The document discusses the formation of the solar system from a molecular cloud. It describes how:
1) The cloud collapsed due to gravity, forming a hot solar nebula with a temperature gradient.
2) Atoms condensed into microscopic particles in different regions based on temperature, then accreted into planetesimals.
3) Terrestrial planetesimals grew into protoplanets through collisions, then differentiated into cores and mantles.
4) Jovian protoplanets captured gas and ice from the nebula through gravitational collapse, forming large atmospheres.
Overview talk about NASA's LCROSS Mission that provided an impact experiment to search for water within a permanently shadowed region at the lunar pole. Secondary payload, low cost, active risk management, successful. Mission ended Oct 9, 2009. The "impact" of the impact is rewriting science and exploration of our nearest neighbour.
The international Cassini-Huygens spacecraft was launched on October 15, 1997 and had a marathon 7-year 2-billion mile journey to the distant planet Saturn. The 23-foot tall, 14-foot wide, 6-ton spacecraft is the largest most sophisticated outer planet spacecraft ever built, and is in its third year of operation in orbit around the planet Saturn. Cassini-Huygens has been returning extraordinary data about the entire Saturn system: the spectacular rings; the numerous icy satellites with a variety of unique surface features; the giant planet itself; a huge magneto-sphere teeming with particles that interact with the rings and moons; and the intriguing moon Titan, which is slightly larger than the planet Mercury, and whose hazy atmosphere is denser than that of Earth. This talk will be an overview of the Cassini-Huygens mission to Saturn with a summary of the top science returns of its first three years in orbit.
The Minnesota Space Grant Consortium, run out of the Department of Aerospace Engineering and Mechanics at the University of Minnesota, hosts Trina Ray of NASA JPL on January 22, 2008.
Overview talk about NASA's LCROSS Mission that provided an impact experiment to search for water within a permanently shadowed region at the lunar pole. Secondary payload, low cost, active risk management, successful. Mission ended Oct 9, 2009. The "impact" of the impact is rewriting science and exploration of our nearest neighbour.
The international Cassini-Huygens spacecraft was launched on October 15, 1997 and had a marathon 7-year 2-billion mile journey to the distant planet Saturn. The 23-foot tall, 14-foot wide, 6-ton spacecraft is the largest most sophisticated outer planet spacecraft ever built, and is in its third year of operation in orbit around the planet Saturn. Cassini-Huygens has been returning extraordinary data about the entire Saturn system: the spectacular rings; the numerous icy satellites with a variety of unique surface features; the giant planet itself; a huge magneto-sphere teeming with particles that interact with the rings and moons; and the intriguing moon Titan, which is slightly larger than the planet Mercury, and whose hazy atmosphere is denser than that of Earth. This talk will be an overview of the Cassini-Huygens mission to Saturn with a summary of the top science returns of its first three years in orbit.
The Minnesota Space Grant Consortium, run out of the Department of Aerospace Engineering and Mechanics at the University of Minnesota, hosts Trina Ray of NASA JPL on January 22, 2008.
1) describe how temperature influenced what materials condensed from t.docxjbarbara1
1) describe how temperature influenced what materials condensed from the nebular cloud.
2) compare and contrast the composition of the inner and outer planets
3) explain the frost line and the influence it has on the formation of planets (in any solar system).
4) explain why our solar system has rocky inner planets and gaseous outer planets and identify the most metal-rich planet in the solar system
5) explain the occurrence of Hot Jupiters
Solution
Solution:
1) During the early stage of evolution , soon after the completion of the cloud collapse , nebula is hot . The mass accretion rate from the nebula onto the star is high . The equilibrium condensation temperature of the Silicates and metal comprises 90 % (by mass) of the condensable solids.The temperature decreases away from the mid plane and away from the Sun. The accretion of gas onto the sun leads to the dissipation of energy . The nebula is heated internally due to this .
