Explore our solar system

In this course we will be exploring our solar system! All images within the sections are currently placeholder, i am also trying to work out how to add audio to this course for free. Thank you for exploring the universe with me!

The point of this course is to understand what is in our solar system their is no need to be stressed about answering questions as long so you try them.If you are reading the PDF version your scores will not be recorded!

What are you doing still reading this?? Go and explore!

Introduction to space!

What exactly is in space? What is out there?

This is a picture of our solar system it consists of jovian planets and terrestrial planets. In this introduction a general outline will be shown of the solar system to understand more about a particular planet just click on the content piece and read about it.

In the picture below you can see the 8 planets (9 including pluto we will explain what is special about pluto later). These 8 planets are consisted of 4 jovian planets (Jupiter, Saturn, Uranus, Neptune) which are made up of mostly gas and have low density. The other 4 planets (Mercury, Venus, Earth, Mars) are high density and rocky surfaces. The asteroid belt is located inbetween this 2 types of planets and consist of mostly comets and asteroids. Finaly the kuiper belt is located past neptune which is a much larger scale version of the asteroid belt and is home to 3 dwarf planets.

In this course after each content section there will be a few questions for the first couple of sections there will only be 1-2 questions but as the course progresses more question will be presented and more critical thinking will be needed. You may also notice as the course progresses each plan

Identify the planets!

  • The sun
  • Mercury
  • Venus
  • Mars
  • Earth
  • Neptune
  • Pluto
  • Uranus
  • Saturn
  • Jupiter

The Sun

Explore the sun!

 We will start of at the sun the heart of our solar system.

Overview

The sun is a dwarf star it is essentially a hot ball of glowing gases its at the heart of our solar system. Its gravity holds the solar system together keeping everything from the biggest planet to the smallest debris in orbit. A stream of electrical charged gases blow outwards in all directions. The connection between the sun and earth brings life to our planet aswell as seasons, ocean currents, weather, climate, raditation belts and auroae . The sun isnt the only dwarf star there are many stars like this one in and around our solar system.

Size and Distance

The size of the sun is about 432168 miles in radius not the biggest star but around about 1.3 million earths can fit inside the sun. The sun is roughly 93 million miles away from earth.

Orbit and rotation

The sun and every that orbits it is located in the milky way. The sun orbits the centre of the milky way bringing all planets, asteroids, comets and other objects along with it. The solar system moves at about 430000 miles an hour this still takes our solar systems about 230 million years to make one complete orbit about the milk way.  The sun spins around once every 25 days at the equator but at the pole it spins about once every 35 days.

Formation

The sun and everything in the solar system formed from a giant, rotating cloud of gas and dust called the solar nebula about 4.5 billion years ago. When the nebula collasped due to overwhelming gravity, it spun so fast it flatten to a disk. The majority of the material was pulled towards the centre with accounts for 99.8% of the mass in our solar system.

One day the sun will run out of energy like all stars and when that does happen the sun will engulf mercury and venus and maybe even earth. Scientists say that the sun is about halfway through its life cycle and will die in about 6.5 billion years.

Structure

The sun in terms of atoms is made up of 91% hydrogen and 8.9% helium, in terms of mass its made up of 70.6% hydrogen and 27.4% helium.

The suns is held together by intense gravitational attraction, poducing immense pressure and temperature at its core. The sun has six regions:

1. The core 

2. The radiative zone 

3. The convective zone  

4. The photosphere 

5. The chromosphere  

6. The corona 

The the centre of the sun the temperature is about 27 million degrees fahrenheit (15 million defrees celsius). The energy produced in the core of the sun produces all the heat and light the sun emits. The energy from the core is carried outward by radiation. It then bounces around the radiative zone taking 170000 years to get from the core to the top of the convective zone. Once on the outer layer of the sun the temperature drops its roughly 2 million degrees celsius in the convective zone and the surface is about 5500 degrees.

Surface

The Surface of the sun the photosphere is roughly about 300 mile think region which is where most of the suns raditiation escapes. This surface is not a solid like most planets but it is infact a layer of gas and radiation. It takes about 8 minutes after the radiation leaves the sun to reach earth.

Atmosphere

Past the photosphere lies the slighty weak chromosphere and the corona which make up the thin atmosphere. This is where we see features such as sunspots and solar flares. The light ommitted from these layers is too weak to be seen against the photosphere but sometimes can be seen suring toal solar eclipses. The chromosphere looks like a red rim aroung the sun, The corona on the other hand looks like a white crown. The temperature here can reach about 2 million degree which is strange and has been a mystery for more the 50 years.

Name the six layers of the sun.

  • The core, Radiative zone, The convective zone, The photosphere, The chromosphere and the corona.
  • The centre, The radioactive zone, outer layer, The photophere, The chromozone, The cornona.
  • The middle, The radio zone, The convict layer, The photo layer, The chromo layer, The coron layer.

Mercury

Explore mercury!

Overview

Mercury is about 47 million kms away from the sun and sometimes even 70 million. If you were to stand on the surface when its at its closest point the sun would appear more than 3 times as large as it does when view form each. The temperature can reach 430 degrees since this planet has no atmosphere the night temperatures can drop to -180 degrees

Size and distance

Mercury is so cloe to the sun that it is hard to directly observe from earth except during dawn or twilight. Mercury can appear indirectly 13 times each century observers on earth can watch mercuty passs across the sun this is called a transit. These transits re so rate that they fall within several days of may and november. The firs two transits of mercury in the 21st century occurred 7th of may 2003 and 8th of november 2006, the next fall on may 9th 2016 and november 11th 2019

Mercury travels around the sun every 88 days at a speed of nearly 50km a second faster than any other planet. one mercury solar day equals 175 earth days.

Exosphere

Mercury does have a atmosphere instead it has a think exosphere made up of atoms blasted off the surface by the solar win and striking micrometeoroids. Since the pressure of the radiation is so high the atoms quickly escape into space and forma tail of neutral particals. Mercurys magnetic field at the surface is only 1 percent of the earths strength. The magnetic field creates intense magnetic tornadoes that funnel the fast hot solar wind down to the surface.

Surface

The surface is very similar to the earths moon, scarred by many impact craters resulting from collisions with meteoroids and comets. Large craters have been created and named including caloris and rachmoninoff these were created by asteroid impacts on the planets surface early in the solar systems history. There are many areas that are smooth but there is also lobe shaped scarps or cliffs some hundreds of miles long an soaring up a mile high.

Mercury has the second highest density after earth with a large metallic core, this has a radius of 2000 kms about 80 percent of the planets radius. In 2007 researches found that the core is mostly molten while the outer shell is only 400km thick.

Discoverys 

The spacecraft mariner 10 was the first space craft to land on mercury which imaged 45 percent of the surface since then mercury has been visited multiple times and almost the entire planet has no been imaged revealing a surface that is mostly extensive volcanism.

One discovery found on mercury is a new landform known as 'hollows' aswell as measurements indicating mercury has a high elements of sulfur and potassium. Mercury may have water ice at its north and sout poles deep inside craters.

 

 

Instead of an atmosphere what does mercury have?

