Science 9-Unit E Astronomy

Ancient views of Cosmos

The first nations people of pacific northwest believed the north sky was a pattern on a great blanket overhead, which was held up by a spinning 'world pole' resting on the chest of a woman named Stone Ribs

Solstice

Represents the longest and shortest periods of daylight

Summer solstice:June 21

Winter solstice:December 21

Equinox

represents periods of equal day

Vernal Equinox:March 21st

Autumnal Equinox:September 22st

Planetary Motion

Geocentric model:Aristoles Model(Pythagoras and Euclid)Earth was at Centre

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Heliocentric model:Copernicus model,(Galileo and Kepler) sun at centre, Brahe added ellipses, which basically is the way planets orbit.

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Ellipses:Planet orbits the sun in an elliptical, oval, motion around the sun.

Sun Dial

tells the passage of time(tells time)

Merkhet

Charts astronomical positions, and predicts star movements

Quadrant

Measures starts above horizon

Astrolabe

Accurate chart of stars movements

Cross staff

measures angle between moon and stars

Telescope

Allows us to see details in our neighbouring planets, and discover new ones. Also to see whats beyond our earth

Astronomical Unit(AU)

Measures local distance in our solar system, uses the distance between centre of sun to centre of earth or 149,599,000km

Lightyear

Measures distances between galaxies, uses the distance light travels in one year, or 9.5 trillion km

Parsec

Measures distance between stars and galaxies, about 3.26 lightyears.

Light from different astronomical bodies

Sun-8 minutes

light from pluto-5.5 hours

light from stars in the centre of universe-25,000 years

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Rule

The more further away, the longer it takes to reach earth.

stars

hot, glowing ball of gas, made up of mostly hydrogen, and some helium, hot stars of bluish/purplish, and colder stars are redish,yellowish.

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They spend of their lives converting hydrogen into helium.

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Very stable because of the outward pressure of radiation is counteracted by gravity

hertzspring russell model

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Star lifecycle

Starts off made up of gas and dust called interstellar matter and the stage is called nebulae.

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Protostar happens when gravity acts on nebulae collapse and rotate, starbuilding is called fusion.

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Stars get grouped into 2 different groups by their mass, massive stars, and sun like stars.

Main squence

Also known as sun like stars, main sequence go like this

Nebulae→Sun like stars→red giant→white dwarf→black dwarf

Massive stars

Massive stars go like this

Nebulae→Massive stars→Red supergiant→Supernova→Black hole or neutron star

Constellations

Grouping of stars we see as patterns in night sky

ex:ursa major

88 constellations

Asterisms

Grouping of stars, but not an official recognized as a constellation

ex:big dipper is apart of ursa major

Galaxies

Grouping of dust, stars, and gas held together by gravity, 3 types

\-Spiral(our galaxy milky way, is a spiral galaxy)

\-elliptical

\-irregular

Blackholes

They are invisible to telescopes, but is only known through indirect method. We know they exist because when celestial bodies that get near black holes get very bright and very hot.

protoplanet hypothesis

How solar systems become solar systems

1\.cloud dust and gas starts swirling

2\.90% or more of the dust and gas turns into sun

3\.the rest circles the sun

Sun

Centre of solar system, surface is 5000 degrees, and centre is 15,000,000 degrees. A million earths could fit into sun

Solar wind

charged particles traveling pass 400km/s, earth is protected because of magnetic field

Asteroids

Orbits in narrow belt between jupiter and mars, scientists dont know where they come from

comets

known as dirty snowballs, made up of dust and ice, and when ice melts it creates trail

meteoroids, meteors, meteorites

Meteoroids, traveling in space, outside of earth’s atmosphere, meteors aka known as shooting stars entered earth's atmosphere but hasn’t hit ground, meteorites hit ground.

Solar eclispes

Moon passes between sun and earth casting shadow

lunar eclipse

earth travels between sun and moon casting shadow over moon.

Azimuth

compass direction, north is 0 degrees, east is 90 degrees, south is 180 degrees, and west is 270 degrees

altitude

how how in the sky 0-90 degrees

zenith

highest point overhead

motion of objects in space

planet comes from greek word for wanderer

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ecliptic, path in the sky sun appears to move

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celestial sphere, name given to imaginary sphere surrounding earth, aka the atmosphere

what are the 3 biggest challenges to get to space?

1. Speed: to travel fast enough to break free of Earth’s gravity & travel to other planets

2. Extreme environments: to keep equipment operating in space

3. Transport of people: safe travel back and forth

gravitational escape velocity

For an object to go to space, they must overcome the force of gravity which is 28,000km/h

Physics law\*\*\*

for every action, there is an equal opposite reaction

Structural and mechanical part of rocket aka machinery

rocket, engine, storage tank, and fins, makes up 3 percent

fuel

liquid oxygen, gasoline, and liquid hydrogen is ignited in a combustion chamber which causes gas to expand leave as exhaust, makes up 91% of rocket

payload

materials that are needed for the flight, people, food, water, air, etc. Makes up the last 3%

What are ion drives?

Engines that are electrically charged and uses xenox gas. Accelerated and leaves as exhaust, which pushes rocket direction opposite of emission. Thrust lasts a long time, and only needs 1/10 of fuel

What are solar sails?

