GALAXIES AND STARS8.E.4A.1 Obtain and communicate information to model the position of the Sun in the universe, the shapes and composition of galaxies,

and the measurement unit needed to identify star and galaxy locations

GALAXIES

Galaxies are made up of gas, dust, and billions of starsGalaxies have different shapesEllipticalSpherical or flattened disks

SpiralA nucleus of bright stars and 2 or more spiral arms

IrregularNo definite shape

Shapes of Galaxies can change over time as a result of collisions with other galaxies and evolution of galaxies themselves

THE SUN AND THE MILKY WAY

The Sun is a star in the Milky Way galaxyMilky Way is a spiral galaxyThe Sun is located approximately 2/3 of the way from the center of the Milky Way

GALILEO GALILEI

Born on February 15, 1564 in Pisa, Italy“Father of Modern Science” Modernized physics and astronomy

Discovered all objects fall at the same rateCreated a hydrostatic balance for measuring tiny objectsSupported the Heliocentric TheoryDeveloped a telescope of his own, used it to observe the moon’s surface features, Venus revolved around the Sun, and Jupiter’s moons revolved around Jupiter not the Earth providing evidence against the Geocentric Theory

TYCHO BRAHE

Born December 14, 1546Danish astronomer and alchemistPrecise and comprehensive astronomical and planetary observations which influenced future discoveries (Planetary Laws of Motion)

Did not use a telescope for his astronomical observationsDiscovered the variation of the Moon’s longitude for the lunar theory

JOHANNES KEPLER

Born December, 27, 1571From the Holy Roman Empire (modern day Germany)1596, a math teacherWorked with Tycho Brahe and seceded him upon Brahe’s death

Founded the 3 Laws of Planetary MotionUsing Brahe’s data, Kepler discovered that the orbit of Mars was an ellipse

Defended the Heliocentric Theory

3 LAWS OF PLANETARY MOTION

The Orbits of the Planets are Ellipses, with the Sun at one focus of the ellipse

The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse

The Ratio of the squares of the revolutionary periods for 2 planets is equal to the ratio of the cubes of their semimajor axes

LIGHT

Light travels 9.46 x 1012 Km (5.88 x 1012 miles) in a year

Light from the Sun travels 8 minutes before reaching us

Light from the Andromeda galaxy (closest galaxy to the Milky Way) was emitted 2.5 million years ago (before the first humans)

The further away a light is, the older the light is when we see it.

PARALLAX

Method astronomers use to determine how far away stars are

Stars seem to shift in position when viewed from Earth because of Earth’s revolution around the SunParallax shift

Astronomers use the diameter of Earth’s orbit to determine the parallax angle across the sky

EXPANDING UNIVERSE8.E.4A.2 Construct and analyze scientific arguments to support

claims that the universe began with a period of extreme and rapid expansion using evidence from the composition of stars and gases

and the motion of galaxies in the universe

THE UNIVERSE

The Universe is composed of matter and energyAll of the matter in the universe now was in the universe when it formed

EVIDENCE

Evidence to Support Scientist ClaimsLooking for the oldest starNebula (gas and dust) exist in space and are remnants from the formation of the universe

Stars undergo a life cycle, amount of hydrogen gas in the star changes therefore affecting the brightness and color of the star

https://www.youtube.com/watch?v=8FPVIV-LzYM

Measuring the rate of expansion of the universeAstronomers determined the galaxy is expanding based on the color of light emitted from galaxies and stars

As the Universe expands and galaxies move apart, the wavelength of light emitted from those galaxies is stretched which shifts the light toward the red end of the spectrum (red-shift). More distances or faint a galaxy, the more rapidly it is moving away from Earth

https://www.youtube.com/watch?v=o3G_eaSaLck

https://www.youtube.com/watch?v=y5tKC3nEx2I