  • External Shield
  • Exosphere
  • Exo Layer
  • thermosphere

Venus

Explore Venus

Overview

Venus is the second planet from the sun and our closest neighbor, it has a similar structure and size to earth. Venus however spins slowly in the opposite direction most planets do. The thick atmosphere traps heat in a runaway greenhouse effect. Venus is the hottest planet in out solar system, below the clouds reveal volcanoes and mountains. Venus is named after the ancient roman goddess of love and beauty.

 

Size and Distance

Venus is similar in size to earth just slightly smaller 6052 kms with an average distance of 108 million kms from each it takes about 6 minutes from sunlight to travel from the sun to venus.

 

Orbit and Rotation

The rotation and orbit on venus is very unusual it is one of two planets to rotate from east to west the other being uranus. it takes 243 earth days to complete one rotation the longest day of any planet in our solar system. The sun doesnt rise and set each day because it rotates in the opposite direction of the sun it takes 117 earth days to complete a day - night cycle. Venus completes its full orbit around the sun in 225 earth days or slightly less than 2 venus day - night cycles. Its orbit around the sun is almost completely circular most planets are more oval. Venus also has a axial tilt of 3 degrees which makes it spin upright so it does not experience noticeable seasons.

Formation and structure 

Venus was formed when gravity pulled swirling gas and dust in to become the second planet from the sun, venus is made up of a central core, a rocky mantle and a solid crust.

Venus is very similar to earth in terms of structure it has an iron core that is approximately 3200 kms in radius.  A hot rocky mantle slowly shaking is above the core due to the heat. The surfact has a very think crust of rock that bulges and moves as venus shifts this creates some volcanoes on venus.

MMountains,valleys and thousands of volcanoes appear on venus. Venus has a mountian similar to earchs mount everest at 8.8 kms high. The landscape is seen to be dusty and temperatures reach 471 degrees. Venus has a large amount of craters but none are smaller than 2kms. Small Meteoroids burn up the atmosphere so only large meteoroids reach the surface.

Atmosphere 

The atmosphere consists of mainly carbon dioxide with clouds of sulfuric acid. The suns heat is trapped within the thick atmosphere resulting in extremely hot surfaces 470+ degree. 30 miles up from the surface is roughly the same temperature as the surface of earth.

Since venus moves forward on the solar orbit but slowly rotates backwards on the axis the clouds zip around the planet every 4 earth days this causes hurricane force winds traveling about 360 kms an hour. If you were to be standing on venus it would look like a very hazy overcast day on earth the atmosphere is so heavy it would look like you were 1.6 kms deep underwater

Life on venus

No actual humans have visited venus but the spacecraft that have been sent to the surface dont last long. The high temperature overheat electronics in spacecrafts so most likely no humans would ever live there. Some scientists believe that at the top cloud layers of venus life could exist there.

Discoveries 

Venus periodically passes across the face of the sun this is called a transit this happens in pairs seperated by more than a century these have occured in 1631, 1639; 1761, 1769; 1874, 1882; 2004, 2012. The next transit isnt until 2117 this is because earths and venus's orbits around the sun are so different. Venus more often passes between earth and the sun without crossing the face of the sun from our perspective

The brightest object in the night sky on Earth (besides our moon), Venus has been observed for millennia. And as one of just two bodies between Earth and the sun, Venus periodically passes across the face of the sun — a phenomenon called a transit. Observing transits of Venus has helped astronomers study the nearby planet and better understand the solar system and our place in it. Transits of Venus occur in pairs with more than a century separating each pair, occurring in 1631 and 1639; 1761, 1769; 1874, 1882; and 2004, 2012. The next transit isn't until December 2117. Such long gaps occur between transits because Earth's and Venus' orbits around the sun are inclined differently, so Venus much more often passes between Earth and the sun without crossing the face of the sun from our perspective

 

How big is Venus?

  • 100kms
  • 9082kms
  • 6052kms
  • 7151kms

What is the Structure of Venus?

  • Motlen core, iron mantle, solid crust
  • Iron core, rocky mantle, solid crust
  • Rocky core, iron mantle, solid crust
  • Iron core, solid crust

Earth and the moon

Explore Earth

Overview

Earth is the third planet from the sun and the fifth largest only slightly larger than our nearby venus. Earth is the biggest terrestrial planet. Earth is the only planet to out acknowledgement that has living things. The name earth is at least 1000 years old. All the planets except for earth were named after greek and Roman gods and goddesses.  Our planet just means ground.

Size and distance

With a radius of 6371 kilometers earth is the biggest terrestrial planet the average distance of earth is about 150 million kms it takes about 8 minutes for light to reach the earth.

Orbit and rotation

It takes about 24 hours to complete one rotation and about 365.25 days to complete one trip around the sun. The extra quarter of a day presents a leap year every 4 years we add one day this is to keep our yearly calendars consistent with out orbit around the sun.

Earths axis of rotation is tilted 23.4 degrees with respect to the plane of earths orbit around the sun. One part of our year the northern hemisphere is tilted towards the sun and southern hemisphere is tilted away. Solar heating is greater in the north producing summer there. Less direct solar heating produces winter in the south. After 6 months the situation is reversed.

Formation and structure

Earth was formed around 4.5 billion years ago when gravity pulled swirling gas and dust it has a central core, a rocky mantle and a solid crust.

Similar to venus earth has a large amount of volcanoes, mountains and valleys. The outer section of earth includes the crust and the upper mantle. It is divided into plates that are constantly moving. An example is the north american plate moves west over the pacific ocean roughly at a rate of the growth of our fingernails. Sometimes these plates can result in earthquakes which is when the plates grind past another , ride up over another, collide to make mountains or split.

The ocean covers nearly 70% of the planets surface and has a depth of about 4kms and contains 97% of all the earths water. More than half of the earths volcanoes are hidden under these oceans the longest mountain range is larger than the andes, rockies and himalayas combined but its underwater.

Atmosphere

Earth has an atmosphere that consists of 78% nitrogen, 21% oxygen and 1% other gases such as argon, carbon dioxide and neon. This atmosphere affects the long term climate and short term local weather shields us from radiation from the sun. It also protects us from meteoroids most of which burn up.

Life on earth

Earth has a great temperature and a mix of chemicals that have made life possible here earth is unique because most of the planet is covered in water since the temperature allows liquid water to exist for long periods of time. These oceans have helped provide a convenient place for life to begin about 3.8 billion years ago.

Moons

Earth only has a single moon and is the brightest and most familiar object in the night sky. it is one of the reasons why our planet is such a great home. Our moon is likely the result of a collision billions of years ago. A large chunk of rock smashed into earth it displace a portions of earths interior resulting in chunks clumped together which formed our moon.

 

 

 

Explore The moon

Overview

The earths moon is the 5th largest moon in the solar system, it is the only place after earth that humans have set foot, it is the brightest and largest object in our night sky, the moon makes earth more livable by moderating our planets wobble on its axis.

Size and Distance

The radius of the moon is roughly 1737.5 kms the moon is less than a thrid of the width of earth. The moon is 384400 kms away from earth which means about 30 earth size planets could fit inbetween earth and the moon. The moon is very slowly moving away from earth about an inch farther away each year.

Orbit and rotation

The moon rotates at the same rate that it revolves around earth. As the moon orbits earth, different faces of the moon are in sunlight or darkness at different times. From our perspective the moons goes through phases. First phase is the full moon the hemisphere of the moon we can see from earth is fully illuminated by the sun. Then the new moon occurs when the far side of the moon has full sunlight and the side facing us is having its night. Roughly it takes the moon 27 earth days to complete its orbit around earth.