Condensation metals include Iron , Nickel and Aluminum . Most metals condense into solids at temperatures of 1000 - 1600 K . Metals made up <0.2% of the Nebular mass.
2) The Inner planets are Mercury , Venus ,Earth and Mars. They are all solid and rocky and similar to Earth . Inner Planets are also called Terrestrial Planets . Inner planets are warmer as these are closer to Sun .
Outer planets are called Jovian Planets and are mainly Gaseous in nature . Outer planets are colder as they are farther away from the Sun. All Outer planets have rings .
3) Frost line is also called the Snow line or Ice line . It is the radial position of condensation or evaporation front which varies over time . With reference to the formation of the planets, it is the distance in the Solar Nebula from the central protostar where it is very cold to where the volatile compounds like water , Ammonia , CO2 ,CO condense into solid ice grains.
4) The temperature of the early solar system explains the Terrestrial nature of the inner planets . As the gases coalesced to form the proto Sun the temperature in the inner SOlar system rose . The temperatures rose to about 2000 K , so only substance which have very high melting points remained solid . That is why the inner solar system planets are all rocky .
5) Planetary migration is responsible for the formation of hot Jupiters. These are formed in the outer regions and then migrate to the inner regions of the Solar system . It forms beyond the frost line , from rock , ice and gases due to core accretion method of planetary formation .
.
Theory of Planetary System Formation The mass of the presol.pdfadislifestyle
Theory of Planetary System Formation The mass of the pre-solar molecular cloud played the
largest role in terms of how the solar system formed. It might have begun with a 100 solar mass
cloud approximately 1 to 2 light years in diameter. It's possible that mutual gravitational attraction
between cloud particles was too weak to start the process. When gravity is too weak, the only
other force strong enough to bring a significant number of particles together is the electromagnetic
force. Barring that, perhaps a nearby shockwave from a supernova explosion caused the initial
motion of material: but once started, gravity took hold, causing the inevitable collapse. The
process it underwent followed a pattern that scientists believe is mirrored everywhere a star exists.
In this activity, you will put the solar system formation process parts in order from the beginning. 1.
Planetesimals accreted material until they became large enough to form planets. 2. Gravitational
potential energy of the collapsing gas cloud was converted into thermal energy. 3. Collapsing gas
cloud rotated faster as the collapse continued due to conservation of angular momentum. 4.
Planetesimals were massive enough to have a gravitational field sufficient to attract additional
nearby objects. 5. The random motions of material in the collapsing gas cloud were reduced to the
final motion of the material rotating in a disk. 6. The inner parts of the continuing, flattening cloud
free fell into the growing object at the center. 7. Continued motions brushed smaller particle grains
against larger grains. As this electrostatic "sticking" occurred, the particle grains became larger. 8.
Cloud of molecular gas started to collapse due to gravity or other astrophysical process. Use the
number of the process to order them from earliest to latest (left to right).Temperature and
Formation of Our Solar System Temperature was the key factor leading to the state distribution of
various objects made of different elements and compounds. The graph below shows the
temperature (expressed in kelvins) at different distances from the Sun (expressed in AU ) in the
solar system during the time when the planets were formed. To produce a linear plot, in the usual
sense, the vertical axis is inverted so that temperature goes from high to low starting near the Sun.
Use Figure 1 to fill in Table 1 with the formation temperatures for each planet, including the dwarf
planet, Ceres.Aktranomy 1511 Laboratory Manua! Bond albedo refers to the total radiation
reflected from an object compared to the total incident radiation from the Sun. The geometric
albedo refers to the amount of radiation equally reflected in all directions at all wavelengths off an
object. It is clear that a wide range of planetary formation temperatures existed in the early solar
system. The temperatures at which different compounds form or for which elements have physical
state changes will vary. Since the majority of material in the molecular cl.
1) describe how temperature influenced what materials condensed from t.docxjbarbara1
1) describe how temperature influenced what materials condensed from the nebular cloud.
