Pluto and Other Minor Worlds of the Solar System

Comet Hale-Bopp, visible in 1997

Pluto DataPluto Data

Mean Distance from SunMean Distance from Sun

3,663,800,000 miles3,663,800,000 miles 39.4 AU39.4 AU

Diameter at the EquatorDiameter at the Equator

1,457 miles1,457 miles Length of “Year” Length of “Year” (revolution (revolution

around the sun)around the sun)

247.69 earth years247.69 earth years Diameter if Earth = 1Diameter if Earth = 1

0.180.18Length of “Day”Length of “Day”

6.39 earth days6.39 earth days Mass if Earth = 1Mass if Earth = 1

0.002 0.002 SymbolSymbol

Surface Gravity if Earth = 1Surface Gravity if Earth = 10.05 0.05

God of the UnderworldGod of the Underworld

PlutoPluto: In Roman mythology, Pluto (Greek : In Roman mythology, Pluto (Greek Hades) is the god of the underworldHades) is the god of the underworld

The planet received this name because it’s The planet received this name because it’s so far from the sun that it is in perpetual so far from the sun that it is in perpetual darknessdarkness

No RespectNo Respect

Before 2006, Pluto was the smallest planet Before 2006, Pluto was the smallest planet Pluto is one of the largest Kuiper Belt objects, a Pluto is one of the largest Kuiper Belt objects, a

belt of icy worlds that lie beyond the orbit of belt of icy worlds that lie beyond the orbit of NeptuneNeptune

In 2006, the world’s astronomers convened and In 2006, the world’s astronomers convened and decided that Pluto should be demoted to the decided that Pluto should be demoted to the status of “dwarf planet”status of “dwarf planet”

Other dwarf planets now include Ceres, the Other dwarf planets now include Ceres, the largest asteroid, and Eris (Xena), a world largest asteroid, and Eris (Xena), a world recently discovered beyond Plutorecently discovered beyond Pluto

New HorizonsNew Horizons

No Space MissionsNo Space Missions: Pluto has never been : Pluto has never been visited by a spacecraftvisited by a spacecraft

Our best images of Pluto have been obtained Our best images of Pluto have been obtained using the Hubble Space Telescopeusing the Hubble Space Telescope

The HST has been able to discern bright and The HST has been able to discern bright and dark patterns on Pluto’s surfacedark patterns on Pluto’s surface

The New Horizons mission to Pluto was The New Horizons mission to Pluto was launched in January 2006launched in January 2006

The spacecraft will arrive at Pluto in 2015The spacecraft will arrive at Pluto in 2015

Pluto: HSTPluto: HST

Pluto Surface Map (HST)Pluto Surface Map (HST)

Pluto’s Odd OrbitPluto’s Odd Orbit

Eccentric OrbitEccentric Orbit: Pluto’s orbit around the : Pluto’s orbit around the sun is highly eccentric and tilted in sun is highly eccentric and tilted in comparison to the rest of the solar system comparison to the rest of the solar system

At times Pluto is closer to the sun than At times Pluto is closer to the sun than NeptuneNeptune

Pluto’s OrbitPluto’s OrbitPluto closer than Neptune

Similar to TritonSimilar to Triton

CompositionComposition: Pluto is most likely : Pluto is most likely composed of 75% rock and 25% water ice, composed of 75% rock and 25% water ice, similar to Neptune’s moon Triton similar to Neptune’s moon Triton

CharonCharon

CharonCharon: Pluto’s large satellite: Pluto’s large satellite Discovered in 1978 by Jim Christy Discovered in 1978 by Jim Christy Charon is the mythological figure who ferried the Charon is the mythological figure who ferried the

dead across the river Styx in Hades (the dead across the river Styx in Hades (the underworld) underworld)

Charon is unique in that it is the largest moon, Charon is unique in that it is the largest moon, when compared to its primary planet, in the solar when compared to its primary planet, in the solar system (the second largest is earth’s moon) system (the second largest is earth’s moon)

Pluto and Charon could be considered a double Pluto and Charon could be considered a double planet planet

Pluto and Charon (HST)Pluto and Charon (HST)

Nix and HydraNix and Hydra

In 2005, the Hubble Space Telescope In 2005, the Hubble Space Telescope discovered two additional moons of Plutodiscovered two additional moons of Pluto

These moons have been named Nix and These moons have been named Nix and HydraHydra

