Solar system formation
This presentation is the property of its rightful owner.
Sponsored Links
1 / 65

Solar System Formation PowerPoint PPT Presentation


  • 74 Views
  • Uploaded on
  • Presentation posted in: General

Solar System Formation. Age of the Solar System. The oldest rocks found on Earth are about 4.55 billion years old, not native but meteorites which fall from space. The oldest native Earth rocks are 3.85 billion years old. Radioactive dating.

Download Presentation

Solar System Formation

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Solar system formation

Solar System Formation


Age of the solar system

Age of the Solar System

The oldest rocks found on Earth are about 4.55 billion years old, not native but meteorites which fall from space.

The oldest native Earth rocks are 3.85 billion years old.


Radioactive dating

Radioactive dating

Unstable parent isotopes decay at a constant rate to stable daughter isotopes. By measuring how much of the parent isotope is still present,

and how much of the daughter isotope there is, we can calculate the age of the rock.


Solar system formation

parent

daughter

½ life (millions of years)


Discussion

Discussion

The age of a rock given by radiometric dating is the time since the rock last solidified.

What happens to the lighter daughter elements when the rock is in a molten or gaseous phase?


Formation of the solar system

Formation of the Solar System

The nebular hypothesis

The Sun and planets formed from the gravitational collapse (possibly triggered by nearby supernova) of a single, spherical, slowly rotating cloud of cold interstellar gas and dust.


Discussion1

Discussion

Why does the gas cloud need to be cold?


Consequence

Consequence

Planet formation is a natural outcome of

star formation.

Planetary systems should be common.


Dynamics of the planets

Dynamics of the Planets

  • The planets revolve counterclockwise around the Sun as viewed from above the Sun’s north pole, the same direction that the Sun rotates on its axis.


Discussion2

Discussion

Why can’t all the planets just orbit in any arbitrary direction? Why should they all go around the Sun in the same way?


Solar system formation

2. The major planets have orbital planes that are only slightly inclined with the plane of the equator of the Sun’s rotation, i.e. the orbits are coplanar.


Orbital inclination

Orbital inclination


Orbital inclination1

Orbital Inclination


Discussion3

Discussion

What does this mean for the paths of the planets through the sky?


Discussion4

Discussion

If the solar nebula started as a spherical cloud

why do all the planets lie in a plane above the Sun’s equator. Shouldn’t they be spherically distributed about the Sun?


Solar system formation

Gravity can collapse a rotating cloud only along the axis of rotation.


Discussion5

Discussion

What two changes take place as the solar nebula collapses due to gravity?


Solar system formation

3.The planets move in elliptical orbits that are very nearly circular.


Eccentricities

Eccentricities


Discussion6

Discussion

Why are all the orbits nearly circular? What

happens to planets that formed with

highly eccentric (very elliptical) orbits?


Solar system formation

4. The planets rotate counterclockwise as viewed from above the north pole, the same direction as they revolve, except for Venus and Uranus.


Rotation of the planets

Rotation of the Planets

Period (days)

Axis tilt


Discussion7

Discussion

Why do you think the planets rotate in the same direction and why is this direction in the same sense as the planets orbit the Sun?


Discussion8

Discussion

Unlike all the other planets Venus rotates backward. How would the diurnal and yearly motion of the Sun differ on Venus compared to that of the Earth?


Discussion9

Discussion

Is the solar day longer or shorter than the sidereal day on Venus?


Discussion10

Discussion

Which planet will have the most extreme seasons?


5 the planets orbital distance from the sun follows a regular spacing

5. The Planets’ orbital distance from the Sun follows a regular spacing.

Titius-Bode rule

Write down 0, 3, 6, 12, … each number, after the first, being double the previous value. Add 4 to each and divide by 10.


Titius bode rule and distance

Titius-Bode Rule and Distance

Distance AU

T-B distance AU


A packed solar system

A packed Solar System?

