BThe hydrogen has beenlifted out of the core by the Sun's magneticfield.
CHelium is heavier thanhydrogen, and has sunk toward the center ina process of chemicaldifferentiation.
DThermonuclear reactionshave converted much of the originalhydrogen in the core intohelium.

10. In terms of nuclear reactions, what is the next stage ofastar's life after the end of hydrogen burning in thecore?
AHydrogen burning ina thin shell around the core.
BHelium burning in thecore.
CCarbon burning.
DDeath (it becomes eithera supernova or a white dwarf).

GGR100H1 Lecture : Glaciers, The Ice Age & Paleovegetation pkg. Lectures from March 17th and 22nd, Including the three broad topics in the title and all their subdivisions.

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