Pluto System (HST)Pluto System (HST)

http://antwrp.gsfc.nasa.gov/apod/ap060624.html

Lore of PlutoLore of Pluto Clyde TombaughClyde Tombaugh: Pluto was discovered in 1930 by : Pluto was discovered in 1930 by

Clyde Tombaugh of the Lowell Observatory in Flagstaff, Clyde Tombaugh of the Lowell Observatory in Flagstaff, Arizona Arizona

Percival Lowell, famous for his theories of canals on Percival Lowell, famous for his theories of canals on Mars, had predicted the existence of a ninth planet and Mars, had predicted the existence of a ninth planet and started the search carried out by Tombaugh started the search carried out by Tombaugh

Tombaugh photographed portions of the sky and Tombaugh photographed portions of the sky and discovered Pluto as a faint dot in one of his photographs discovered Pluto as a faint dot in one of his photographs

Although it lied close to the position predicted by Lowell, Although it lied close to the position predicted by Lowell, the discovery of Pluto is considered to be a happy the discovery of Pluto is considered to be a happy coincidencecoincidence

Clyde TombaughClyde Tombaugh

Bye Bye PlutoBye Bye Pluto Status of Pluto decided at the 2006 meeting of the Status of Pluto decided at the 2006 meeting of the

International Astronomical Union, (IAU) International Astronomical Union, (IAU) After debate, Pluto was demoted to a new classification After debate, Pluto was demoted to a new classification

called “dwarf planet”called “dwarf planet” Two other dwarf planets are Ceres, the largest asteroid Two other dwarf planets are Ceres, the largest asteroid

and Eris, a body discovered in 2005 that is larger than and Eris, a body discovered in 2005 that is larger than Pluto and lies further outPluto and lies further out

If dwarf planets are added to the traditional planets, then If dwarf planets are added to the traditional planets, then we now have 8 planets and 3 dwarf planets in the solar we now have 8 planets and 3 dwarf planets in the solar systemsystem

20082008: Dwarf planet Makemake added to list: Dwarf planet Makemake added to list 20082008: Objects like Pluto beyond Neptune termed : Objects like Pluto beyond Neptune termed

“plutoids”“plutoids”

IAU 2006 Planet DefinitionIAU 2006 Planet Definition A Planet:A Planet:

Orbits the sun and is not a satelliteOrbits the sun and is not a satellite Is sphere-shapedIs sphere-shaped Has “cleared the neighborhood around its orbit of similar bodies”Has “cleared the neighborhood around its orbit of similar bodies”

A Dwarf PlanetA Dwarf Planet All of the above, but has not cleared its orbitAll of the above, but has not cleared its orbit

““The eight "planets" are: Mercury, Venus, Earth, Mars, The eight "planets" are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune”Jupiter, Saturn, Uranus, and Neptune”

““Pluto is a "dwarf planet" by the above definition and is Pluto is a "dwarf planet" by the above definition and is recognized as the prototype of a new category of trans-recognized as the prototype of a new category of trans-Neptunian objects“Neptunian objects“

New Solar SystemNew Solar System PlanetsPlanets::

MercuryMercury VenusVenus EarthEarth MarsMars

CeresCeres JupiterJupiter SaturnSaturn UranusUranus NeptuneNeptune

Pluto Pluto Eris Eris Makemake Makemake

Eris

Should Pluto Considered a Planet?Should Pluto Considered a Planet?

YesYes It has been called a planet It has been called a planet

since 1930since 1930 It is roundIt is round It has satellitesIt has satellites It has an atmosphereIt has an atmosphere Other planets haven’t “cleared Other planets haven’t “cleared

their orbits”their orbits” Even if it is just one of many, it Even if it is just one of many, it

should be kept as a planet out should be kept as a planet out of traditionof tradition

New Horizons was sent New Horizons was sent because Pluto was the only because Pluto was the only “planet” not visited“planet” not visited

Too difficult to explainToo difficult to explain

NoNo It is too smallIt is too small It is just one of many It is just one of many

thousands of similar worlds thousands of similar worlds beyond Neptune (hasn’t beyond Neptune (hasn’t “cleared its orbit”“cleared its orbit”

Its orbit is odd (tilted, Its orbit is odd (tilted, eccentric)eccentric)

It doesn’t fit terrestrial or jovian It doesn’t fit terrestrial or jovian categoriescategories

Eris is larger, shouldn’t it be a Eris is larger, shouldn’t it be a planet?planet?