Formation and structure

The main theory of the moons origin is that a mars size body collided with earth about 4.5 billion years ago. This resulted in debris from both earth and the impactor the moon was in a motled state but this changed and became crystallized with less dense rocks floating upwards and became the lunar crust.

The moons core is smaller than most terrestrial bodies. The solid iron rich inner core is about 240 kms in radius. This is then covered by a liquid iron shell 90 kms thick then a molten layer 150kms thick covers the iron core.

The mantle extends from the top of the partially molten layer to the bottom of the moons crust. This is most likely comprised of olivine and pyroxene. 

The crust is about 70 kms thick and the near-side hemisphere and 150kms thick on the far side. This is made up of oxygen, silicon, magnesium, iron, calcium and aluminium. The moon does have volcanoes but none are active since they have not erupted for millions of years.

Surface

With a lack of an atmosphere the moon is vulnerable to asteroids and meteoroids and comets. Over Billions of years these impacts have ground up the surface of the moon into fragments ranging from huge boulders to power. The moon is almost filled with charcoal grey powdery dust and rock debris called lunar regolith. 

The light areas of the moon are konwn as highlands. These are dark areas which are impact basins that were filled with lava between 4.2 and 1,2 billion years ago. The light and dark areas can be represent with rocks of different composition and ages. The craters themselves have been perserved for billions years.

Looking at the right places on the moon you can find pieces of equipment, american flags and even a camera left behind by astronauts. The gravity of the moon is 1/6th of the earths which is why in footage of moonwalks, the astronauts are bouncing around. When in the sun the temperate can rach 127 degress but in darkness it can be about -173 degrees

 

Atmosphere and life on the moon

The moon doesnt have much of a atmosphere it is very weak it is caleld a exosphere and it doesnt provide any protection from the suns radiation or meteoroids. After many explorations the moon has no evidence to suggest it has its own living things but the moon could be a site for future humans to life.

Discoveries

Humans have studied the moon for a long time, during the solar eclipse out moon moves between earth and the moon and blocks sunlight, in a lunar eclipse the earth blocks the sun light from the moon so we see earths shadow over the face of the moon.

 

How long does it take for light to reach earth?

  • 19 minutes
  • 2 minutes
  • 8 minutes
  • 6 minutes

What type of surface is the earth mostly made of?

  • Rock
  • Water
  • Hydrogen

What happens to the moon during a lunar eclipse?

  • The moon blocks the sunlight to earth
  • The Earth blocks the sunlight to the moon

Mars

Explore Mars

Overview

Through observations we can see seasonally changing features and white patches at the poles. Bright and dark patches on mars were thought to be vegetation but this is unconfirmed. Mars could be a place for advanced life forms and water but when mariner 4 flew over mars it just seemed like a dead planet but in later years mars seems like a complex plan with many mysteries yet to be solved.

Structure 

Mars has a rocky body about half the size of earth aswell as the other terrestrial planets many volcanoes, craters, crustal movement and dust storms seem to have altered the surface of mars.

Scientists do belive that mars experience floods about 3 billion years ago though this might be false as we dont know where it came from or how long it lasted or where it went. Mars odyssey(2002) detected hydrogen rich polar deposits indicating large amounts of water close to the surface. Rover opportunity (2004) found structures and minerals indication that liquid water once exists. 

Moons

Mars does have 2 small moons, phobo and deimos they may be captured asteroids. potato shaped they have too little mass for gravity to make them spherical. phobos is heavily cratered with deep grooves on its surface

Orbit and rotation

Mars experiences season due to the tilt of its rotational axis. mars orbit is about 1.5 times farther fromt he sun than earths so the distance from the sun changes. This effects the length of the season which vary in length. The polar ice caps on mars grow and recede with the season. The areas near poles might show that the planets climate has changed more than once. Volcanism were active about 3 billion years ago. Mars is home to the largest volcano in the solar system, olympus mons, aswell as a spectacular equatorial canyon system, valles marineris .

Atmosphere

The cold temperatures and thin atmosphere dont allow liquid water to exist at the surface. learning how water on mars works is important to understand the planet since water is an essential ingredient for life. For now mars doesnt seem like a possible place for life to sustain.

Discoveries

Phoenix mars lander (2008) was the first mission  to touch water ice in mars . Snow could be observed falling from the clouds this led scientists to belive that the phoenix landing site had a wetter and warmer climate in past few million years. At the moment rover curiosity is examining martian rocks and sol at the gale crater looking for minerals that formed in water.

When did a lander first TOUCH water on mars?

  • 2012
  • 2002
  • 2004
  • 2008

Mars has two moons ___ and ___

Mars has two moons and 

Middle of the solar system!

What is your favourite planet? and why?

Jupiter

Explore Jupiter

Overview

Jupiter is the fifth planet in our solar system and the largest. Jupiter has stripes running through it this just represents a cold, windy clouds of ammonia and water. The atmosphere is mostly hydrogen and helium. The giant red spot is a massive storm that is bigger than earth that has been raging for hundreds of years. Jupiter is also surrounded by 53 confirmed moons and 14 provision ones. The Four largest and most researched planets are: Europa, Callisto, Ganymede and Io. Jupiter also has three rings but are very hard to see this planet is named after the king of ancient gods.

Size and distance

Jupiter has a radius of 69,911 kms which makes it 11 times wider than earth. If earth were a nickel jupiter would be the size of a basketball. Jupiter has an average distance of 778 million kms. It takes about 43 minutes for sunlight to travel to jupiter.

Formation and Structure

4.5 billion years ago when gravity pulled swirling gas and dust in to become the gas giant it took most of the mass left over after the sun ending up with twice the combined material of the other bodies int eh solar system. This means jupiter has the same ingredients as a star but it didn't grow massive enough to ignite

Jupiter is mostly made of hydrogen and helium. The deeper in the atmosphere the pressure and temperature increase. This compresses the hydrogen gas into a liquid and gives jupiter the largest ocean in the solar system itis just made of hydrogen instead of water. Halfway to the planets core the pressure becomes so great that the liquid electrically conducts like a metal. The fast rotation speed of jupiter is enough to make a electrical current throughout the region thus creating a powerful magnetic field it could possibly be 50000 degrees and made mostly of iron and silicate minerals.

 

Surface and atmosphere

Since this planet is a gas giant it doesnt have a true surface its mostly swirling gases and liquids.  If a spacecraft were it fly through jupiter it wouldnt be able to land or to fly through it. The extremely high pressures and temperatures the spacecraft would melt and vaporize.

As a gas giant, Jupiter doesn't have a true surface. The planet is mostly swirling gases and liquids. While a spacecraft would have nowhere to land on Jupiter, it wouldn't be able to fly through unscathed either. The extreme pressures and temperatures deep inside the planet crush, melt and vaporize spacecraft trying to fly into the planet.

Jupiters appearance is a colourful could it has about 3 distinct cloud layers in its skies that span about 71 kms. The top cloud is made of mostly ammonia ice while the second layer is likely ammonium hydrosulfide crysals. The last layer is mostly water ice and vapor.

