6th Grade FCAT 2.0 Study Guide Investigating the Universe

What are the relationships between planets and other astronomical bodies?

Explore Sort the Solar System Cards in the order which they appear in the solar system. Draw and label the planets and astronomical bodies of our solar system in the correct order. Mercury Venus Earth Mars Asteroids Jupiter Saturn Uranus Neptune Comets Varies <940 km 4,878 km 12, 104 km 12,756 km 6,786 km 142.984 km 120,536 km 51,108 km 49,538 km Varies <100 km 19.20

Astronomical Units One AU (astronomical unit) is the distance from ______ to the ____ = 93,000,000 miles or 150,000,000 km. Sun Earth

Astronomical Units As you get further away from the sun, the astronomical units ____________ As you get closer to the sun, the astronomical units ______________ Increase Decrease

The Planets (extra) Inner Outer Inner Planets (closest to the Sun) Mercury, Venus, Earth, Mars Terrestrial – small, dense, with rocky crusts Outer Planets (furthest from Sun) Jupiter, Saturn, Uranus, Neptune Jovian – large, low density, gaseous Inner Outer

Planet G-Force Distance from Sun (in AU) Temp Atmosphere Mercury 0.38 Max. 465 C Min. -184 C Small, almost no air. Venus 0.9 0.72 449 C Thick cloud cover, traps heat. Earth 1 7.2 C Goldilocks’ Conditions Mars 1.5 Max. 36 C Min. -123 C Depleted into space, surface water evaporated. Jupiter 2.36 5.2 -153 C No solid surface, gets thicker, becomes liquid ocean. Saturn 0.92 9.5 -184 C Clouds of methane and helium become liquid. Uranus 0.89 19.2 Same as above. Neptune 1.13 30 -223 C

Planet Size The planets with the largest diameters are ______from the sun. The planets with the smallest diameters are ______ to the sun. farther closer

Universe Space is filled with trillions of stars and groups of stars called ________. galaxies

Universe -(Extra) The universe, the space that we live in, is HUGE. Within the universe are a number of galaxies. Galaxies are islands in space made of very large numbers of stars, dust, and interstellar gas.

Galaxies (Extra) It is estimated that our galaxy, the Milky Way, contains about 100 billion stars. That’s just us! Some galaxies are bigger, some are smaller. Scientists believe there are between 25 and 100 billion galaxies in the universe.

Stars Stars are objects in space, made of gases, which produce their own light and heat. Earth’s nearest star is the sun, which is about 149,600,000 kilometers away.

Light Years The next nearest star, Proxima Centauri, is 4.24 light years away. A __________is a measurement equal to 9.5 trillion kilometers-the distance light travels in 1 year. light year

Stars There are several properties that can be used to describe stars. Different stars produce different amounts of energy. The amount of energy produced by a star determines the star’s color and surface ___________. temperature

Star Temperature The brightest and hottest stars are blue, while the dimmest and coolest stars are red dwarfs.

Age of Stars The age of a star is related to their starting mass. Stars with the smallest starting mass, such as ________, last much longer than stars the start with larger masses. white dwarfs

Stars (Stellar Cycle) Extra Begins as a protostar (collapsing cloud of dust and gas). Star contracts and begins nuclear fusion of hydrogen  burns with a bright light  main sequence star. How long it burns depends on SIZE of the star Bigger stars burn at higher temperatures  blue. Smaller starts burn at lower temperatures  red. Star starts to fuse helium  expand into red giant star. Star blows off outer shell of gases  leaves behind a white dwarf star that eventually cools and no longer produces light.

Luminosity = Absolute Brightness

Brightness of Stars Some stars appear brighter than others, but they may not truly be brighter. The brightness of a star depends partly on its size and partly on its distance from Earth. Larger stars are brighter, but closer stars look brighter.

Apparent magnitude The _________________ is a measure of how bright a star appears to be when you see it from Earth. The __________________ of a star is a measure of how bright the star really is, if all stars were the same distance from Earth. Absolute magnitude

Historical Models of the Solar System (Extra) Our solar system contains ONE star (the Sun), 8 planets, and at least 70 major moons that orbit these planets. Heliocentric everything revolves around the Sun. Geocentric everything revolving around Earth.

Formation of our Solar System (Extra) Sun condensed, contracted, and stabilized. Densest materials formed the inner planets. Less dense, gaseous materials clumped as the outer planets. Other material was pulled in as moons or into the asteroid belt (between Mars and Jupiter).

Sun The sun is the closest star to Earth. Because it is so close, scientists can easily observe it.

Sun The sun and most stars are made almost entirely of hydrogen and __________. A star’s composition changes slowly over time as hydrogen in its core fuses into more complex nuclei. helium

Star’s Inner Layers The interior of a typical star is made of 3 layers.

Star’s Inner Layers radiative convection The core contains helium, the _____________ zone is a shell of cooler hydrogen around the core and the ___________ zone is where hot gas moves up toward the surface. Light energy moves quickly upward in the convection zone. radiative convection

Star’s Atmosphere Layers The atmosphere of most stars is made of three layers. The _____________ is the bright part that you can see where light energy radiates into space. The _______________ is the orange-red layer above the photosphere and The _________ is the wide, outermost layer of a star’s atmosphere. photosphere chromosphere corona

Star’s Atmosphere Layers As a star changes, the features that are visible to scientists change.

Sun Sunspots Prominences Flares __________ are regions of strong magnetic activity and appear as dark splotches. They seem to move across the sun as the sun rotates _____________ are clouds of gas that make loops and jets extending into the sun’s atmosphere and they can last for weeks. __________ are sudden increases in brightness often found near sunspots or prominences. They are violent eruptions that can last hours. Prominences Flares

Planetary Motion (Extra) An ORBIT is the path one celestial body travels around another. All planets orbit the Sun in the same direction, counterclockwise, with their orbits unevenly spaced. In general, orbits are spaced farther apart as their distance from the Sun increases. All the orbits are elliptical (smooshed circle)

Planetary Motion Universal Gravitation gravity The Law of ______________________ explains that all objects are attracted to each other and the strength of the force depends on the mass of each object and the distance between them. The sun is the center of our solar system and is very massive. It exerts gravitational forces on other objects in the Solar System. This gravity causes the objects in space to move around, or orbit, the sun. Without _________ the planets would continue to travel in a straight line and would not orbit the sun. Gravity is also the force that holds stars and galaxies together. gravity

Use evidence from today’s lesson to re-answer the probe Use evidence from today’s lesson to re-answer the probe. You may either change your initial response, or keep it the same, but it MUST be supported by EVIDENCE from the activity and reading.