The Solar SystemThe Solar System

What's a solar system?What's a solar system?

Patterns in distancesPatterns in distances

1.4 – 1.8 times the distance of previous 1.4 – 1.8 times the distance of previous planet.planet.

Mars to Jupiter doesn't fit.Mars to Jupiter doesn't fit. But asteroid belt where a planet should But asteroid belt where a planet should

bebe Brighter closer to SunBrighter closer to Sun Warmer closer to SunWarmer closer to Sun

•SIZE= volume

•MASS= amount of matter

•DENSITY= mass / volume

•same mass but different densities

•Pattern in density?

How do scientists determine How do scientists determine Size?Size?

http://astronomyonline.org/science/smallanglhttp://astronomyonline.org/science/smallangleformula.aspeformula.asp

Patterns in size, composition, distancePatterns in size, composition, distance

TERRESTRIALTERRESTRIAL

Small sizeSmall size

Low MassLow Mass

Higher densityHigher density

Mostly rockMostly rock

Mercury, Venus, Earth, Mercury, Venus, Earth, MarsMars

JOVIANJOVIAN

Large sizeLarge size

MassiveMassive

Low densityLow density

Mostly gasMostly gas

Jupiter, Saturn, Jupiter, Saturn, Uranus, NeptuneUranus, Neptune

How do scientists determine How do scientists determine composition?composition?

Spectroscopy?Spectroscopy? How about terrestrial planets?How about terrestrial planets?

– - Earth (and Moon), Mars, Venus- Earth (and Moon), Mars, Venus– - Mercury?- Mercury?

How do scientists calculate How do scientists calculate mass?mass?

If it has a satelliteIf it has a satellite Kepler's 3Kepler's 3rdrd law relates semimajor axis, law relates semimajor axis,

orbital period and massorbital period and mass No satelliteNo satellite

Spacecraft to measure gravity. Spacecraft to measure gravity. Calculate mass then compare to that of Calculate mass then compare to that of

Earth.Earth. Then you can calculate density. Compare Then you can calculate density. Compare

to Earth.to Earth. Make a best guess on composition based Make a best guess on composition based

on comparisonson comparisons

How do scientists calculate How do scientists calculate gravity?gravity?

g=-GM/(r*r)g=-GM/(r*r)

g = acceleration of gravityg = acceleration of gravity

(for Earth, g is approximately 9.81 m/s^2)(for Earth, g is approximately 9.81 m/s^2)

G = universal gravitational constant = 6.67x10^-11 Nm^2/kg^2G = universal gravitational constant = 6.67x10^-11 Nm^2/kg^2

M = mass of the object. (Earth M = 5.98x10^24kg)M = mass of the object. (Earth M = 5.98x10^24kg)

r = distance from the center of the gravitating bodyr = distance from the center of the gravitating body

(Earth, r is approximately 6.38x10^6 m)(Earth, r is approximately 6.38x10^6 m)

Patterns in OrbitsPatterns in Orbits

Revolve counter-clockwise

Rotate counterclockwise EXCEPT

Venus, Uranus, Pluto, Triton

orbit in same plane (orbital inclination of less than 7°) EXCEPT Pluto

nearly circular orbits EXCEPT Pluto

Closer to Sun, less atmosphere,

Farther, more atmosphere

No atmosphere = more craters

Why?

How do we know Jovian's aren't pummeled with debris?

Other patternsOther patterns

Other stuff in the Solar SystemOther stuff in the Solar System

Pattern for moons?Pattern for moons?

Pattern with rings?Pattern with rings?

Debris in Our Solar System TodayDebris in Our Solar System Today

Asteroids—rocky bodies several kilometers across which orbit the sun

Meteor? Meteoroid? Meteorite?

Oldest things in our Solar System.

Comets

Billions

Chunks of rock and ice – Kuiper belt

What's “ice”?

Tail

How do scientists know the age How do scientists know the age of our solar system?of our solar system?

Activity next week.Activity next week.

Bring pennies! LOTS OF PENNIES!Bring pennies! LOTS OF PENNIES!

clouds of gas and dust ejected from old stars

gather into regions

new stars can form

How do we know?

Nebula in Orion – birth of stars!

Patterns are clues to the Patterns are clues to the formation of our solar systemformation of our solar system

The Formation of a Solar SystemThe Formation of a Solar System

gas cloud collapses toward the center

Why?

condensation forms at the center, which is called a protostar.

flattened disk of matter surrounds the protostar, which begins to shine

Why?

The Formation of a Solar SystemThe Formation of a Solar SystemThe rising temperature from the sun removes the gas from the inner regions, leaving dust and larger debris.

The planets establish dominance in their regions of the solar system.

After almost all of the remaining gas, dust, and small debris has been collected by the larger objects, the solar system takes on the form we recognize today.

Other Star Systems FormingOther Star Systems Forming

We can look at young star systems developing today. The planets orbiting these stars are formed from the surrounding disks of gas and dust, called protoplanetary disks or proplyds.

PLANET FORMATIONPLANET FORMATION

Within the disk that surrounds the protosun, solid grains collide and clump together into planetesimals.

The terrestrial planets are built up by collisions and the accretion of planetesimals by gravitational attraction.

The jovian planets are formed by gas accretion.

Hawking Video

WHAT DID YOU KNOW?How many stars are there in the solar

system?Only one star, the Sun.Was the solar system created as a direct

result of the formation of the universe?No. All matter and energy were created by

the Big Bang, but the solar system formed billions of years after the Big Bang.

How long has the Earth existed?4.6 billion years.

WHAT DID YOU KNOW? Is Pluto always the farthest planet from the Sun? No. Pluto’s orbit is highly eccentric, bringing the

planet inside Neptune’s orbit for about 20 years every 250 years.

What typical shapes do moons have? Most look roughly like potatoes.