We can’t have thousands of We can’t have thousands of planets beyond Neptuneplanets beyond Neptune

Asteroids (between Mars and Asteroids (between Mars and Jupiter) were at first named Jupiter) were at first named planetsplanets

Discovery of the AsteroidsDiscovery of the Asteroids The first astreroid, Ceres, was discovered on The first astreroid, Ceres, was discovered on

New Year’s Day, 1801New Year’s Day, 1801 Father Giuseppi Piazzi discovered a faint, Father Giuseppi Piazzi discovered a faint,

moving object in the skymoving object in the sky He realized that it lay between the orbits of Mars He realized that it lay between the orbits of Mars

and Jupiterand Jupiter Piazzi chose the name Ceres, the Roman Piazzi chose the name Ceres, the Roman

goddess of grain and the protector of Sicily, goddess of grain and the protector of Sicily, Piazzi’s homePiazzi’s home

Ceres is the largest asteroid with a diameter of Ceres is the largest asteroid with a diameter of 623 miles623 miles

CeresCeres

Ceres: HSTCeres: HST

Many AsteroidsMany Asteroids

By 1807, three more asteroids were By 1807, three more asteroids were discovereddiscovered

These are Juno, Pallas, and VestaThese are Juno, Pallas, and VestaSince then, many thousands of asteroids Since then, many thousands of asteroids

have been discoveredhave been discoveredMost asteroids are found between the Most asteroids are found between the

orbits of Mars and Jupiterorbits of Mars and JupiterSome orbits share Jupiter’s orbit (Trojans)Some orbits share Jupiter’s orbit (Trojans)

Asteroid BeltAsteroid Belt

Asteroid ComparisonsAsteroid Comparisons

Names of the AsteroidsNames of the Asteroids

The discoverer of an asteroid is allowed to The discoverer of an asteroid is allowed to choose a namechoose a name

The first names were from classical mythologyThe first names were from classical mythology Eventually, as mythological names became Eventually, as mythological names became

scarce, various other names were usedscarce, various other names were used The Beatles have asteroids, as well as Piazzi The Beatles have asteroids, as well as Piazzi

(Piazzia), and the Space Shuttle Challenger (Piazzia), and the Space Shuttle Challenger astronautsastronauts

First 25 AsteroidsFirst 25 Asteroids

Number & NameNumber & Name

1.1. CeresCeres

2.2. PallasPallas

3.3. JunoJuno

4.4. VestaVesta

5.5. AstraeaAstraea

6.6. HebeHebe

7.7. IrisIris

8.8. FloraFlora

9.9. MetisMetis

10.10. HygeiaHygeia

11.11. ParthenopeParthenope

12.12. VictoriaVictoria

13.13. EgeriaEgeria

Diameter in MilesDiameter in Miles

623623

378378

143143

334334

7373

121121

130130

9494

9494

280280

9393

7979

139139

14.14. IreneIrene

15.15. EunomiaEunomia

16.16. PsychePsyche

17.17. ThetisThetis

18.18. MelpomeneMelpomene

19.19. FortunaFortuna

20.20. MassaliaMassalia

21.21. LutetiaLutetia

22.22. CalliopeCalliope

23.23. ThaliaThalia

24.24. ThemisThemis

25.25. PhocaeaPhocaea

9898

169169

155155

6868

9393

134134

8181

7272

110110

6969

145145

4545

AsteroidsAsteroids: No Accident: No Accident

The existence of a body or bodies The existence of a body or bodies between Mars and Jupiter had been between Mars and Jupiter had been predicted by Bode’s Lawpredicted by Bode’s Law

When Uranus was discovered close to the When Uranus was discovered close to the position predicted by Bode’s Law, position predicted by Bode’s Law, astronomers began searching for a astronomers began searching for a missing object between Mars and Jupitermissing object between Mars and Jupiter

There is no physical explanation for There is no physical explanation for Bode’s Law, it is likely a coincidenceBode’s Law, it is likely a coincidence

Bode’s LawBode’s Law

““Bode's" Law was first described by Daniel Titius Bode's" Law was first described by Daniel Titius (1729-1796) who found that the distances of the (1729-1796) who found that the distances of the planets follow a fixed formulaplanets follow a fixed formula

