Space Flashcards
What type of radiation do stars emit?
Electromagnetic radiation
What are the 6 layers of the sun? Explain them.
Core:
- nuclear fusion occurs
-15 million degrees celsius
Radiative zone:
- energy released from nuclear fusion enters this zone and continues to move outward
Convective zone:
- hotter substances rise as hotter substances fall
Photosphere:
- light and radiation escape here
-5500 degrees celsius
Chromosphere:
- makes up the inner atmosphere
Corona:
- thin, outer layer of the solar atmosphere
How long does it take the sun to make a complete rotation on it’s axis?
25 days
What causes sunspots?
Disturbances in the sun’s magnetic field
What are sunspots? And what causes them?
Darker, cooler areas visible on sun’s photosphere (first surface).
They are caused by disturbances in the sun’s magnetic field
What are solar flares? What causes them?
Solar flares release large quantities of gas and charged particles above an active sunspot.
They are caused by the rapidly changing magnetic fields around a sunspot.
What are solar prominences? What causes them?
SSolar prominences are slow-low energy ejections of gas that travel through the corona.
They are caused by disturbances in the sun’s magnetic field.
What is the difference between flares and prominences?
Solar flares are eruptions of highly energetic particles on the surface of the sun. They last for a short time only.
Solar prominences are plasma loops that connect two sunspots. They are slow energy ejections of gas.
Solar winds are stronger when there are BLANK and BLANK
Solar flares and solar prominences
How does the Aurora Borealis occur?
When a solar storm comes towards Earth, some of the energy and particles can travel down the magnetic field lines, to the North and South Poles in Earth’s atmosphere. There, these particles interact with the gases in our atmosphere, creating the growing lights.
How can the sun cause communication disruption patterns?
Particles ejected from the sun can damage info stored on computer microchips.
Solar radiation and storms can increase the temperature and density of Earth’s upper atmosphere.
Friction between the satellites and the denser atmosphere slows down the satellite, changing its orbital path.
When is the Earth closest and furthest from the sun?
Closest: Jan 3rd
Furthest: Jul 4th
What is an orbital radius?
The avg distance between an object in the solar system and the sun
Orbital period=revolution.
Revolution vs rotation?
Revolution: An object’s orbital motion around another object
Rotation: An object’s spinning motion around its axis.
At what speed does the Earth spin around its axis?
1,600km/h
At what speed does the Earth revolve around the sun?
108, 000 km/h
Who created the GEOCENTRIC model?
Ptolemy
Who proposed the HELIOCENTRIC model?
Copernicus
What is solstice?
The days of the year on which Earth’s axis is most inclined toward or away from the sun (Summer solstice is the longest day of the year, and winter solstice is the longest night of the year)
What is the equinox?
THINK:Equinox is like Equal
The time of year when the hours of daylight equal the hours of darkness (March 21 is the vernal equinox, and September 21 is the autumnal equinox)
What is precession?
The change in direction of Earth’s rotational axis (similar to a wobble of a spinning top)
We see different amounts of the moon’s lit side in different amounts as it orbits Earth.
We see 8 phases of the moon over 4 weeks in the lunar cycle. What are the phases called
- New moon (the moon is not visible)
- Waxing crescent
- First quarter
- Waxing Gibbous
- Full moon
- Waning Gibbous
- Last quarter
- Waning crescent
New
What is the moon’s position during a solar eclipse?
The moon is aligned between the sun and the Earth, blocking the sun from being observed from Earth.
What happens during a lunar eclipse?
The Earth is between the Sun and the moon, blocking some of the sunlight from reaching the moon.
Why does the moon appear to be red in a lunar eclipse?
As the sun’s light hits Earth’s atmosphere, only the longer wavelengths of light like red are bent into Earth’s umbra.
What is the umbra vs penumbra?
Umbra: the inner part of the shadow from which all light has been blocked
Penumbra: outer part of shadow where the light is only partially blocked.
How do tides occur?
The gravitational forces of the moon pull Earth’s ocean towards it, resulting in a high tide on the side of the Earth facing the moon and the side facing away from the moon.
When the gravitational force of the moon AND the sun are combined (they are aligned) there are very high tides called SPRING TIDES
What are neap tides and what causes them?
Neap tides are very low tides that occur when the sun and moon are perpendicular to one another.
Why do we have artificial satellites orbiting Earth?
Weather forecasting, monitoring agriculture, telecommunications, navigation, exploring the universe and more
What are the 3 types of orbit of a satellite and their altitudes?
Low Earth orbit satellites - Altitude: 2000km
Medium Earth orbit satellites - Altitude: 35,000km
Geostationary orbit satellites: Altitude: 35,790km
What are Low Earth orbit satellites typically used for?
Earth observation (icebergs, agriculture, natural disasters)
What are Medium Earth orbit satellites typically used for?
GPS (Global positioning system)
What are Geostationary orbit satellites typically used for?
Useful for communications and can be linked to antennae on Earth
What are 3 satellites that Canada has launched into Earth’s orbit and their function?
ISS (International Space System): Serves as a home where crews of astronauts live
Radarsat: to observe Earth
Brite: To observe the brightest stars in the sky and to observe the variability in their brightness over time
What is an astronomical unit (AU) vs a light year (ly)?
