28.solar system origin

7/29/2019 28.Solar System Origin

1/19

The origin of the Solar System


2/19

Small planets beyond PlutoSedna, ~1,3001750 km dia.


3/19

Our Solar System is about 16

billion km, or 10 billion miles, or15 light hours across.

Light travels ~ 300,000 km/sec or

~1.1 billion km/hour


4/19

Our galaxy, the Milky Way


5/19

A galactic center: More than 1 Million stars are visible here!


6/19

Edge-on view of a spiral galaxy. Our galaxy, the Milky Way, would

look very much like it to an outside visitor


7/19

Our galaxy, the Milky Way


8/19

IRAS telescope

image of

Pictoris, a solarsystem in the

making? Red =

solid material.


9/19

Star nurseries in the constellation Sagittarius


10/19

The Big Picture The Big Bang, the birth of the Universe ~ 13 Gy ago,

produced H and He. These elements formed stars

which cluster in galaxies with billions of stars; our

galaxy, the Milky Way, formed ~ 10 Gy ago.

Other elements are synthesized in the interiors of stars

such as Red Giants and Supernovae.

Upon ejection into interstellar space from dying stars,

some elements condense into dust grains (presolar

grains) and amorphous dust, either in stellar

atmospheres or in interstellar space.

Gas and dust collect into giant, cold molecular clouds.

Dense cores collapse into stars, such as the Sun 4.56 Gy

ago and planets, asteroids and comets form.

Asteroids collide and fragments fall on Earth as

meteorites

We study meteorites and the presolar grains which

some of them contain. These tell us about the complex

nucleosynthetic processes that are going on in stars,

such as Supernovae, AGB stars, etc.


11/19

The origin of the Solar System


12/19

The critical role of Earths Moon in helping life start and be

sustained on Earth

Moon adds stability to

Earths rotation, so

less extreme seasons

Moon provides ocean

tides on Earth

promotes early life in

shallow pools

Moon slows Earths

rate of rotationlonger days


13/19

Growth of continents with time


14/19

Old parts of the Moon are very

heavily cratered. This indicates

that early in the history of the

Solar System the Moon and, by

inference, Earth were very

heavily bombarded by highly

destructive bullets from space

(asteroids; comets)

Oldest rocks on Earth are ~3.85

Gy old. Older rocks were

destroyed by impacts anderosion: There is nothing left of

the earliest period of Earth

history!


15/19

The atomic bomb dropped on Hiroshima was ~ 20 kt (1 kt = 1,000 t of TNT; 1 mt = 1,000 kt).

Meteor Crater Arizona = 3 mt = 150 Hiroshima bombs.


16/19

How long does life exist on Earth


17/19

Earth is unique: Do not mess it up!


18/19

Planets outside our Solar System, orbiting other stars, in multiples of

Jupiter masses (Mj). Conclusion: Most planets have masses equal to,

or a few times, the mass of Jupiter

Pl t t id S l S t biti th t l tt d


19/19

Planets outside our Solar System, orbiting other stars, plotted as a

function of the distance of their star. Conclusion: Most planets orbit

extremely closely to their stars!

28.solar system origin

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