Download Smaller Bodies of the Solar System

Smaller Bodies of the Solar System
Chapter 2 continued
________________

Small, rocky (sometimes metallic) bodies with no
atmospheres.
___________ ___________ or planetoids
 100,000 numbered and 12,000 named
 1-1000 km in size

 most
~
are small
1 million
Asteroids

Divided into classes based upon orbit and spectral
class.
Orbits of Asteroids

_________ _________

a vast ring of hundreds of thousands of rocky objects
circling __________ the orbits of________ and __________
2
to 4 AU from the Sun
Orbits of Asteroids

__________ __________ _________ (NEA’s)
within 1.3 AU of the Sun
 Three categories:

 Armors
 Apollos
 Atens
Three Categories of NEA’s

Amors
 cross
Mars' orbit but do not quite cross Earth's orbit.
than 1,500 Amors are known.
 Eros, which was visited by the Near Earth Asteroid Rendezvous
(NEAR) spacecraft, is an Amor.
 More
Three Categories of NEA’s

Apollos
Earth orbit-crossing asteroids
 orbit periods longer than one year

More than 1,700
 Geographos is an Apollo.

Three Categories of NEA’s

Atens
cross Earth's orbit
 orbital period less than 1 year.
 Roughly 300 Atens are known

Spectral class of Asteroids

C-type (Carbonaceous)




S-type (Silicaceous)




About 17%
Fairly bright objects
Inner Main Belt
M-type (Metallic)




> 75% of all asteroids
Very dark
Outer region of Main Belt
Fairly bright
Metallic iron
Mid Main Belt
Asteroid Ida with moon Dactyl
_______________
____________ ___________ in space
_____________

___________ that encounter Earth’s atmosphere and
________ _________.

“________ _________”
Meteor Shower

occurs when Earth's orbit intersects the orbit of a
meteor stream
Annual Meteor Showers

Occur when earth’s orbit passes through trail of debris of
comet as it orbits Sun
_______________

Meteoroids that _____________ _____________
_____________
Three Categories of Meteorites

___________
 ________
 Same

_________
minerals as rocks on Earth
___________
 Primarily
iron and nickel
 Half as abundant as stony meteorites
 Easier to find

Stony-iron – mixtures of iron and stony
Stony and Iron Meteorites
Meteorites Hitting Earth

Several hundred tons hit the atmosphere every day

Most are small
a
few milligrams
 Largest

70 tons

Grootfontein in southwest Africa
Meteorites hitting Earth

Average speed entering atmosphere



300-2400 mi/hr
decelerate to ~125 mi/hr
Large meteors are slowed very little

more than 200 tons
_____________ _______________
_______________


Winslow, __________
Iron meteor


100 – 165 feet in diameter
Crater is 3900 feet in diameter and 650 feet deep

120 impact craters on Earth
Tunguska Event

natural explosion that occurred at Tunguska River in what is
now Evenkia, Siberia, at 7:17 AM on June 30, 1908
Tunguska Event


Airburst of meteor 4 to 6 miles above Earth’s surface
10 to 15 megaton blast


Impact heard in London
No crater was found
Tunguska Event

Felled an estimated 60 million trees over 800 square miles
Before
After
 2004 XP14
 269,000 miles (slightly farther than the Moon)
 Quarter to half-mile wide
 Class: Apollo
____________
Mixture of ices (both water and frozen gases) and dust
(KNOW)
 highly eccentric orbits which take them far beyond the
orbit of Pluto

Comets

Known since antiquity

Comet Halley


China (240 B.C.)
878 catalogued

184 periodic comets

orbits less than 200 years
Comets

Composition

“__________ ___________”

Small, solid body made of water, CO2, methane, rock, and dust

Deep Impact
Impacted comet 9P/Tempel
July 4, 2005
Parts of a Comet
Comets
___________


solid and stable
mostly ice and gas
 some dust
only a few miles in diameter

Comet Halley
 3 miles in diameter
76 year period
Comets

__________



dense cloud of water, carbon dioxide, and other gases sublimed off
nucleus (KNOW)
Up to 250,000 miles in diameter
begins to form at 5 A.U.
Comets

__________

points _________ from _________

solar wind and radiation push particles and ionize gases

Tens of millions of km long
Path of a Comet
 Evolutionists define comets as primordial
 Existing at or from the beginning, primeval; original, fundamental
What happens to comets when they orbit
the sun?

_________ much of its _________

Typical max age = 10,000 years
Shorter period comets have been observed to dim remarkably
over the years

Gives support to a young world according to creationists

6000 – 10,000 years old
 Can change orbit
 Gravitational interaction with planets
 Can be completely destroyed
 Shoemaker-Levi collided with Jupiter in 1994
Can breakup
What is the Oort Cloud?

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ – a _ _ _ _ _ _ _ _ _ _ c l o u d s u p p o s e d to
exist at the outer reaches of our solar system from which
_________ __ __ _________ ____ _____ c om e .
The Theory of the Oort Cloud
Evolutionists
Oort Cloud

comets come from an unobserved spherical 'Oort cloud' well
beyond the orbit of Pluto
computer simulations have clearly shown that short-period comets cannot
originate from the cloud,

gravitational interactions with infrequently passing stars often
knock comets into the solar system

interactions with planets slow down the incoming comets
often enough to account for the hundreds of comets observed
Not substantiated either by observations or realistic calculations
Not substantiated either by observations or realistic calculations
Problems for the Oort Cloud
None of these assumptions has been substantiated
either by observations or realistic calculations
 The Oort cloud has never been observed and there is
no evidence it even exists!!! (KNOW)

What is the ________ _______?

___________ massive flattened disc of billions of _______
_______ supposedly left over from the formation of the solar
system
proposed as source for long-period comets and a replenisher of the
Oort Cloud.
 beyond Neptune (extending from 30 AU out to around 100 AU).
 occasionally disturbed by gravitational interactions these objects are
sent hurtling into the inner solar system to become short-period
comets
Kuiper Belt Objects

Appear to be a number of small objects beyond the
orbit of Neptune (KBO’s)
Problem with KBO’s
Much larger than comet nuclei
 Several are binary

 They orbit each other
 Statistically difficult for two orbiting masses to be formed randomly

No one can clearly identify a single image as a
comet nucleus
 A major problem is that the imaging system is subject
to random signals, called noise, that mimic these
faint points, so from a single image one cannot have
any confidence that any particular point of light is
real.