Bode's Law led astronomers to search for a Bode's Law led astronomers to search for a "missing" planet between Mars and Jupiter. "missing" planet between Mars and Jupiter. Piazzi found Ceres, the first asteroid, in 1801Piazzi found Ceres, the first asteroid, in 1801

Why this works is a mystery.Why this works is a mystery. Most likely an amazing coincidenceMost likely an amazing coincidence

Bode’s LawBode’s Law

SequenceSequence: Start with 0, 3, and then double : Start with 0, 3, and then double each number aftereach number after

Add 4 to the sequence, than divide by 10Add 4 to the sequence, than divide by 10The results are very close to the actual The results are very close to the actual

distances of most of the planets from the distances of most of the planets from the sunsun

Results are in astronomical units. One AU Results are in astronomical units. One AU (astronomical unit) is the average earth-(astronomical unit) is the average earth-sun distance and equals 93,000,000 misun distance and equals 93,000,000 mi

Bode’s Law TableBode’s Law TableAdd 4Add 4 Divide by 10Divide by 10 ActualActual

MercuryMercury 00 44 0.40.4 0.390.39

VenusVenus 33 77 0.70.7 0.720.72

EarthEarth 66 1010 1.01.0 11

MarsMars 1212 1616 1.61.6 1.521.52

CeresCeres 2424 2828 2.82.8 2.82.8

JupiterJupiter 4848 5252 5.25.2 5.25.2

SaturnSaturn 9696 100100 1010 9.549.54

UranusUranus 192192 196196 19.619.6 19.1919.19

NeptuneNeptune 30.0630.06

PlutoPluto 384384 388388 38.838.8 3939

•Neptune doesn’t fit

•Eris average distance = 68AU

•Eris’s Bode distance should be 77.2AU

Origin of the AsteroidsOrigin of the Asteroids

The most widely accepted theory about The most widely accepted theory about asteroids is that they are planetisimals, asteroids is that they are planetisimals, ancient chunks of matter that never ancient chunks of matter that never formed into a planetformed into a planet

Gravitational effects of Jupiter most likely Gravitational effects of Jupiter most likely prevented a planet from forming in this prevented a planet from forming in this areaarea

All known asteroids packed together would All known asteroids packed together would only equal 1/2000 the mass of the earthonly equal 1/2000 the mass of the earth

To Neptune, and Beyond: The To Neptune, and Beyond: The Kuiper BeltKuiper Belt

Kuiper BeltKuiper Belt: A number of : A number of Pluto-like worlds beyond Pluto-like worlds beyond Neptune’s orbitNeptune’s orbit

Icy, rocky worldsIcy, rocky worlds About 1000 known, About 1000 known,

estimated 70,000 objects estimated 70,000 objects in beltin belt

20082008: Term “plutoid” for : Term “plutoid” for dwarf planets beyond dwarf planets beyond NeptuneNeptune

Some Kuiper Belt ObjectsSome Kuiper Belt Objects

Name (date)Name (date)

Pluto (1930)Pluto (1930)

Charon (1978)*Charon (1978)*

Orcus (2004)Orcus (2004)

Ixion (2001)Ixion (2001)

Quaoar (2002)Quaoar (2002)

Eris (2003)Eris (2003)

Sedna (2004)Sedna (2004)

*Pluto’s satellite*Pluto’s satellite

Diameter (mi)Diameter (mi)

14001400

750750

940940

514514

800800

15001500

800-1100800-1100

Distance (AU)Distance (AU)

39.439.4

39.439.4

4040

4040

43.543.5

6868

7878

Pluto & BeyondPluto & Beyond

http://www.gps.caltech.edu/~mbrown/sedna/

SednaSedna

Sedna is the object with the largest known orbit in our solar system

Sedna is the furthest object discovered in our solar system

Its orbit extends outside the Kuiper Belt, approaching the Oort cloud of comets

SednaSedna

CometsComets

Comets are composed mainly of ice and rocky material, but are dark

Comets originate from areas far out in the solar system

Some comets move in toward the sun, and solar energy causes the outer crust of the comet to turn gaseous creating an immense, glowing cloud