2) compare and contrast the composition of the inner and outer planets
3) explain the frost line and the influence it has on the formation of planets (in any solar system).
4) explain why our solar system has rocky inner planets and gaseous outer planets and identify the most metal-rich planet in the solar system
5) explain the occurrence of Hot Jupiters
Solution
Solution:
1) During the early stage of evolution , soon after the completion of the cloud collapse , nebula is hot . The mass accretion rate from the nebula onto the star is high . The equilibrium condensation temperature of the Silicates and metal comprises 90 % (by mass) of the condensable solids.The temperature decreases away from the mid plane and away from the Sun. The accretion of gas onto the sun leads to the dissipation of energy . The nebula is heated internally due to this .
Condensation metals include Iron , Nickel and Aluminum . Most metals condense into solids at temperatures of 1000 - 1600 K . Metals made up <0.2% of the Nebular mass.
2) The Inner planets are Mercury , Venus ,Earth and Mars. They are all solid and rocky and similar to Earth . Inner Planets are also called Terrestrial Planets . Inner planets are warmer as these are closer to Sun .
Outer planets are called Jovian Planets and are mainly Gaseous in nature . Outer planets are colder as they are farther away from the Sun. All Outer planets have rings .
3) Frost line is also called the Snow line or Ice line . It is the radial position of condensation or evaporation front which varies over time . With reference to the formation of the planets, it is the distance in the Solar Nebula from the central protostar where it is very cold to where the volatile compounds like water , Ammonia , CO2 ,CO condense into solid ice grains.
4) The temperature of the early solar system explains the Terrestrial nature of the inner planets . As the gases coalesced to form the proto Sun the temperature in the inner SOlar system rose . The temperatures rose to about 2000 K , so only substance which have very high melting points remained solid . That is why the inner solar system planets are all rocky .
5) Planetary migration is responsible for the formation of hot Jupiters. These are formed in the outer regions and then migrate to the inner regions of the Solar system . It forms beyond the frost line , from rock , ice and gases due to core accretion method of planetary formation .
.
Theory of Planetary System Formation The mass of the presol.pdfadislifestyle
Theory of Planetary System Formation The mass of the pre-solar molecular cloud played the
largest role in terms of how the solar system formed. It might have begun with a 100 solar mass
cloud approximately 1 to 2 light years in diameter. It's possible that mutual gravitational attraction
between cloud particles was too weak to start the process. When gravity is too weak, the only
other force strong enough to bring a significant number of particles together is the electromagnetic
force. Barring that, perhaps a nearby shockwave from a supernova explosion caused the initial
motion of material: but once started, gravity took hold, causing the inevitable collapse. The
process it underwent followed a pattern that scientists believe is mirrored everywhere a star exists.
In this activity, you will put the solar system formation process parts in order from the beginning. 1.
Planetesimals accreted material until they became large enough to form planets. 2. Gravitational
potential energy of the collapsing gas cloud was converted into thermal energy. 3. Collapsing gas
cloud rotated faster as the collapse continued due to conservation of angular momentum. 4.
Planetesimals were massive enough to have a gravitational field sufficient to attract additional
nearby objects. 5. The random motions of material in the collapsing gas cloud were reduced to the
final motion of the material rotating in a disk. 6. The inner parts of the continuing, flattening cloud
free fell into the growing object at the center. 7. Continued motions brushed smaller particle grains
against larger grains. As this electrostatic "sticking" occurred, the particle grains became larger. 8.
Cloud of molecular gas started to collapse due to gravity or other astrophysical process. Use the
number of the process to order them from earliest to latest (left to right).Temperature and
Formation of Our Solar System Temperature was the key factor leading to the state distribution of
various objects made of different elements and compounds. The graph below shows the
temperature (expressed in kelvins) at different distances from the Sun (expressed in AU ) in the
solar system during the time when the planets were formed. To produce a linear plot, in the usual
sense, the vertical axis is inverted so that temperature goes from high to low starting near the Sun.