Like boats, they have sails that catches the suns lights, more specifically the photons(electromagnetic energy). The photons hit the sails and causes the spacecraft to move, these are 5 times more effective than rockets.

what are space probes?

robots used for exploration of space

what are shuttles used for?

transport people, and equipment to orbiting spacecrafts

Spacestations

an orbiting spacecraft that people live in, work, and life supports systems needed to live in space for a long time

international space station(ISS)

Serves as a permanent laboratory in space, and a command post for building and launching interplanetary rockets

Joint project of the US, Canada, Japan, Russia, Brazil and 11 other nations

What are the environment hazards of living in space?

Space is a vacuum with no water and/or air, cosmic rays, solar radiation, and getting hit by meteoroids can have damaging effects, no atmosphere so temperatures can be really hot or really cold, also means no pressure that regulates heartbeats.

Psychological Challenges to Confined Living

Enclosed, small spaces shared by more than one person

Microgravity

Condition where forces acted on mass is greatly reduced, bones have less pressure causing them to expand, heart doesn’t need to pump as hard to regulate blood, muscles get weaken, and visual depth is effected.

Space suit

Space suits are used when astronauts(people in space) leaves spacecraft. everything they need, needs to be brought with them, such as air, water, heating/cooling system, and portable toliet. Suits must be flexible enough to hold a wrench and to twist a bolt incase something of the spacecraft breaks, and has to be custom fit.

Home in space aka spacecrafts

station must provide own power for energy for its own life systems.

Clean water, breathable air, and comfortable air
temperatures and pressures must be provided

Recycling water

ISS recycles 100% of its water

Environmental Control and Life Support System
functions:

Environmental Control and Life Support System
functions:

Recycling wastewater (urine) to produce drinking
water

Using recycled water to produce oxygen

Removing carbon dioxide from the air

Filtering micro-organisms & dust from air

Keeping air pressure, temperature & humidity stable

Producing oxygen

electrolysis uses energy to split water into hydrogen and oxygen, when it happens hydrogen is sent off into space, and oxygen is breathe in.

Satellites and artificial satellites

Satellites are objects that orbits earth, a natural satellite would be the moon. Artificial satellites are satellites we send out to orbit earth.

Role of artificial satellites

Communication: wireless technology

Observation & Research: monitor & forecast weather,
follow ships at sea, monitor soil quality, track forest fires,
report environmental change & search for natural resources

Remote Sensing: observe Earth’s surface, environment,
natural resources, urbanization

Personal Tracking Devices: GPS (global positioning
system) – uses 3/24 satellites to track you

Space age inspired systems plus material

Who is credited with inventing the first telescope to study the sky?

Galileo but in 1608 Hans lippershey made one of the first telescopes

Light collectors

objects that gather and focus from stars;larger the area of lenses or mirrors, the greater the ability to see objects

Refracting Telescope

Uses two lenses to gather and focus starlight.

1\.Objective lense

2\.Eyepiece lens

This limits how large it can be →Diameter has to greater that 1m causes the glass to warp under own weight

Reflecting telescope

Uses mirrors to gather and focus light

1\.Large concave mirror

2\.Secondary flat mirror

\-Mirrors made from glass-like material that has been coated with thin layer of metal(aluminum)

\-Uses a spin casting technique to form large mirrors

Segmented mirror telescope

\-uses several lightweight segments to build one big mirror

\-increases light gaterhing capability and resolving power(ability to distinguish details in an object)

Inferferometry

Technique that combines 2 or more observations from telescopes to produce images that have better resolution than what one telescope could produce alone.

Problems of telescope use on land

Light and air pollution, the weather clouds humidity and high winds

Electromagnet Energy

objects in space emit radio waves, infrared(heat) waves, and X-rays. Energy travels at the speed of light(300,000 km/s) but has different wavelengths and frequences from those light.

Wavelength

Measurement of distance from one point on the wave to the same point on the next wave

Frequency

number of waves that pass a single point in one second

electromagnetic spectrum

complete wavelengths over which electromagnetic energy extends

How are radio telescopes useful and how do they work?

Radio waves give astronomers data not available from visible spectrum. Signals are mapped through a sophisticated electronics and computers

What are radio telescopes made up of, its shape, and how does it work?

THey are made up of metal mesh, they have a shape of a satellite dish, curved inwards with reciever in the middle, the curved part intercepts and focuses the radio waves before transmitting it to a reciever. Waves are transformed into electrical signals that is fed into a computer to be interpreted.

Radio interferometry

Combining 2 small radio telescopes to achieve greater resolving power. Two or more radio telescopes is called an array

space probes

Umanned satellites or remote controlled lands that put equipment close to planets

they gather information about planets that optical and radio telescopes can’t

what is triangulation and what is it used for?

It uses the geometry of a triangle, measures the angles between the baseline of the object, and estimates distance to object.

parallax

shift of an object seen in two different places, used to determine objects distance from earth through triangulation.

Refracting light

white light shone through a prism seperated into different colours

Spectroscopy

black line patterns from stars known as spectra compared to spectra to elements to see what makes up the star