Earth/Environmental.Science.

I.can.explain.the.Earth’s.motions.through.space,.including.precession,.nutation,.the.barycenter,.and.its.path.about.the.galaxy..

!  The science that studies the universe that deals with !  Properties of objects in

space !  Laws under which the

universe operates

✤ Kepler: 1571 – 1630 ✓ 3 Laws ✓ 1st law: The orbits of the

planets are ellipses, with the Sun at one focus of the ellipse.

✓ 2nd law: The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse.

✓ 3rd law: The ratio of the squares of the revolutionary periods for two planets is equal to the ratio of the cubes of their semimajor axes.

!  The.Big.Bang.Theory.!  At.one.time,.the.entire.universe.was.confined.to.a.dense,.hot,.superBmass.ball.,.

!  About.13.7.billion.years.ago.a.violent.explosion.occurred,.hurling.this.material.in.all.directions..

!  Marks.the.beginning.of.the.universe..

!  VIDEO.LINK.

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!  Theory of how the bodies of our solar system evolved from an enormous rotating cloud called the solar nebula.

!  Made up of Hydrogen and Helium !  Theory how the planets were formed

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! States that the space between galaxies is expanding, so that they appear to recede from us at velocities that increase with their distance.

! VIDEO LINK

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!  Spiral !  Disk-shaped with concentration of

stars in the center and “arms”extending from the center

!  Contain old and young stars !  Ex) Milky Way Galaxy

!  Elliptical !  Round to oval in shape !  Contain old stars !  Ex) giant diffuse galaxies -largest

!  Irregular !  No definite shape !  Composed of young stars !  Ex) Large and Small Magellanic

Clouds (closest neighbor galaxies)

!  Rotation.!  Revolution.!  Precession.!  Nutation.!  Barycenter.

!  Precession.!  Slight.movement.over.a.period.of.26,000.years.where.Earth’s.axis.points.in.different.directions..

!  Points.to.two.stars.▪  Polaris.▪  Vega.▪  Current.pointing.to.Polaris.

!  Has.no.affect.on.seasons..

!  Nutation.!  Oscillatory.movement.of.the.axis.of.a.rotating.body.(wobble).

!  Observed.during.precession.!  Occurs.about.18.6.years.

!  Barycenter.!  The.point.between.two.objects.where.they.balance.each.other..

!  The.center.of.mass.where.two.or.more.celestial.bodies.orbit.each.other..

!  Barycenter website with animation

!  How.would.you.describe.the.Earth’s.shape.and.appearance?.

! What.affects.its.shape?.