science astronomy
Terms and definitions:
Solar system: celestial bodies (planets, moons, and etc) that that orbit around the central star
Planet: A celestial body that orbits a star and spins on its own axes
Star: A star is a hot ball of electrically charged gas
Moon: A natural satellite that orbits a planet
Satellite: An object in space. Can be man-made or natural
Dwarf planets: celestial bodies that are not large enough to create a clear path in its orbit around the sun
Galaxies: A galaxy is an extremely large area of space that contains hundreds of billions of stars along with planets and dust that are all held together by gravity.
Universe: Everything that exists in the form of matter and energy
Inner planets: also known as terrestrial planets since they are made up of rocks and have similar compositions to earth
Outer planets: also known as gas giants since they are made up of mostly gas and are huge
Asteroids: small rocky objects that orbit the sun
Comets: fixed orbits around the sun and is mostly composed of ice and dust. They also have “long tails” which are essentially the visible form of the ice melting off the comet
Meteoroids: Small rocky objects that float in space
Meteor: A meteoroid that has entered Earth’s atmosphere
Meteorite: when a meteor has landed and impacted earth’s surface.
Equinox: When the Earth’s axis is tilted neither away or toward the sun, this is called an equinox (autumn and spring)
Summer Solstice – Occurs on the day that the Sun’s direct rays hit furthest North on the Globe (June 21) longest day of the year
Winter Solstice – Occurs on the day that the Sun’s direct rays hit furthest South on the (December 21) longest night of the year
Luminosity – The amount of energy that a star produces per second – Sun = 1 (A star with a luminosity of 100 is 100x brighter than the sun)
Star cluster: a group of stars that live close together
Also add layers of the sun
Calculations:
AU=1.49x10^8 km
Light year: 9.461 x 10^12 km
Lesson 1:
Planets are always in motion, due to their axis. When the earth is facing towards the sun, it is day, and when it is facing away, it is night. Earth turns counter clockwise.
It takes 24 hours for the earth to complete one revolution (1 day)
In Addition to planet moving, they also orbit the sun mean, it spins around the sun, taking 365.25 days to complete one full rotation
Every 4 years we have a leap year since we don’t account for 0.25 days in 1 year, so we make up 1 day every 4 years.
Earth’s axis is tilted at an angle of 23.4 degrees
The tilt is revolution is the reasons of the seasons
When the northern hemisphere is tilted towards the sun, it is summer in the northern hemisphere and winter in the southern hemisphere
When the southern hemisphere is tilted towards the sun, it is summer in the southern hemisphere and winter in the northern hemisphere
Planets stay in orbit with the sun because it is so big that its gravitational pull keeps us held in an orbit.
Lesson 2:
AU=1.49x10^8 km
Light year: 9.461 x 10^12 km
Lesson 3:
Asteroids: small rocky objects that orbit the sun
Comets: fixed orbits around the sun and is mostly composed of ice and dust. They also have “long tails” which are essentially the visible form of the ice melting off the comet
Meteoroids: Small rocky objects that float in space
Meteor: A meteoroid that has entered Earth’s atmosphere
Meteorite: when a meteor has landed and impacted earth’s surface.
Equinox: When the Earth’s axis is tilted neither away or toward the sun, this is called an
Satellite: An object in space. Can be man-made or natural
Lesson 4:
Just like earth, the moon has its own axis.
The moon orbits around earth and revolves around its axis. Both of these rotations take 27.3 days, meaning that we can only see one side of the moon on the surface of earth
Distance from earth is 384,000 km (moon to earth)
¼ the size of earth
⅙ of earth's gravitational pull
There is no wind, water or atmosphere, meaning that there is no erosion
The moon is a non luminous object. The light you see from the moon is the sunlight being reflected onto the moon
There 8 stages of the moon
Solar eclipse: when the moon is directly in between the earth and sun, creating a large shadow on earth. Depending on where you are located, the moon will block the sunlight completely or partially. It will seem like it is night time
A lunar eclipse is when the earth is directly between the sun and earth. This will cause the moon to get a red-sih look since all the sunlight is being reflected pinto the moon
The umbra covers a large area were the sun is completely not visible
The penumbra is where some sunlight is partially visible
Planetary transit is when planets go between the earth and sun. Since those planets are very far away, it will look like there is a black dot going across the sun.
Lesson 5:
A star is a hot ball of electrically charged gas
All stars are luminous- they produce their light through nuclear fusion in the core. This process will create an immense amount of heat and light, which is released on the surface.
Luminosity – The amount of energy that a star produces per second – Sun = 1 (A star with a luminosity of 100 is 100x brighter than the sun)
A red star is relatively cool – 3 000°C
– A yellow star is relatively hot – 6 000°C
– A white star is hotter still – 10 000 oC
– A blue star is very hot – 20 000°C to 50 000°C
The sun is 109 larger than the earth's diameter
The sun has its own axis of rotation. It takes around 28-35 days
There are 6 layers to the sun
Interior:– Core– Radiative zone– Convective zone
Atmosphere:– Photosphere– Chromosphere– Corona
The corona is the most upper layer is is millions of miles thick
The chromosphere is the orange red layer on the atmosphere
The photosphere is the last part of the sun we can see.
The convection zone is movement of plasma – hot moves toward surface, cooler moves towards core and reheats (convection)
The radiation zone is the layer were solar energy radiates outwards but gets bounced around
The core is where nuclear fusion happens- where it produces light and heat
Lesson 6:
The big bang theory is essentially how the universe was created. This theory states that all matter is compressed into a dense ball, where it eventually explodes. This caused the expansion of the universe where all matter lies
This happened in time zero which was approximately 10-15 billion years ago
cosmic background radiation, better known as electromagnetic radiation is the heat or glow left over from the big bang
Red-shift is wavelengths get longer and more red as objects move away. When we study other galaxies, we can see that on a visible spectrum for wavelengths, we can see that they get more red. This means that galaxies are moving away from each other, thus proving the theory of the big bang theory. This shows that the universe is still expanding from the explosion that happened 10-15 billion years ago.
The doppler effect is when galaxies are moving away from us due to the expansion of the universe
There are theories on how the universe ends
The first is that the universe will continue to expand forever (there won’t be an end because space is infinite)
The second way the universe could end is the Oscillating Universe Theory. This theory states that the universe will continue to expand until it reaches a point where it hits an invisible wall and collapses back in on itself. This would essentially mean that the universe would restart back into the dense ball of matter and energy at time zero. If this were the case, this would also mean that this is an infinite cycle of the big bang going off, then collapsing in on itself and repeating.
The last theory is when the universe expands to the point where it just stops.
Lesson 7
The universe is made up of lots of galaxies and black holes
Galaxies contain a lot of dust, which ultimately form new stars
Our sun and solar system are part of the galaxy called the Milky Way
The Milky Way galaxy contains 400 billion stars – our sun is one of these stars.
The Milky Way is spinning so fast that planets and stars should be able to fly out, but due to the black hole in the middle of the Milky Way, it keeps the stars and planets in a spiral shape, pulling us in.
The black hole at the centre of the Milky Way has been pulling in stars
A black hole forms when a massive star gets too dense to the point where it collapses in on itself. This creates a singularity.