The colours that made together may be gases rising from the planets warmer interior. Jupiters fast rotation spinning once every 10 hours causes strong jet streams. with no solid surface to slow the planet down it can persist many years. This planet is swept by over a dozen prevailing winds, Some reaching 539 kms per hour. The great red spot which is a swirling oval of clouds twice as wide as earch has been ovserved for 300 years but recently there has been a discovery 3 smaller ovals merged to form the little red spot

Life on jupiter

No life as we know it exists on jupiter. The temperatures, pressures and materials are too extreme for organisms to adapt to. While the planet itself can have living things some of its many moons can. Europa is the likeliest place to file life. There is a vast ocean just beneath its icy crust.

Moons

Jupiter has four very large moons and many more smaller moons it has a confirmed 53 moons and 14 provisional moons. These new moons will have their orbits confirmed then added to jupiters confirmed moon count.

Io, Europa, ganymede and callisto were first observed by the astronomer galileo galilei in 1610. There four moons are very fascinating Io is the most volcanically active body in our solar system. Ganymede is the largest moon in the solar system. Callisto has very dew small craters indicate to a small degree of current surface activity. Europa is a liquid-water ocean with ingredients for life  underneath the frozen crust of europa.

Rings

Jupiters rings are composed of small, dark particles and are difficult to see except when backlife by the sun. The ring system may be formed by dust kick up as interplanetary meteoroids smash into the giant planets small moons.

Exploration

Pioneer 10 and 11 aswell as voyager 1 and 2 were to first to fly by jupiter in the 70s. Galileo orbited the gas planet and dropped a probe into its atmosphere, Cassini took detailed photos of jupter aswell as new horizons. Juno arrived in the jovian system in july 2016.

 

What spacecrafts have taken photos/explored jupiter?

  • ​Pioneer 10 and 11, Voyager 1 and 2, Galileo, Cassini, New Horizons, Juno
  • Pioneer 1 and 2, Voyager 10 and 11, Galio, Cassi, Old horizons, Juno
  • Pioneer 10 and 11, Voyager 1 and 2, Galileo, Cassini, New Horizons

How many moons does jupiter have?

Jupiter has confirmed moons and  provisional moons

Name the four largest moons on jupiter.

The four largest moons on jupiter are ,, and 

How does jupiter differ from terrestrial planets?

Saturn

Explore Saturn!

Overview

Saturn is home to thousands of rings its unique in that out of all the four gas giants none are as spectacular or as complicated as saturns. Saturn is similar to most of gas giants in that its made of mostly hydrogen and helium.

Size and Structure

Similar to jupiter saturn is made mostly of hydrogen and helium its volume is 755 times greater than earth and the winds in the upper most atmosphere reach 500 meters per second. In comparasion the strongest hurricane force winds in earth are about 110 meters per second. These fast winds combined with the heat rising within the planets interioud cause yellow and gold bands visible in the atmosphere.

Rings

Saturns rings are mostly made of water ice and braided rings. The dark features in the rings circle the planet at different rates than the surrounding ring materials. Saturns ring system extends hundreds of thousands of kilometers from the planet. Thought the vertical heigh is typically about 10 meters in the main rings. There are billions of ring particals in the entire ring system which range from tiny dusty size icy grains to a few particals as large as a mountains. Their are two tiny moons that orbit in gaps in the rings and keep the gaps open.

Moons

Saturn has 53 confirmed moons and 9 provisional moons. The biggest being titan which is bigger than the planet mercury. Titan is shrouded in a thick, nitrogen-rich atmosphere that might be similar to what earths was like. Saturn also has many icy moons ranging from Enceladus  which has ongoing surface changes, right through to Iapetus with one heimsphere darker than asphalt and the other as bright as snow.  Titan is so large that it affects the orbits of other neat moons at 5150 km across it makes it the second biggest moon. Phoebe doesnt orbit the planet in the same direction as saturn's larger planets. 

Enceladus has a active ice volcanism warm fractures where evaporating ice evidently escapes and forms a huge cloud of water vapor. Each of saturns moons is different and each have a very interesting story.

Structure and Surface

At the centre is  dense core of rock, ice, water and other compounds made solid by intense pressure and heat. Saturn, the rings and many of the moons lie within Saturn's enormous magnetosphere, which is the region of space in which behaviour of electricity is indluenced more by the magnetic field than the solar wind. 

 

What is the unique thing about Saturn? Pick Two

  • The Rings
  • The Orbit rotation
  • The Size
  • The moons
  • The strucure

What is the biggest moon orbiting saturn?

  • Mimas
  • Phoebe
  • Iapetus
  • Hyperion
  • Titan

What are saturns rings made of?

  • Wind and rock
  • Water and ice
  • Atoms
  • Asteroids

Uranus

Explore Uranus!

Overview

Uranus a very cold and windy planet it is surrounded by 13 faint rings and 27 small moons it also rotates at a nearly 90 degree angle which make it appear to spin on its side. When first discovered it was thought to be a comet or a star.

Size and distance

Uranus has a radius of 25,362 kms which makes it 4 times wider than earth. Uranus has a average distance of 2.9 billion kms. It takes about 2 hours and 40 minutes to travel from the sun to Uranus.

Orbit and rotation

One day in Uranus takes about 17 hours to spind or rotate once and about 84 earth years to complete one full orbit around the sun. Uranus is the only planet whose equator is nearly at a right angle. Possibly the result of a collision. This makes uranus have the most extreme season in our solar system. For nearly a quarter of the uranian year the sun shines directly over each pole, plunging the other half of the planet into a 21 year long dark winter. Along with venus it is just one of two planets that rotate in opposite directions.

Formation and Structure

Uranus took shape about 4.5 billion years ago like the rest of out solar system. Uranus along with neptune is one of two ice giants most of the planets mass is made of icy materials which includes water, methane and ammonia. At the core it heats up to 4982 degrees. Uranus gets its blue-green colour from methane gas in the atmosphere. Sunlight passes through the atmosphere and is reflected back out by uranus's cloud tops the red portion of the light gets absorbed which results in a blue-green colour.

Similar to the other gas planets Uranus doesnt have a surface its mostly swirling fluids if a spacecraft where to fly through its atmosphere it would get destroyed due to its extreme pressures and temperatures.

Atmosphere

The atmoshere in Uranus is mostly hydrgen and helium with a small amout of methane which gives off a blue colour. Uranus has dynamic clouds which results in rapidly changing bright features. Uranus has a minimum temperature of -224 degrees which makes it colder than neptune in some places. Wind speeds can reach up to 900 kms per hour and the winds retrograde at the equator. Blowing in the reverse direction of the planets rotation.

 

Moons and Rings

27 known moons have been found on uranus Uranus moons are unique in that they are named after characters from the works of William shakespeare and alexander pope. The inner moons appear to be roughly half water ice and half rock.

Uranus has two sets of rings, the first layer of nine rings consists of narrow, dark, grey rings. The 2nd layer is a mixture of red and blue. 

Discoveries

Voyager 2 was the only spacecraft to travel to uranus after traveling more then 3 billion kilometers in nine years. It gathered much of its information in 6 hours.

 

 

What is unique about Uranus?

  • The moons
  • The size
  • The icy atmosphere
  • The tilting of the planet

Where does Uranus get its colour from?

  • Sunlight
  • Methane
  • The ice
  • Neptune

Neptune

Explore neptune!