Use Figure 1 to fill in Table 1 with the formation temperatures for each planet, including the dwarf
planet, Ceres.Aktranomy 1511 Laboratory Manua! Bond albedo refers to the total radiation
reflected from an object compared to the total incident radiation from the Sun. The geometric
albedo refers to the amount of radiation equally reflected in all directions at all wavelengths off an
object. It is clear that a wide range of planetary formation temperatures existed in the early solar
system. The temperatures at which different compounds form or for which elements have physical
state changes will vary. Since the majority of material in the molecular cl.
Astronomy- State of the art is a course covering the hottest topics in astronomy. In this section, the exotic end states of stars are discussed, including pulsars, neutron stars, and black holes.
(figure 15.18 The planets drawn to scale.)diameter of Neptu.docxjoyjonna282
(
figure 15.18
The planets drawn to scale.
)diameter of Neptune (the smallest Jovian planet) is three times larger than the diameter of Earth or Venus. Further, Neptune's mass is 17 times greater than that of Earth or Venus (figure 15.18).
Other properties that differ include densities, chemical compositions, orbital periods, and numbers of satellites. Variations in the chemical composition of planets are largely responsible for their density differences. Specifically, the average density of the terrestrial planets is about five times the density of water, whereas the average density of the Jovian planets is only 1.5 times that of water. Saturn has a density only 0.7 times that of water, which means that it would float if placed in a large enough tank of water. The outer planets are also characterized by long orbital periods and numerous satellites.
Internal Structures
Shortly after Earth formed, the segregation of material resulted in the formation of three major layers defined by their chemical composition—the crust, mantle, and core. This type of chemical separation occurred in the other planets as well. However, because the terrestrial planets are compositionally different than the Jovian planets, the nature of these layers differs between these two groups (figure is. i 9).
The terrestrial planets are dense, having relatively large cores of iron and iron compounds. From their centers outward, the amount of metallic iron decreases while the amount of rocky silicate minerals increase. The outer cores of Earth and Mercury are liquid, whereas the cores of Venus and Mars are thought to be partially molten. This difference is attributable to Venus and Mars having lower internal temperatures than those of Earth and Mercury. Silicate minerals and other lighter compounds make up the mantles of the terrestrial planets. Finally, the silicate crusts of terrestrial planets are relatively thin compared to their mantles.
The two largest Jovian planets, Jupiter and Saturn, have small metallic inner cores consisting of iron compounds at extremely high temperatures and pressures. The outer cores of these two giants are thought to be liquid metallic hydrogen, whereas the mantles are comprised of liquid hydrogen and helium. The outermost layers are gases and ices of hydrogen, helium, water, ammonia, and methane—which account for the low densities of these planets. Uranus and Neptune also have small metallic cores but their mantles are likely hot dense water and ammonia. Above their mantles, the amount of hydrogen and helium increases, but exists in much lower concentrations than those of Jupiter and Saturn.
The Atmospheres of the Planets
The Jovian planets have very thick atmospheres composed mainly of hydrogen and helium, with lesser amounts of water, methane, ammonia, and other hydrocarbons. The Jovian atmospheres are so thick that they do not show a clear boundary between "atmosphere" and "planet." By contrast, the terrestrial planets, including Earth, h ...
3. Formation OF THE SOLAR SYSTEM
Gas: 72 % Hydrogen
The stars - the
27 % Helium and
sun is a star- 1% other elements.
form inside H is in the form of
large system of molecules instead of atoms.
GAS and Molecular clouds (MC).
DUST
Dust: tiny solid particles of
called silicates and metals, formed
“molecular in the atmospheres of dying
clouds” stars.
1% of the mass of the MCs is
dust.
