Topic 2:planetary Systems Flashcards
What is the order of the planets
Mercury, Venus, Earth, mars, Jupiter, Saturn, Uranus, Neptune
What dwarf planets is our sun host to
Ceres, Pluto, Eris
What are asteroids
Small solid bodies, with the majority orbiting in the asteroid or main belt between the orbits of mars and Jupiter
What are comets
Nuclei of ice, dust and rock that develop a gaseous coma and tails when relatively close to the sun
What are centaurs
Similar to asteroids and comets. Generally orbit the sun between the orbits of Jupiter and Neptune
What are Trans-Neptunian Objects (TNOs)
Objects orbiting the sun beyond Neptune
What does a body have to be, to be a planet
- in orbit around the sun
- large enough to be spherical
- has ‘cleared its orbit’ of other objects
What is 1 AU equivalent to
150 million km
List some characteristics of mercury
- heavily cratered
- contains highlands and lava-filled basins
- diameter = 4.9,000 km
- temperature = 170 degrees Celsius
List some characteristics of Venus
- has clouds of sulphuric acid
- dense atmosphere containing co2
- diameter = 12.1,000km
- temperature = 470 degrees Celsius
List some characteristics of mars
- has iron-rich rocks
- has a 450km long water-carved canyon
- diameter = 6.8,000km
- temperature = -50 degrees Celsius
List some characteristics of Jupiter
- rotates on its axis in 10 hours
- has a giant red spot which is an anticyclone weather system
- diameter = 143,000km
- temperature = -150 degrees Celsius
List some characteristics of Saturn
- has majestic rings
- is a gas giant
- Diameter = 121,000km
- temperature = -180 degrees Celsius
List some characteristics of Uranus
- ‘surface’ is almost featureless
- compositions of hydrogen, helium, methane and ammonia
- diameter = 51,000km
- temperature = -210 degrees Celsius
List some characteristics of Neptune
- composition of hydrogen, helium , methane and ammonia
- has clouds of frozen methane at high altitudes
- diameter = 50,000 km
- temperature = -220 degrees Celsius
List 3 problems astronauts may face if they venture further into the solar system
- radiation risk
- space adaption syndrome- suffer headaches and vomiting
- physiological problems- brittle bones, muscle fatigue and reduced red blood cell count
What are mars’ moons called and what are they like
Diemos - smaller and more distant of the 2
Phobos
Both irregular in shape , heavily cratered
Neptunes main moons
Triton - slightl smaller that our moon, highly inclined orbit
Dark proteus - second largest moon, largest irregular satellite in solar system
Nereid - largest moon in solar system , takes 360 days to orbit Neptune
What are rings around a planet made from
Individual particles of ice, rock and dust that range from a few microns to several metres in size
What is the shape of an orbit
Ellipse
What narrow region do planets appear to move through
Zodiacal band
What are inferior planets
Planets that orbit inside of the earth - mercury and Venus
What are superior planets
Planets that orbit outside of the earth - mars to Neptune
What are jupiters major moons called
IO , Europa, Callisto, Ganymede
What is the greatest elongation
The angle between the sun and the planet, with the reference point as the earth, when an inferior planets position in its orbit Is at a tangent to the observer on earth
What is conjunction
an alignment of two planets or other celestial objects so that they appear to be in the same, or nearly the same, place in the sky.