Overview

The dark, cold and whipped supersonic winds make up neptune. It is the last of the hydrogen and helium gas giants in our solar system. It is more than 30 times as far from the sun as earth, it takes about 165 earth years to orbit the sun.

It is also the first place located through mathematical predictions rather than regular observation. It was first recorded as a star but when uranus didnt travel like expected to it was discovered that neptune was a planet.

Size, Distance and axis

Nearly 4.5 billion kilmeters from the sun neptune orbits the sun once every 165 days. It is invisible to be seen by a human eye. The highly eccentric orbit of the dwarf planet pluto brings pluto inside neptunes orbit for a 20 year period.

The magnetic field is tipped over by 47 degrees compared with the planets rotation. Neptune's magnetosphere goes through wild variations during each rotation this causes the magnetic field to be about 27 times more powerful than earth

Atmosphere

The Atmosphere extends to great depths, gradually merging into water and other melted ices. Neptunes blue colour is a result of methane similar to uranus but neptune is a more vivid beighter blue so a unknown component is the result of that more intense colour.

Structure

Neptune has winds that can be three times stronger than jupiters and nine times stronger than earths. Voyager 2 tracked a large, oval shaped dark spot know as the Great Dark Spot which was large enough to contain the entire earth. 

Rings

The Ring system contains several faint rings the outer ring which is anmed Adams contains 3 prominent arcs which are name Liberty, Equality and Freaternity. It is hard to understand the existence of arcs because the laws of motion would predict that arcs spead out into a uniform ring. Other ring systems include the Leverrier ring, Galle ring and the Lassell ring.

Moons

Triton is by far the largest of neptunes moons followed by proteus a non spherical moon, Nereid.

Triton is has a surface that resembles the rind of a cantalouple. The ice volcanoes spout what is a mixture of methane, liquid nitrogen and duty but this instantly freezes. The surface reflects so much sunlight that it is one of the coldest objects in the solar system.

Its the only large moon that circles its planet in the opposite direction which suggests that it might have been independent.

 

How was Neptune found?

Neptune was found through  rather than .

kuiper belt

Explore the Kuiper Belt!

The kuiper belt is a disc-shaped region beyonf neptune that extends 30-55 astronomical units (1 astronomical unit(AU) = the distance from earth to the sun. This region is vastly unexplored but its probably populated with hundreds of thousands of icy bodies larger than 100kms across and an estimated trillion or more comets.

The Dwarf planet Pluto is known to be one of the larger objects in the Kuiper belt. It takes about 200 years to complete a full rotation objects in this belt are presumed to be from the formation of the solar system 4.6 billion years ago.

The first discovery of the Kuiper belt was when scientists became looking beyond neptune this took about 5 years but they eventually found a reddish coloured speck more distant than pluto. That was the first discovery and way named after gerard kuiper who proposed that a belt of icy bodies might lay beyond neptune.

Since the Kuiper Belt Objects are so far away it is difficult to measure the actual size of them. With new infrared observations by scientists most of the larger objects have known sizes. The most unusal object found was Haumea which is part of a collisional family orbiting the sun. Haumea collided with another object and with that impact flew out large icy chunks away and sent Haumea spinning end-over-end every four hours. It can spin so fast that it can sometime turn into the shape of a squashed american footbal. Haumea is known to have two small moons Hi'iaka and namaka. 

Astronomers discovered another object beyond neptune it has now been called 'Sedna'. This object approaches the sun briefly during its 10500 year orbit. Sedna doesnt enter the Kuiper belt it however travels along side between 76 AU and 1000 AU from the sun. A year later another object was discovered it has since been named 'Eris' it orbits the sun once every 560 years. Eris has a small moon named Dysnomia.

Since the discover of Eris there was speculation at the time to make it the tenth planet because at the time Pluto was the ninth planet. However a new class of objects was defined called Dwarf planets.

Name the three dwarf planets talked about in this section.

  • Pluto, Ceres, Sedna
  • Eris, Haumea, Pluto
  • Pluto, Eris, Sedna
  • Eris, Haumea, Sedna

Dwarf planets

What exactly is a 'Dwarf Planet'?

A Dwarf planet is very similar to regular planets in that they both have enough mass and gravity to be nearly round unlike odd-shaped asteroids. They also both travel through space in a path around the sun.

So whats the main difference? The biggest difference between these types of planets is that a Dwarfs planets path around the sun is full of other objects like asteroids and comets. While regular planets have a clear path around the sun. Most of the collisions happen billions of years ago.

At this current moment in time only 5 dwarf planets have been classified:

Pluto

Pluto is classified as a dwarf planet but is also a member of a group of objects that orbit in a disc like zone beyond the orbit of neptune. This realm is populated with thousands of miniature icy worlds. This object is about 2/3rds of the diameter of earths moon and most likely has a rocky cored surrounded by a mantle of water ice. Plutos mass is about 1/6th that of earths moons but hass more mass than ceres which is a dwarf planet that resides between mars and jupiter.

Pluto takes approximately 248 years to orbit which can take it as far as 49 AU from the sun (Remember one AU is the distance between earth and the sun). Pluto came very close to the sun about 29 AU which help astronomers explore and study the cold, distant world. The orbit of pluto is so obscure that when its orbit is close to the sun its surface changes from a solid to a gas and temporarily form a thin atmosphere. Pluto has such low gravity that it causes the atmosphere to be much more extended in altitude than our planets. Pluto also becomes much colder when it is leaving the sun it is though to change its atmosphere to a freeze and fall as snow on the surface.

Pluto does have a large moon that is half its size called charon this moon is so large that it is sometimes referred to as a double dwarf planet system. Charon is greyer than pluto indicating that they have different surface compositions and structure. Charons orbit around pluto takes about 6.4 earth days and one pluto rotation takes 6.4 days. The moon neither rises or sets but it does hover over the same spot as plutos surface the same side of charon always face pluto which is called a tidal locking. Pluto and charon are tipped on its side like uranus. Pluto rotations backwards from east to west also like uranus.

It is extremely hard to observe these to objects only in the late 1980 were astronomers able to make maps of each body because pluto and charon passed in front of each other for several years. Scientists recently found two tiny moons orbiting the same place as charon called nix and hydra these moons are three times farther away from pluto than charon. Two more moons were found in 2012 called kerberos and Styx.

Since pluto is so far away only one hemisphere has been photographed but pluto could be around 2374 kms in diameter. Mountains and craters can be found on this dwarf planet.

Ceres

Ceres is the largest object in the asteroid belt which is located between mars and jupiter and it is the only dward planet located in our inner solar system. It is the first member of the asteroid belt to be discovered.  It was originally called an asteroid for many years but it is so much bigger than any other asteroids that it was named a dwarf planet. Even though Ceres is about 25% of the asteroid belts total mass, Pluto is still 14 times bigger.

With a radius of 476 kms. Ceres is 1/13th of the radius of earth. The average distance of Ceres is about 413 million kms . It takes sunlight about 22 minutes to travel from the sun to ceres. It takes Ceres about 4.6 earth years to make one trip around the sun. It makes one rotation every 9 hours making its day length one of the shortest in the solar system. Ceres axis is tilted about 4 degrees that means it spins nearly perfectly upright and doesnt experience season like other titled planets do.