4. The Orion Nebula in
dust grains:
the visible
- seeds where
atoms
agglomerate, to
form planets
- absorb heat from
stars preventing
MCs from boiling
off
5. - On average low
Molecular clouds:
dust and gas temp, 50 K
- Near stars it is
hot and glows
- MCs contain
CO that emits
radio radiation
allowing us to
map them
6. Visible IR
The sun formed when a molecular cloud core collapsed under its
gravitational pull.
8. Molecular Solar Nebula
Cloud
The sun and
the planets
formed after
a molecular proto-planets
cloud
collapsed
A parenthesis
to explain “
Conservation
of angular planets
momentum”
9. Conservation of Angular Momentum (L).
L= m(mass) ω(angular velocity) r2 (square of radius)
L= m ω r2 . Or L∝ω r2
Essentially this law tells that that the angular momentum of
an isolated system remains constant.
To spin faster a skater
brings her arms in
reducing her radius of
rotation.
To slow down she
opens up her arms
increasing her radius
of rotation.
(r1)2 ω1 = (r2)2 ω2
10. Example of conservation of angular momentum
(r1)2 ω1 = (r2)2 ω2
http://www.youtube.com/watch
v=AQLtcEAG9v0
11. Formation of a Solar Nebula.
The original MC is cold (10 to 50 K)
and has a small amount of rotation,
The collapsed cloud is smaller and
conservation of angular momentum
tells that it rotates faster.
consequence
Planets revolve in the same
direction and almost in the same
plane.
L∝ω r2
12. As the MC collapses
potential energy is
converted into heat,
so collapsed nebula
gets hotter, and
protosun is hot.
“solar Nebula” =
collapsed molecular cloud where sun forms
13. The Solar Nebula Develops a
Temperature Gradient.
Hot Cold
2 000
Temp. (K)
Gradient =
change of
1 000
temperature
with distance
Distance (AU)
14. Most probable Steps for Planet Formation once
the solar nebula is formed.
A- Condensation
B- Accretion ( planetesimals)
C- Formation of Proto-plantes.
D- Density Differentiation (Only
Terrestrial Planets).
E-Formation of atmospheres
Formation of terrestrial planet took
~ 100 million years.
15. Step 1.
Condensation:
As the solar nebula
cooled, atoms and
microscopic particles
condensed around
the dust particles, just as snow flakes
condenses out of the atmosphere.
( a hot system of gas and dust tends to
dissipate)
16. The temperature gradient determines the elements
that condense in the different regions of the
nebula
Cold
Hot frost
line
Frost line 2 000
Temp. (K)
1 000
Distance (AU)
17. Inside the frost line where the temperature
is high Fe, Ni, Al and silicates condense,
and the terrestrial
planets form.
Cold
Hot
Frost line 2 000
Temp. (K)
1 000
Distance (AU)
18. Beyond the frost line, where the temperature
is lower ices, water, silicates and metals
condense and the Jovian
planets form.
Cold
Hot
Frost line 2 000
Temp. (K)
1 000
Distance (AU)
19. Step Two: Accretion and Formation of
Planetesimals.
When condensation ends accretion begins.
Accretion: gradual
growth of small
particles by clumping
together (electrostatic
forces) and by soft
collisions ).
The larger objects formed by accretion are the
planetesimals.
Planetesimals = solid objects formed in the
proto-planetary disks of the solar nebula.
20. Conservation of angular tells us:
-planetesimals have different
orbits around the protosun
- move in almost the same
direction.
L∝ r ω 2
Some collisions hppened
-By soft collisions planetesimals coalesced into larger
ones.
-Head on collision shatters the planetesimals.
Only a few large planetesimals survived.
21. Step Terrestril Planetesimals Grow
Three. to Form Proto Planets.
Larger
planetesimals
attract smaller
ones, and grow
faster than
smaller ones
given rise to
http://www.nature.com/nature/journal/v473/n734
proto-planets. 8/full/473460a.html?WT.ec_id=NATURE-
20110526
Terrestrial proto-planets are as big as the planets.