The solar system may be as densely packed as possible. There do not appear to be any orbits stable over the lifetime of the solar system between the current planets.


Solar system formation

6. Most satellites revolve in the same direction as their parent planet’s rotation and lie close to their parent planet’s equatorial plane

An exception is Neptune’s Triton


Discussion11

Discussion

How would you explain this observation with our formation theory of the Solar System?


7 the sun contains 99 8 of the solar systems mass but only 0 5 of the angular momentum

7. The Sun contains 99.8% of the solar systems mass but only 0.5% of the angular momentum


Discussion12

Discussion

If the Sun formed from a single spherical rotating cloud, wouldn’t you expect that all the pieces would have the same angular momentum as the original cloud? How must the solar system have changed since the time of its formation that this is no longer the case?


Discussion13

Discussion

Either the Sun’s rotation rate has slowed over time, or the planet’s have been spun up in their orbits. How could we decide between these two possibilities?


Solar system formation

The Sun rotates once every 33 days, but should rotate once in about 2 hours if angular momentum were distributed evenly.

This two hour rotation rate is common among other young solar mass stars elsewhere in the galaxy as well as higher mass stars.


Slowing the sun s rotation

Slowing the Sun’s rotation

Magnetic breaking – The Sun’s magnetic field might interact with the early solar nebula to slow the Sun’s rotation.

Strong solar winds early in the history of the Sun might have carried the extra angular momentum away.


Solar system formation

8. Long period comets come from all directions and orbital inclinations in contrast to the coplanar orbits of the planets.


Discussion14

Discussion

If the long period comets can have any inclination, what does this tell you about their distribution around the Sun?


2 types of planets

2 types of planets

Terrestrial planets – iron-nickel cores and silicate mantles

Jovian planets – silicate/hydrogen compound (methane, ammonia, water) cores and mostly H and He mantles


Terrestrial jovian planets

Terrestrial & Jovian planets


Density

Density

Mass of the planet divided by the volume of the planet.

Higher density implies a larger percentage of high density materials, such as iron and nickel, lower density implies more silicates.


Mean density of planets

Mean density of planets

Neptune 1.6 g/cm3

Sun 1.4 g/cm3

Jupiter 1.3 g/cm3

Uranus 1.3 g/cm3

Saturn 0.7 g/cm3

Earth 5.5 g/cm3

Mercury 5.4 g/cm3

Venus 5.2 g/cm3

Mars 3.9 g/cm3

Moon 3.4 g/cm3


9 most solid planetary surfaces are heavily cratered

9. Most solid planetary surfaces are heavily cratered


Meteor crater 1 2 km

Meteor Crater (1.2 km)


Arizona from the shuttle

Arizona from the Shuttle


10 all the jovian planets have rings and a large number of moons

10. All the Jovian planets have rings and a large number of moons


Solar system formation

11. All the Jovian planets have a core of icy/rocky material with between 10-15 times the mass of the Earth


12 all planets are enriched with heavier elements in comparison with the solar abundances

12. All planets are enriched with heavier elements in comparison with the solar abundances


The planetesimal hypothesis

The Planetesimal Hypothesis

Fluffy dust grains condensing out of the solar nebula stick together as a result of low-speed collisions, building up to small bodies called planetesimals.


Protoplanets

Protoplanets

As the protoplanets grow by accretion of planetesimals, their gravity increases spurring more accretion.


Simulation

Simulation


Solar nebula composition

Solar nebula composition

We expect that the solar nebula from which the Sun formed, had the same composition as the current solar surface.

98% hydrogen and helium

1.4% hydrogen compounds – CH4, NH3, H2O

0.4% silicate rocks

0.2% metals


Discussion15

Discussion

If the planets and Sun all formed from the

same nebula, why don’t all the planets and the

Sun of the same chemical composition?

The outer planets have about the same

composition as the Sun but the terrestrial

planets do not. Why?


  • Login