Ceres would have been formed about 4.5 billion years ago it pulled in gas and dust to become a small dwarf planet, however ceres didnt fully finish forming. The gravity of nearby jupiter prevented it from being a fully formed planet.

Ceres is more similar to most terrestrial planets than an asteroid since its much less dense. One of these similarities is its layers but they just arent clearly defined. It is assumed ceres has a solid core and a mantle of water ice. Ceres could possibly be about 25% water if this is true then ceres has more water than earth. Ceres does have a rocky and dusty crust with large salt deposits.

Ceres has alot of small young craters but none larger than 280 kms. The lack of large craters is due to the layers of ice just below its surface this means that the surface could smooth over time. Also the ice volcanoes could have erased some large craters. Inside of these small craters there are regions that are always shadowed its possible that without direct sunlight there could be water ice in them for a long period of time.

Ceres has a small thin atmosphere that contains water vapor that may be produced by ice volcanoes. Ceres is one of the few places where search for sign of life is possible. Ceres has lots of water which is something most planets dont have. It is possible that life could exist here or has existed here if there are a few other conditions met.

Ceres does not have any moons or rings.

Eris

Eris takes 557 earth years to complete its orbit. The orbit of eris is so far extended that we have not yet explored the entire path it takes. This dwarf planet is so far from the sun that the atmosphere collapses and freezes on the surface.  So much sunlight is reflect that temperatures can vary from -217 degrees to about -243 degres. The atmosphere is so thin that it will thaw in hundreds of years as it approaches the sun revealing a rocky surface similar to pluto.

Eris first appeared to be larger than pluto but recent observations indicate that eris is actually smaller than pluto. Eris is far to small and too far away to clearly see but scientists used its tiny moon Dysnomia to measure it which has a orbit lasting about 16 days. This dwarf planet is still to far to be observed properly.

Haumea

This odd shaped dwarf planet is one of the fastest rotating objects in our solar system. It completes a turn on its axis every 4 hours. This quck spin gave this dwarf planet its unique shape. It is roughly the same size as pluto it orbits our sun in the Kuiper belt it takes about 285 earth years to complete a single orbit around the sun. A impact billions of years ago could have given Haumeas spin and created its moons Hi'aka and Namaka. It is believed that Haumea is made of rock and ice.

Makemake

This dwarf planet is located in the Kuiper belt it is slightly smaller than pluto and takes about 310 earth years to complete one orbit around the sun. Astronomers have found signs of frozen nitrogen on makemakes surface. This dwarf planet has a interesting reddish colour. Makemake is unique in the sense that along with eris was the primary reason why the new group of dwarf planets was made.

 

Why is pluto not a planet?

In this section explain why pluto is not a planet and explain if life is possible on this planet.

Complete these true or false statements.

  • Charon is a moon that belongs to Haumea?
  • Dwarf planets have a clear path from asteroids?
  • Makemake takes 310 earth years to complete a rotation?
  • Eris has one moon?

Which of these dwarf planets ARENT in the kuiper belt?

  • Pluto
  • Ceres
  • Eris
  • Makemake
  • Haumea

Asteroid belt, comets and meteors

What is in our asteroid belt and what are comets and meteors?

Asteroids can sometimes be called minor planets they are rocky remnants left over from the early formation of our solar system. Most of this rubble can be found orbiting the sun between mars and jupiter within our main asteroid belt. These asteroid can be any size ranging from about 530 kms to about 10 meters. The total mass of all asteroids is combined less than earths moons.

The large majority of asteroids are irregularly shaped, there are a couple that are spherical, and are often pitted or cratered these asteroids often orbit the sun in obscure paterns they can also rotate. Some asteroids are known to have a small companion moon but they are often categorized as double asteroids.

There are three broad categories of asteroids c-, s- and m-.

The c- Type (Chondrite) asteroids are the most common these asteroids consist of clay and silicate rocks they are dark in appearance. The S- types (Stony) are made up of silicate materials and nickel-iron. The m- types are metallic and nickel/iron. The asteroids composition depends on how far from the sun they are formed. Some experience extremely high temperatures after they are form and are melted. The iron sinks to the centre and forces the lava to the surface. Out of all the asteroids that have experienced this only one has survived, Vesta. That doesnt mean all asteroids have melt! Only partial amount.

Due to jupiters massive gravity and occasional close encounters with mars changes the asteroids orbits knowning them out of the main belt and makes them fly into other directions which includes into the orbits of other planets. Some asteroids or fragments are flown into earth and other planets in the past which play a Huge role in altering the geological history of the planets in the evolution of life on earth.

Due to the continuous monitoring of earth and the crossing asteroids whose paths intersect earths orbit any asteroids that are within 45 million kms pose a major impact. This radar is a valueable tool in detecting and monitoring the potential hazards. 

Several aircrafts have flown by and observed asteroids some of these asteroids are called Gaspra, Ida, Mathidle, Eros, Steins, Lutetia, Itokawa and vesta. The largest asteroid apart from Ceres is Vesta

Main Asteroid belt

Most asteroids orbit within the asteroid belt between mars and jupiter this belt contains about 1.1 and 1.9 million asteroids  larger than 1km in diameter not to mention millions of smaller ones. 4.5 billion years ago while planets were being formed jupiter brought an end to the formation of most planets in this region causing small bodies to collide and fragmenting most of them into asteroids.

Trojans

Trojans share an orbit with a planet but however do not collide with it since they gather around 2 special places in the orbit. Here the gravitation pull from the sun and the planet balance the trojans tendency to fly out of ortbit. Most of these asteroids are within jupiters orbit. Many can be found in mars, neptune and even earth.

Near-Earth asteroids

Near-Earth asteroids are objects that pass close by earths orbital path. 100003 near earth asteroids are known and the number over 1km in diameter is thought to be about 860 with a possible 1409 classified as a potential threat to earth

 

Meteors

These are things knowns as Shooting stars they are interplanetary materials falling through earths atmosphere. These objects are hurling through space become meteors and for a few seconds they streak across the sky and create glowing trails.

Everyday about 44000 kms of meteoritic material falls on earth each day. Some of these meteors per hour can be seen on any given night. Sometimes that number increases dramatically which are called meteor showers. These can occur annually or at intervals as earth passes through a trail of dusty debris left by a comet. Some of the most common meteor shows are Swift-Tuttle, Tempel-Tuttle, Halley, Encke. 

Chunks of rock and metal from asteroids that survive their journey and fall through the atmosphere to the ground are called meteorites. Most of these are about pebble or fist size, but however some of these can be larger than a building in the early earth years some large meteorites caused extensive destruction.

The largest intact craters is the barringer meteorite crater in arizona about 1km across. This was formed by a peice of iron metal about 50 meters in diameter. This meteorite is only 50000 years old and is so well preserved  that it has been used to study impact processes, about 170 impact craters have been identified. The largest asteroid impact was about 300 km wide which is called the chicxulub crate in mexico this is the reason why dinosaurs are extinct it also wiped out about 75% of all marine and land animals on earth at the time. This all occured about 65 million years ago.

Their has been only one confirmed story of a human being injured by a object from space, Ann hodges of alabama was severely bruised by a 3.6 kilo stony meteorite that crash through her roof on november 1954.