AU: 150 million kilometres, and used to measure distances within our solar system
ly: 9.46km x 10^12 kilometres, and used to measure distances outside of our solar system
What is luminosity? What is the sun’s luminosity?
The amount of energy produced by a star per second. The sun’s luminosity is 1.
What is the difference between absolute magnitude and apparent magnitude?
Apparent magnitude is the brightness of a star as it appears from Earth.
Absolute magnitude is the brightness of a star as if it was 33ly away from Earth
LOWER magnitude means BLANK
HIGHER brightness
Why do scientists use a spectrograph for?
To analyze the light emitted by stars. It splits light energy into patterns of colours for observation. Each element has its own spectrum.
What is the mass of our sun?
2 x 10^30 kg
Nebula’s collapse in on itself and its gravitational forces form BLANK
A protostar
What happens to a star after the ‘protostar stage’?
The force of gravity cause the atoms in the core to be so tightly packed that the pressure in the core rise and nuclear fusion begins
Why do stars glow?
The nuclear fusion that occurs in the core of the star produces an enormous amount of radiation. The radiation causes the gases around the core to glow.
Death of stars like the sun. Explain it
The star will convert all of its hydrogen into helium, resulting in a helium-rich core, surrounded by a layer of hydrogen.
The outward flow of energy begins to slow and the core begins to contract.
The contract heats the core so much that nuclear fusion can restart in the outer layer
The outer layer of the star expands and then cools, creating a red giant.
Star continues to burn all of its remaining hydrogen, contracts further, and core temperature and pressure rise, causing the core to undergo nuclear fusion!
Helium fuses, producing elements like carbon, and Red Giant is fully formed
As it continues to expand, it sends more gas and dust molecules into space, losing more mass
A star’s core collapses due to the force of its gravity, and outer layers of the star drift away until only the hot core remains. This is called a white dwarf (small, dim, hot)
The white dwarf will continue to radiate energy into space, cooling and dimming until its light goes out. Then it’s a black dwarf.
Red giant to white dwarf only occurs to BLANK.
Star with mass equal to our smaller than the sun.
How big does a star have to be to become a red supergiant?
10 times the mass of the sun
How does iron become in the core of a star during its death?
Once all hydrogen has fused into helium, the helium will be fused into carbon.
Carbon will be fused into oxygen.
This continues until iron is in the core
How does a supernova occur to star that are more massive than the sun?
The star will collapse under its own gravity. The gases rushing to the iron core hits the iron like a wall and bounces back with great force. So, the outer layers of the star explode outwards (supernova)
What happens to a star after a supernova?
10-30 solar masses: neutron star
> 30 solar masses: black hole
How does a neutron star form?
After the supernova, the core collapses, crushing together every proton and electron into a neutron.
How does a black hole form?
Occurs when a star with a mass larger than 30 solar masses dies. All of the material left over from the star falls into a small point
What is a black hole?
A place where gravity is so strong, that nothing can get pulled out - not even light.
How long do stars that are <5 solar masses, 10-30 solar masses, and >30 solar masses undergo nuclear fusion?
<5 solar masses: 10 billion years or 100 billion years if a star is less than 1 solar mass
10-30 solar masses: A few million years
> 30 solar masses: few million years
How do we know a black hole exists when astronomers cannot see them?
The gravitational effect the black has on surrounding objects (it pulls in any matter nearby).
This creates a disc of gas around the hole.
What do we observe on an H-R diagram?
The relationship between a star’s surface temperature and luminosity.
Explain the solar nebula theory
The solar system was formed by a massive nebula that began to contract. The nebula collapses into a disk. A shockwave from a nearby supernova may have triggered the collapse.
The disk spins faster and heats up.
At the center of the disk, a protostar forms.
Lighter gases accumulated in the solar system forming the gas planets, while denser clumps of solid matter remained in the inner solar system, forming terrestrial planets.
Explain the big bang theory
This is the theory that the universe began in a hot, dense expansion approximately 13.7 billion years ago.
All matter and energy in the universe expanded from a hot, dense mass with a small volume
Energy spread outward quickly
As the universe cooled, energy began to turn into matter - mainly hydrogen
Matter formed into clumps over hundreds of millions of years.
These clumps formed into the stars and galaxies.
Which star in the sky doesn’t move?
Polaris, the North Star
What is the name of our galaxy?
The Milky Way
Which galaxy is closest to us?
Andromeda
How many days does it take the sun to make a full rotation?
26 days
Why is the atmosphere essential to life?
The atmosphere contains the oxygen we need to live, protects us from solar radiation, warms our planet and keeps temperatures habitable.
How many days does it take the moon to make a rotation? And an orbit around the Earth?
27.3 days
Why do we always see the same side of the moon?
The rate of rotating and of orbiting is the same
How do we define a planet?
- It is in orbit around the sun
- It has a round shape
- Nothing that is larger crosses it’s orbit
IAU stands for
International Astronomical Union
How many dwarf planets are known?
5
Where is the main asteroid belt?
Between Mars and Jupiter
Which is the largest dwarf planet in our solar system?
Ceres