22. Important
Where the Jovian protoplanets Where the terrestrial
formed gas and ices were abundant protoplanets formed there
and the protoplanets attracted was no much matter
gasses and ices directly from the available, so when they
nebula forming large atmosphers. formed , they stopped
This process is known as growing and they begun the
gravitational collapse. process known as “density
differentiation “
Source NASA/JPL
23. Density Differentiation of terrestrial planets.
Density differentiation = separation of materials due
to density, mainly in the liquid state.
Before density
differentiation the
terrestrial
protoplanes were
homogeneous in
composition.
24. Initially the young terrestrial protoplanets melted due to
the :
a- heat of formation
b- heat released by
collision of captured
planetesimals and
c- heat released by
radioactive materials
in the interior of these
planets.
25. After differentiation Crust
the Terrestrial planets
essentially had three Mantle
main regions:
the core of mainly
Core
heavy elements, the
mantle a mixture of
heavy-light elements
and a crust of light
elements.
Terrestrial planets formed [~ 100 million years]
26. Graphic representation of the evolution of the Solar Nebula.
Condensation
Accretion and
planetesimals Protoplanets
27. What type of particles condensed out of the
solar nebula near the sun.
a.ices
b.ices and silicates.
c.silicates and metals.
c. silicates and metals
d.Water and gases.
28. The Kuiper belt,
and the Ort cloud
were populated
with ice
planetesimals that
formed out of the
nebula but never
made it into
planets.
The rocky asteroids might be the remains of a
planet that never formed.
29. Most planets formed in
their present orbits.
Neptune and Uranus is
believed to have formed
nearer Jupiter’s orbit.
Gravitational interaction
with Jupiter pushed them
outwardly.
31. Atmospheres of Planets.
a- The atmospheres of
the Jovian were drawn
directly from the
nebula.(Gravitational
collapse.)
Jovian have primary
atmospheres and they
never evolved.
32. b- The gases in the atmospheres of terrestrial
planets were the result of:
out- gassing:
(volcanic
eruption)
collision of comets with the
surface of the planets.
33. As comets collided with the
young terrestrial planets gases
and water were released.
Initially the atmospheres of the
terrestrial planets were hot.
Earth’s and Mars’ cooled down
and the water condensed: rain
happened.
( Maybe it did not rain much on
Mars!!!)
On Earth the rain removed the carbon dioxide
from the atmosphere.
34. Mercury lost its atmosphere because it is too hot and
because it has a low escape velocity.
Venus’ atmosphere never cooled down. So water did
not condensed, (no rain). Its atmosphere remains hot
and unchanged, primeval atmosphere.
Earth is the only planet with running water and with
a Secondary Atmosphere.
There is evidence that long time ago, more than 4
billions year, Mars had running water. Mars What went
wrong there? Where is the water?
35. Planetary impacts:
When the terrestrial
planets were young
large impacts were
common, every 100
years or so.
The Barringer Meteor Small impacts
Crater (Arizona), of meteorites
formed ~ 20 to 40 are still
million years ago, by a occurring .
meteorite of 90 meters
in diameter.
36. The HST imaged
the Shoemaker-
Levy comet as it
fell in Jupiter's
atmosphere.
37. Most traces of larger impacts, on Earth,
have been erased by the movement of the
plates and by erosion.
A giant impact 65 million years ago
might have produced the extinction of
the dinosaurs.
39. Moons
Jovian Planets:
Most larger moons probably formed with their parent
planets, directly from the nebula.
The smaller moons were probably captured asteroids.
The moons are rocky and some are larger than
Mercury and have atmospheres.
Terrestrial Planets:
Mercury and Venus do not have moons.
Mars’ two small moons are captured asteroids.
40.
41. Origin of EARTH and MOON
Earth–Moon system may have formed after a collision with a planetesimal
(the size of Mars).
42. Solar nebula theory explains:
a- the existence of:
TERRESTRIAL, JOVIAN and DWARFS.
b- common age of solar system
c- Origin of space debris.
d- Craters Produced by debris falling on planets.