Comets

Comets are leftovers from the dawn of our solar system 4.6 billion years ago, and they mostly consist of ice coated with dark organic material. Comets possibly could have been the cause of water and organic compounds being present to earth of other parts of the solar system.

These comets can be found beyond neptune that orbit the sun. The icy objects sometimes push by gravity bringing them closer to the sun and they become the so called short period comets. this takes less than 200 years to orbit the sun. In some cases their appearance is predictable because they have passed us before. Many of these comets are long period comets which come form a region called the Oort Cloud which is about 100000 times the distance between the earth and moon, These Oort Cloud comets can take as long as 30 years to complete one triple around the sun.

Each of these comets have a tiny frozen part called a nucleus often no larger than a few kms across. The nucleus can contain icy chunks with embedded dust. As it approaches the sun it develops a atmosphere which cause the comets ice to change to gases so the atmosphere gets larger. These can extend to hundreds of thousands of kms. The pressure of the sunlight and high speedy solar wind and blow dust and gas away form the sun sometimes causing bright trails.

Alot of comets travel a safe distance form the sun. The comet halley comes no closer than 89 million kms but some called sungrazers crash straight into the sun or get so close they break up and evaporate. 

 

What is a meteorite?

  • A Shooting star
  • Chunks of rock and metal that survive the journey through the atmosphere and make it into earth
  • A dwarfs planets moon
  • Chunks of rock that have an orbit around the sun and sometimes collide with earth

What is a trojan?

  • Asteroids that collide with other planets
  • A Shooting star
  • asteroids share an orbit with a larger planet, but do not collide with it

What are sun grazers

Sungrazers sometimes  straight into the  or get so close they .

How are comet trails formed?

  • They are formed when the pressure of sunlight and high-speed wind blow the dust and gas away from the sun

Stars!

Explore the stars!


Introduction

Stars are astronomical objects and represent the most fundamental building blocks of galaxies. The history, dynamics and evolution of the galaxy is shown from the stars age, distribution and composition. The stars are responsible for the manufacture and distribution of heavy elements such as carbon, nitrogen and oxygen. Astronomy is the study of the birth, life and death of stars.

Star Formation

Stars are formed from clouds of dust and scattered throughout most galaxies. The orion nebula is a examble of a dust cloud. Inside of these clouds turbulences gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction. When these clouds start to collapses the centre begins to hear up this is known as a protostar. Inside of its hot core at the heart of the collapsing cloud this will one day become a star. Most stars in the milky way are paired in groups of multiple stars this may be because when star form the spinning clouds of collapsing gas and dust break up into two or three blobs.

When the cloud collapse, a dense, hot core forms and begins to gather dust and gas. The remaining dust can become planets, asteroids or comets or may remain as dust. Sometimes the cloud does not collapse at a steady pace. A amateur astronomer James McNeil discovered a small nebula that appeared unexpectedly near the nebula messier 78 in the constellation of orion. When observers looked at this nebula they found that the brightness appears to vary this might be because of the interaction between the young stars magnetic field and the surrounding gas causes this increase in brightness.

Main Sequence Stars

A star that is the size of our sun requires about 50 million years to mature and the sun will star in the mature phase for about 10 billion years. The stars are fueled by the neclear fusion of hydrongen to form helium deep in their interiors.  The energy within the star provides enough pressure necessary to keep the star from collapsing under its own weight and the energy by which it shines. The main sequency of stars span a wide range of luminosities and colours. The small stars are known as red dwarfs which may contain as little as 10% of the mass of the sun and emit only 0.01% as much energy glowing feebly as temperatures between 3000-4000k. These red dwarf stars are the most common in our universe and have lifespans of tens of billions of years. Massive stars which are known as hypergiants, may be 100 more times more massive than our sun and have temperatures of about 30,000k, these hypergiants emit hundreds of thousands more energu than the sun but only has a few million years lifetime. These stars are extremely rare and only a handful exist in our milky way.

Stars and Their Fates

Most of the time the larger the star the shorter life it has. When all the hydrogen has been fused inside of a star the nuclear reactions cease. When deprived of the energy production needed to support the star the core begins to collapse into itself and becomes much hotter. Since hydrogen is still outside of the core it continues to shell surrounding the core. This hot core also pushes the couter layers of the star outward causing them to expand and cool this transforms the star into a red giant. If a star is massive then the collapsing core may become hor enough to support the more exotic neclear reactions that consume helium and make a variety of heavier elemenets up to iron. Eventually the stars internal nuclear fires and comes unstable this sometimes means burning furiously other times dying down. This can cause the star to pulse and throw off its outer layers. When that happens the star enshrouds itself in a cocoon of gas and dust. 

In general, the larger a star, the shorter its life, although all but the most massive stars live for billions of years. When a star has fused all the hydrogen in its core, nuclear reactions cease. Deprived of the energy production needed to support it, the core begins to collapse into itself and becomes much hotter. Hydrogen is still available outside the core, so hydrogen fusion continues in a shell surrounding the core. The increasingly hot core also pushes the outer layers of the star outward, causing them to expand and cool, transforming the star into a red giant.If the star is sufficiently massive, the collapsing core may become hot enough to support more exotic nuclear reactions that consume helium and produce a variety of heavier elements up to iron. However, such reactions offer only a temporary reprieve. Gradually, the star's internal nuclear fires become increasingly unstable - sometimes burning furiously, other times dying down. These variations cause the star to pulsate and throw off its outer layers, enshrouding itself in a cocoon of gas and dust. What happens next depends on the size of the core.

White Dwarfs

White Dwarfs are the dimmest stars in the universe. They have commanded the attention fo astronomers since the first one was discovered in the middle of the 19th century. The main interest is that white dwarfs represent an intriguing state of matter and that most of the stars in our galaxies including our sun will become a white dwarf when it reaches its final burnt out collapsed state

When the hydrogen is used up the stars core collapses and since its a non renewable energy source the shell of hydrogen will be compressed and heated. The nuclear fusion of the hydrogen will produce a new surge of power that will cause the outer layers of the star to expand until it has a diamter a hundred times its value this is when is called the red giant phase.

Hundred of millions of years after the red giant phase all the stars available energy resources will be used up. The wolf-rayet type star is the exhausted red giant that will puff off its outer layers leaving behind a hot core. This star has a surface temperature of about 50000 degress celsius and is furiously boiling off its outer layers in a fast wind traveling 6 million kms per hour.

A planetary nebula is when the radiation from the hot star hears the slowly moving red giant atmospher and creates a complex and graceful filamentary shell. There are clouds of multimillion degree gas that have been compressed and heared by the fast stellar wind. This will eventually cause the star to collapse to form a white star.

In this state all the material from the star minus the amount blown off in the red giant phase will then be compressed into about 1 millionth of the size of the original star. To compare it will be like have a olive made of the same material the would have the same mass as a automobile. This phase is called 'white' because the surface temperatures will be about 20000 degrees celsius.

First white dwarfs were presented a paradox to astronomers if the white dwarf couldnt produce energy through nuclear fusion then it couldnt generate enough pressure to keep it from collapsing this reminded the scientists that maybe its their theories that are incorrect not the stars. Quantum theory helped resolve the paradox since it shows that the matter in the degenerate states of extremely high density could produce a new type of pressure. The reason is because quantum theory prohibits more than one electron from occupying the same state.

