Threeplanetaryformationtheories:

1.

2.

3.

Anotherwayoflookingatplanet formation:

Nature 511, 7507 (2014).

A))

B))

Warm Cold

C))

B))

D))

CarbondioxideMethaneMolecularN

TheAsteroidBelt

TheSolarSystemisfilledwith“leftovers”

TheItokawaasteroid,1,100feet indiameter. AJapanesespacecraftprobe landedonthe asteroid13.June,2019

and

TheKuiperBelt

ThespacecraftNewHorizonsisnowinvestigatingtheKuiperbelt

AsteroidBelt

PlutoisnowregardedasaperturbedKuiperBeltobject,ordwarfplanet. ManyoftheKuiperBeltobjecthavemoons.Thelargerobjectarealmostallspherical,thesmallerarenot

Ultima Thule: thefarthestandmostprimitiveobjecteverexplored

Calledacontactbinary,22mileslong,4billionmilesaway,AND

NewHorizo

nsmission

the Oort Cloud,evenmoredebrisfromtheformationoftheSolarSystem

Examplesofrealplanetformationdisks:

PDS70

TW Hydrae

Sowhichformationtheorydoyouthinkisright?