We continue to Learn a lot about the Solar System by using Space Exploration CHAPTER 11

Section 11.1 The Sun page 390 -Average sized star -Millions of km away -300,000 more massive then Earth, 99% of all mass in our solar system -Approx. 5 billon Years old with 5 billion more to go!

The huge size of the sun causes pressure to build up at the center of the sun as gravity pulls the mass inward… This causes Thermonuclear Reactions that turns H (hydrogen) He (helium) giving off Heat, Light and UV radiation in the process H He Heat, Light and UV radiation Pressure

Solar Radiation - E (energy) Emitted from the sun in the form of Electromagnetic Radiation … E that is carried or radiated in the form of waves that range in length, ex. Microwaves, radio waves, UV waves The Earth is located in the “Goldilocks Zone”, not too hot, not too cold, just right!

SUNSPOTS – dark patches of slightly cooler (3500°C) surface areas on the sun, they increase and decrease in number on an 11-yr cycle. They may be related to changes in the Earth’s climate. SOLAR FLARES – eruptions of gas on the suns surface – can last a few hours, temperatures increase up to 11,000,000°C Creates Solar Winds

Solar Wind page 393 Hot E bubbles “pop” on the surface of the sun and send high E particles rushing past Earth. Earth is protected from this solar wind by its magnetic field. Some of the particles enter the Earth’s atmosphere at the poles where they collide with the gas in the atmosphere to create Auroras (Northern/Southern lights) page 394.

Some solar winds can disturb Earth’s magnetic field and disable satellites, knock out power lines, and expose astronauts to high levels of radiation

Section 11.2 page 398 Characteristics of the Celestial Bodies of the Solar System

The Planets To be a planet you must… … orbit 1 or more stars … be large enough so its gravity holds it in place … be the only body in its orbital path

Astronomical Units (AU) Used to measure distances in space 1 AU = 150 million km (the distance from the Earth to the Sun) 1 AU 5.27 AU

Activity 11-2A: Terrestrial and Jovian Planets Listen to the information contained in the video on the planets and complete the table on page 402! Mnemonic Device to Remember the order of the Planets??? Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune

CriteriaTerrestrial Planets (Inner) Jovian Planets (Outer) SizeSmall (all Earth size or smaller) Large (4 to 11 times greater than Earth) MotionSlow spinning, small orbits Faster spinning, larger orbits CompositionSolid and rockyGaseous Distance from Sun CloserFurther away TemperatureWarmer, but temperatures vary Colder, but temperatures vary DensityGreaterLesser

PLUTO Now considered Dwarf Planet – a celestial body orbiting the Sun that is generally smaller than a planet but massive enough for its own gravity to give it a round shape. However they are not strong enough to clear their orbit of debris There are many other “dwarf planets” some are bigger and some like Pluto have moons

A Comparison of 3 dwarf planets and Earth, notice some have moons and some don’t

COMETS “dirty snowballs” composed of ice, rock and gas Originate from the Kuiper Belt and Oort Cloud They travel in long elliptical orbits around the sun which are affected by the gravitational pulls of other planets It has a long dust tail as sunlight starts to melt the ice, these can stretch millions of km Most famous Halley’s comet which is visable every 76 years or so

Periodicity of Comets: "Period" is the amount of time it takes an object in orbit to return to its starting location.timeobjectstarting location Comets travel in short and long periods around the sun in elliptical orbits

The elliptical orbit of Halley’s Comet

ASTEROIDS Small bodies believed to be the leftover remains of the formation of the Solar System Mostly found in an asteroid belt between Mars and Jupiter They have irregular shapes Range in size from a grain of sand up to 1000km An asteroid up to 1 km would devastate Earth

METEORS Meteoroid – a rocky chunk, broken off an asteroid or planet, which floats through space Meteor – a meteoroid that burns up as it passes through Earths atmosphere, seen as a shooting star Meteorite – a meteoroid that does not burn up fully in the Earths atmosphere and hits the Earths surface

Deep Impact Sites A place where a relatively small object (meteorite) has collided with a larger object (planet) Produces a fairly circular depression in the surface of the larger object referred to as an impact crater