What is opposition
When two celestial body’s are in opposite sides of the sky
What is transit
When at least one celestial body moves across the face of another celestial body
What is occulation
When one object is hidden by another object that passes between it and the observer
What is direct motion
Forward motion of planets across the sky
What is retrograde motion
When the inside planet undertakes the outside planet
What are the comets 2 tails
- ion tail - straight and point away from the sun
* dust tail- sticks out behind the comet / opposite to the direction it’s going in. Slightly curved
What are short period comets
Comets that have orbital periods less than 200 years and originate from the Kuiper belt
What are long period comets
Comets that have an orbital period of 200-millions of years and they originate from the Oort Cloud
What do observations of long-period comets indicate
- high percentage originate from vast distances from the sun
* orbits are often highly inclined to the ecliptic
What are meteoroids
Small rocky irregular limbs of debris in the solar system
What are the sources of meteor showers
Debris left behind fro dust tails
What is a meteor
A bright tail of light caused by a meteoroid during its atmospheric flight
What are fireballs
Meteors with a magnitude of -3 or brighter
What is meteorite
Part of meteoroid that survived the passage though the atmosphere
What causes a meteor shower
The increased number of dust particles entering and burning up in the atmosphere
What are examples of collision between astronomical bodies
- craters on planets and moons
* planets rotating on there axis in unusual ways e.g. Backwards, upside down
What effects could a PHO have on the earth
- giant tsunamis
- global dimming - due to dust covering the sun
- disrupting tectonic plates - volcanic eruptions
What can we do to stop pho’s
- send and unnamed space craft to nudge it
* shoot nuclear weapons at it to change its path
What is Kepler 1st law
That planets move in elliptical orbit around the sun, with the sun at one focus of each ellipse
What is keplers 2nd law
An imaginary line from a planet to the su sweeps out equal area in equal intervals of time 8
I.e. At closer points in the orbit the planet moves faster therefore the wedge is bigger even though the number of days is equal
What is keplers 3rd law
T2=r3
T= time period of an orbit
R= average separation
What did Galileo Galileo discover
- the moon was not spherical but contained ‘hollows and protuberances’
- Venus exhibited phases
- 4 satellites were in orbit around Jupiter : io, Callisto, Europe, Ganymede
What is the inverse square law
Distance ^2
What is astrometry
Measuring the precise position of the stars relative to each other, to see if they wobble over time due to the gravitational pull of the exoplanet
What is the transit method
Measuring a dip in the light of a star to see if a planet has moved in front of it
What is Doppler shift
Measuring the lights wavelength or frequency from the star, to see if it changed and if it does it is proof it is moving, so here is probably an exoplanet affecting the stars movement due to its gravity
What are 2 essential chemical ingredients for life
- Carbon- ability to make interesting compounds
* Liquid water
How do astronomers search for signs of life
Space probes
Spectral analysis of planetary atmospheres - search for gases produced by living organisms
What are 3 factors in the Drake equation
Number of stars in our galaxy
Number of planets capable of sustaining life
Fraction of life forms that are intelligent
Why do meteor showers occur about the same time ever year?
Meteor showers occur only when the Earth’s orbit intersects that of a specific comet, and those intersections occur at fixed intervals.
What point in a meteor shower do the meteors appear to diverge from
The radiant
How were Uranus and Neptune discovered
By telescope
How was Pluto discovered
By photography
Which planets have ring systems
Jupiter, Saturn, Uranus, and Neptune
What are the 2 principal origins water on earth is thought to have
- outgassing kg hydrogen and oxygen from volcanoes that combined to produce steam which condensed into water
- it was deposited by comets (containing ice) striking earth
Which 2 of Galileo’s discoveries gave strong evidence in favour of the heliocentric universe
- the phases of Venus
- moons of Jupiter
Who developed the first serious heliocentric model of the universe
Nicolaus Copernicus
What was nicolaus copernicus’ book called
De Revolutionibus Orbium Coelestium (on the revolutions of the celestial spheres) published in 1543
What did Copernicus suggest
That the Earth and planets orbited the sun instead of all heavenly motion being centred on the earth
Who developed the geocentric (earth-centred) universe
The Egyptian philosopher Ptolemy using planetary observations made by Greek astronomer Hipparchus
When was Uranus discovered and who by
1781 by William Herschel
When was Pluto discovered and who by
1930 by Clyde Tombaugh
When was ceres discovered and who by
1801 by Giuseppe Piazza
How was Neptune found
It was predicted by John Couch Adams and Urbain Le Verrier to account for the ‘wobbles’ or perturbations in the motion of Uranus, they suggested these perturbations could only be explained by the existence of another planet that pulled Uranus outwards at time. It was discovered in the first telescopic search
How was Uranus discovered
Herschel was carrying out a ‘review of the heavens’ with a homemade telescope from his garden.he found one star that appeared as a small disc at first he thought it was a comet but subsequent observations allowed him to determine an orbit from which he deduced the object to be a new planet