Comet StructureComet Structure NucleusNucleus: Icy center: Icy center ComaComa: Glowing cloud : Glowing cloud

surrounding the nucleussurrounding the nucleus Dust tailDust tail: Stream of solid : Stream of solid

particles emitted from the particles emitted from the nucleus (source of nucleus (source of meteor showers on meteor showers on earth), often forms a earth), often forms a curved pathcurved path

Ion tailIon tail: Stream of glowing : Stream of glowing gas emitted from the gas emitted from the nucleus, always points nucleus, always points away from the sunaway from the sun

Structure of a CometStructure of a CometNote: Coma, ion tail, dust tail, nucleus

Comet Lulin (2009)Comet Lulin (2009)

Note coma, dust tail

Hale-Bopp (1997)Hale-Bopp (1997)Dust tail-brown

Ion tail-blue

Comet Holmes (2007)Comet Holmes (2007)

Comet Holmes Comet Holmes developed a huge developed a huge coma, larger than coma, larger than the sunthe sun

GiottoGiotto

Giotto Mission: The Giotto Mission: The first close-up images first close-up images of a comet’s nucleusof a comet’s nucleus

Flew by Comet Halley Flew by Comet Halley in 1986in 1986

Name refers to the Name refers to the artist Giotto who artist Giotto who featured Halley’s featured Halley’s Comet in a 1301 Comet in a 1301 painting of the birth of painting of the birth of ChristChrist

Comet NucleiComet Nuclei

TopTop: Comet Halley : Comet Halley (Giotto)(Giotto)

BottomBottom: Comet Wild 2 : Comet Wild 2 (Stardust Mission)(Stardust Mission)

Giotto’s HalleyGiotto’s Halley

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=26428

Deep ImpactDeep Impact

NASA’s Deep Impact NASA’s Deep Impact mission collided a mission collided a large block of copper large block of copper into the nucleus of into the nucleus of comet Tempel 1comet Tempel 1

Resulting debris was Resulting debris was studied by the flyby studied by the flyby craftcraft

Deep Impact occurred Deep Impact occurred in July 2005in July 2005

Temple 1’s nucleus

Deep Impact: Wild 2 NucleusDeep Impact: Wild 2 Nucleus

Comet HalleyComet Halley Edmond Halley predicted a comet’s return, and realized Edmond Halley predicted a comet’s return, and realized

that they orbit the sunthat they orbit the sun AristotleAristotle: Comets were phenomena of earth’s : Comets were phenomena of earth’s

atmosphereatmosphere Tycho BraheTycho Brahe: Proved that comets are much farther from : Proved that comets are much farther from

the earththe earth HalleyHalley: Comets in 1531, 1607, and 1682 were the same : Comets in 1531, 1607, and 1682 were the same

object with a period of 75-76 yearsobject with a period of 75-76 years Halley predicted that the comet would return in 1758Halley predicted that the comet would return in 1758 German farmer Georg Palitzsch was the first to spot the German farmer Georg Palitzsch was the first to spot the

return of Halley’s cometreturn of Halley’s comet Halley’s Comet was last seen in 1986, and will return in Halley’s Comet was last seen in 1986, and will return in

2061 (take your vitamins)2061 (take your vitamins)

Great CometsGreat Comets

Roughly ever ten Roughly ever ten years, great comets years, great comets appearappear

Great comets are Great comets are spectacularly bright spectacularly bright and largeand large

1965: Ikeya-Seki1965: Ikeya-Seki 1970: Bennett1970: Bennett 1976: West1976: West 1996: Hyakutake 1996: Hyakutake 1997: Hale-Bopp1997: Hale-Bopp 2007: McNaught 2007: McNaught 2007: Holmes2007: Holmes ??

Ikeya-Seki (Oct, 1965)Ikeya-Seki (Oct, 1965)

Hyakutake (1996), 100 Degree TailHyakutake (1996), 100 Degree Tail

Hale-Bopp (1997)Hale-Bopp (1997)

MeteorsMeteors

Also known as “shooting stars”Also known as “shooting stars”Meteors are a streak of light emitted by Meteors are a streak of light emitted by

particles entering the earth’s atmosphereparticles entering the earth’s atmosphereFriction between the particle and gases in Friction between the particle and gases in

the atmosphere cause it to heat and glowthe atmosphere cause it to heat and glow If the particle survives to land to the If the particle survives to land to the

surface, it is termed a meteoritesurface, it is termed a meteorite

Meteor ShowersMeteor Showers

Meteor showers occur Meteor showers occur when earth passes when earth passes through the debris left through the debris left by a cometby a comet