Super Novas

A massive star in our galaxy blows itself apart every 50 years or so to create a supernova explosion. These Supernovas are extremely violent and the force of the explosion generates a blinding flash of radiation and shock waves similar to sonic booms. These supernovas were first classified basic on their optical properties. Type II supernovas show visible evidence for hydrogen in the debris shooting out of the explosion while type Ia explosions do not. These types have been refined and a classification in terms of types of stars that give rise to super novas.  Type II, Type Ib and Type Ic explosion, is produced by the catastrophic collapse of the core of a massive star. A type Ia supernova is produced by a sudden thermonuclear explosion that disintegrates a white dwarf star.

Type II supernovas are seen with alot of bright, young stars such as the spiral arms of galaxies. they apparently do not occur in elliptical galaxies. These bright young stars are typically about 10 times greater in mass of the sun and this leads to the conclusion that type II supernovas are produced by massive stars. Type i supernovas show many of the characteristics of type II supernovas. These supernovas called Ib and type Ic are somewhat different from type II since they have lose their outer hydrogen envelope prior to the explosion. This might be because the hydrogen was pulled away by a companion star.

Core-Collapse supernovas is when the nuclear power source at the center or the core of the star is exhausted this means the core collapses in less than a second. A neutron star is formed when this happens the star releases a enormous amount of energy in the form of neutrinos and heat which reverses the implosion. The central neutron star is then blown away at speeds of about 50 million kilometers per hour as the shock wave races through the now expanding stellar debris this fuses lighter elements into heavier ones and produces a brilliant visual outburst that can be as intense as the light of several billion suns.

A type Ia supernova or a termonuclear is produced by white dwarf stars that condense remnant of what used to be sun like stars. A white dwarf star a dense ball primarily comprimised of carbon and oxygen atoms is the most stable of the stars as long as the mass remains below the so called limit of 1.4 solar masses. If the matter from a companion star or the merger of another white dwarf is pushed over the limit of 1.4 solar masses the temperature in the core of the white dwarf will rise. This will trigger a explosive nuclear fusion that releases an enormous amount of energy. The star explodes in abotu ten seconds leaving no remnant. The cloud glows brightly for many weeks as radio active nickel produced in the explosion decays into cobalt and iron.

Since type Ia supernovas all occur in a star that has a mass of about 1.4 solar masses they produce the same amount of light. This makes them useful as a distance indicator. This means if one Type Ia is dimmer than another one it must be further away.

Because Type Ia supernovas all occur in a star that has a mass of about 1.4 solar masses, they produce about the same amount of light. This property makes them extremely useful as a distance indicator - if one Type Ia supernova is dimmer than another one, it must be further away by an amount that can be calculated. In recent years Type Ia supernova have been used in this way to determine the rate of expansion of the universe. This research has led to the astounding discovery that the expansion of the universe is accelerating, possibly because the universe is filled with a mysterious substance called dark energy.

Neutron stars

Everything in space is mostly empty space even a rock is mostly empty since its matter is made of atoms. A atom is a cloud of electrons orbiting around a nucleus composed of protons and neutrons. This nucleus contains about 99.9 percent of the mass of an atom, Yet it has a diameter of only 1/100,000 of the electron cloud. This electrons take up very little space but the pattern of their orbit defines the size of the atom. which is about 99.99 percent open space.

When we bump into a sold rock it is really a ball of electrons moving through empty space so fast that we can see or feel the emptiness. If the matter wasnt empty and we crush the electron cloud down to the size of a nucleus the rock would be squeezed down to the size of a grain of sand and would still weigh 4 million tons.

These extreme forces in nature is the central part of a massive star collapses to form a neutron star. these atoms are crushed completely and the electrons are jammed inside the protons to form a star composed of neutrons. This creates a tiny star that is like a gigantic nucleus and has no empty space.

If you approached a neutron star the gravitational field would pull your space craft into pieces before you reached the surface. The magnetic fields around the neutron stars are extremely strong aswell. Even if you did make it within a few thousand miles above the surface of the  neutron star you will face another problem. The neutron star rotates so rapidly and the strong magnetic fields combined with rapid rotation create a generator that can produce electric potential differences of quadrillions of voltes. These volts are about 30 million times greater than those of lightning bolts.

The high energy particles can produce beams of radiation from radio through gamma-ray energies. Like a rotating lighthouse beam the radiation can be observed as a pulsing source of radiation or pulsar. Some pulsars like the one in the crab nebula pulse in every wavelength- radio, optical, x-ray and gamma-ray but some pulsaras only pulse in X-rays and some pulse only in gamma-rays.

Neutron stars with magnetic fields that are about a quadrillion times greater than the magnetic field of earth are called magnetars. These magnetic fields are produced when a extremely rapidly rotating neutron star is formed by the collapse of the core of a massive star. This triggers a supernova explosion that expels the outer layers of the star at high speeds. These high rates of rotation intensifies the already strong magnetic field if strong enough a star quake is cause that can produce powerful x-ray flashs. These represent an intermediate type of supernova explosion. These magnetars are more energetic than orfinary supernovas but less than hyper novas and thought to be responsible for gamma ray bursts.

The strongest steady magnetic field produced on earth in a lab is about a million times greater than the earths magnetic field. This is beyoung the orfinary magnetic material. Only on a neutron star where graveity is more than 100 billion times as great as on earth can matter withstand the magnetic fields of a magnetar an even there the neutron stars crust can break apart.

Black holes

When a star runs out of nuclear fuel it will collapse if the core has a mass that is greater than three suns no known nuclear forces can prevent the core from forming a deep gravitational warp in space called a black hole. The black hole does not have a surface in the sense but it is simply a region or boundary in space around a black hole beyond which we cannot see this is called the event horizon. Anything that passes beyond the event horizon is doomed to be crushed as it descends deeper  into gravitational well of the black hole. No bisible light no x-rays nor any other form of electromagnetic radiation can escape. The radius of the event horizon is very small only 30 kilo meters. Astronomers cant see the black hole directly the only way to find one is find circumstantial evidence. 

Large amount of matter must be compressed into a sufficiently small region of space so that no other explantation is possible as for stellar black holes this means that observing the orbital acceleration of a star as it orbits its unseen companion in a double or binary star system.

Its hard to search for black holes but one way to locate them is to  study the x-ray binary systems these systems consist of a visible star in close orbit around an invisible companion star. Ehich might be a black hole the companion star then pulls the gas away from the visible star and as the gas forms a flattened disk. It swirls towards the companion. The friction then causes the gas to heat them to extreme temperatures and then x-rays are produce that flicker or vary in intensity within a second.

Many of these brigh x-ray binary sources have ben discovered. The rapid orbital velocity of the visible star indicates that the unseen companion is a black hole. Then the x-rays in these objects are produced by particles very close to the event horizon. They then disappear beyond the event horizon. Not all matter in the disk around the black hole is doomed. Sometimes some of the gas escapes as a hot wind that is blown away from the disk. This then causes a  dramatic high energy jet which can move at nearly the speed of light.

Black holes do grow the mass of the black hole increases by an amount equal to the amount of mass it capture. The radius of the event horize also increases by about 3 kilo meters. A black hole in the center of a galaxy where stars are densely pack may grow to the mass of billions of suns and become a supermassive black hole.


Re - Design our solar system!

Based on what you have learnt how would you structure our solar system?