43. Solar nebula theory explains:
e- the existence of many moons around the
Jovians and a few or none around the Terrestrials.
f.- large tilt of rotation of Uranus and Pluto and
backward rotation of Venus due.
Lack of crust on Mercury. . ( It seem that
Mercury lost its crust when a large
planetesimal collided ith the planet)
g- disk shape of the solar system and common
direction of revolution of planets around sun .
(The planets orbit the sun in the same direction
that the sun rotates).
44. Clearing the Nebula
The gas and dust left over after the solar system
was formed was cleared by the solar wind and by
the sun’s radiation pressure.
The planetesimals left over were :
gravitationally attracted by the planets
or
ejected by close encounters with planets.
This populated the Kuiper and Oort cloud.
45. Planets Around Other Stars or Exoplanets.
The solar nebula theory tells us that planets
around other stars are to be expected.
A total of 777 exoplanets (in 624 planetary
systems and 101 multiple planetary systems)
have been identified as of July 5, 2012
The vast majority were detected through various
indirect methods rather than actual imaging.
46. Stars are a billion
…than the planet times brighter…
V
VVVisual detection
is difficult.
…hidden
in the glare.
From
http://planetquest.jpl.nas
a.gov/gallery/frequentIma
ges.cfm
47. NASA Kepler Mission is a
telescope whose aim is to to
look for Earth-like planets.
NASA's Kepler space
telescope, was designed
to find Earth-size
planets in the habitable
zone of sun-like stars.
Kepler detects planets indirectly, using the "transit"
method.
48. Analyzing the depth of the dip in brightness of the light
curve when a plant transits its “stars” astronomers can
find the radius of the orbit of a planet.
Image Credit: NASA Ames
http://kepler.nasa.gov/Mission/discoveries/kepler14b/
49. The Transit Method
http://eo.ucar.edu/staff/dward/sao/exoplanets/methods.htm
50. Kepler MissionFebruary 02, 2012
P = 28 days 25 Earth masses
New super-Earth detected within the habitable zone
of a nearby star.
http://planetquest.jpl.nasa.gov
51. Anbother method of detection of planets.
Invisible
planet.
The gravitational attraction of the invisible planet
causes the star to wobble.
52. As the invisible planet orbits the star its speed of
rotation constantly changes. The changes are
detected as a Doppler shift. Most of the exoplanets
have been detected in
this way
.
53. A planet around 51 Pegasi, 48 ly away,
was the first planet discovered using
this technique.
Beyond our own solar system, the planets
found so far tend to be large Jovians with
orbits more like terrestrial planets.
Until we can observe terrestrial planets, we
will not be able to draw conclusions about
the uniqueness of our own system. Kepler
telescope is looking out for Earth like
planets.
54. Summary of the Nebula
Theory.
I- A slowly rotating cloud of gas and
dust, 2 ly across, collapses under its own
gravity.
II- Proto- sun forms at center of the
collapsed cloud or SOLAR NEBULA.
III- rotation flattens cloud, forming disk
around proto-sun
IV - planets gradually formed in rotating
disk
V -As luminosity of sun increases, gas
and dust is eventually blown away
55. Which of the following is (are) are explained by
the solar nebula theory?
a- the orbits of the planets are nearly circular, and
almost in the same plane.
b- the planets orbit the Sun is the same direction that
the sun rotates.
c- the terrestrial planets have higher density and
lower mass.
d- comets do not necessarily orbit in the plane of the
solar system.
e. all of the above
e. all of the above
57. Select the correct sequence of the figures in order of
occurrence. (Planet formation)
a- a b c d e b- d a b a c
c- e d c a b d- c e b a d
a
d
b
e
c
58. The image represents
a- FAU’s football stadium b- the Daytona car race
track
c- the Oort cloud d- the Kuiper belt
59. What are the name of the objects inside the
closed dotted lines?
Mars
Sun
Jupiter