Meteor showers are Meteor showers are predictable events predictable events that occur on the that occur on the same evenings each same evenings each yearyear

Major Meteor ShowersMajor Meteor Showers

Quadrantids—Jan 03Quadrantids—Jan 03Lyrids—Apr 21Lyrids—Apr 21

Eta Aquarids—May 04Eta Aquarids—May 04S. Delta Aquarids—July 29S. Delta Aquarids—July 29

Perseids—Aug 11-12Perseids—Aug 11-12Orionids—Oct 20Orionids—Oct 20Leonids—Nov 17Leonids—Nov 17

Geminids—Dec 13-14Geminids—Dec 13-14

MeteoritesMeteorites

Meteorites represent solid material that Meteorites represent solid material that falls to the earth and survives its trip falls to the earth and survives its trip through the atmospherethrough the atmosphere

Meteorites come in three main categories:Meteorites come in three main categories:StoneStone IronIronStoney-IronStoney-Iron

Stony Stony MeteoritesMeteorites

Iron Iron MeteoritesMeteorites

Widmanstatten Pattern

Flakes of nickel-iron embedded in stone

Types of MeteoritesTypes of Meteorites

Stony-IronStony-Iron

This pallasite meteorite contains crystals of olivine (peridot) embedded in nickel-iron

In 1969, the Allend meteorite created a dazzling blue display in In 1969, the Allend meteorite created a dazzling blue display in the skies near Chihuahua, Mexico, before impactthe skies near Chihuahua, Mexico, before impact

The dark blue color is due to carbon in the meteorite. This meteorite, a carbonaceous chondrite, is believed to contain unaltered material from the early Solar System (chondrules)

SLICED OPEN

Stony: Carbonaceous ChondritesStony: Carbonaceous Chondrites

Rare stony meteoriteRare stony meteorite Contain carbon, and Contain carbon, and

spherical pieces spherical pieces named chondrulesnamed chondrules

Chondrules are Chondrules are thought contain thought contain unaltered material unaltered material from the early Solar from the early Solar SystemSystem

Chondrule

1969, Allende, Mexico

TektitesTektites Another meteorite-Another meteorite-

related phenomena related phenomena are tektitesare tektites

Tektites are a form Tektites are a form of glass created of glass created when meteorites hit when meteorites hit the earththe earth

Tektites are found Tektites are found in specific areas in specific areas probably near the probably near the original impactoriginal impact

Libyan Desert GlassLibyan Desert Glass

Robert Haag and Libyan Desert Glass

http://www.meteoriteman.com/desert01.html

Australite Air PatternsAustralite Air Patterns

This australite tektite This australite tektite shows apparent shows apparent appears to have appears to have solidified in airsolidified in air

Meteor CraterMeteor Crater Meteor Crater in northern Meteor Crater in northern

Arizona is the best preserved Arizona is the best preserved meteor crater on earthmeteor crater on earth

The crater was created about The crater was created about 10,000 years ago by the 10,000 years ago by the impact of an iron meteorite the impact of an iron meteorite the size of a housesize of a house

Many pieces of the original Many pieces of the original meteorite have been meteorite have been recoveredrecovered

The crater is one mile in The crater is one mile in diameter and is a spectacular diameter and is a spectacular tourist attractiontourist attraction

http://www.meteorite.com/meteor_crater/floor_tour/crater_hike_gps.jpg

TunguskaTunguska

• Trees flattened over an Trees flattened over an area 30 km in diameter area 30 km in diameter by the Tunguska Impact by the Tunguska Impact in 1908in 1908

• The Tunguska event The Tunguska event occurred in Siberiaoccurred in Siberia

• The impactor was most The impactor was most likely a comet due to likely a comet due to absence of any meteoritic absence of any meteoritic materialmaterial

ChicxulubChicxulub

• The Chicxulub Crater, The Chicxulub Crater, located in the ocean near located in the ocean near Yucatan, is believed to be Yucatan, is believed to be the impact crater dating the impact crater dating from the extinction of the from the extinction of the dinosaurs, 65 myadinosaurs, 65 mya

• Actual meteorite Actual meteorite fragments from the fragments from the Chicxulub event have Chicxulub event have been discovered in been discovered in Pacific Ocean sedimentsPacific Ocean sediments