lecture 7 Flashcards
lecture 7 material
What was the A3 comet?
when discovered and stuff
- A3 comet discovered in jan 2023
- was going to get very close to the sun; would be bright to be able to see
- was able to be seen in Toronto; very bright
- is fading as it moves away
- nedt one is coming in a decade
- tail grew as heated by sun
- 10-15 degrees
- saw it a couple days ago in Barrie ; very nice
- was going to get very close to the sun; would be bright to be able to see
What was spaceX and starships most recent mission?
- starship test mission
- most powerful rocket since saturn v
about it
- 2 stage
- named starship
- twice the thrust of saturn v
- liquid methane for fuel; resuable
- expected to land NASA on moon in 2026
- expected to allow establishment of mars settlement
- polaris dawn will be upon starship
2 influencial science eduactors and what they did
Carl Sagan
- Tysons inspiration to become a scientist
- wanted to share astronomy info with public
- was ostracized for it
Neil deGrasse Tyson
- the “current Carl Sagan”
- carried on his legacy
- explains complex information very simply
Why do we want to know things about our moon?
- gone to it 6 times with crew
- ~375,000 km away from us
- closest thing to us
- explore it for science
- want to send people there and back more regularly for better investigations (science)
- we all want to understand the solar systems evolution
- understand the changes done
- predict our future
Things we know and things we want to know about our solar system
- mars, earth, and venus, are in the habitable zone of the solar system
- are there any other living beings in our system?
- is our solar system like others?
- our solar system formed about 4.5 billion years ago
-
orbits
- all planets have very similar planes
- all planets orbit the sun in the same direction (counterclockwise)
- Sun takes up 99.8% of our solar systems total mass
- orbiter → land → rover
What are things we know about terrestrial planets?
Mercury, venus, earth, mars
differentiation
- when planets form, were hot and molten (begins this process of differentiation)
- when cooled dense material went to center, forcing less dense material to the crust
- learned of this process by determining density of a planet through earthquakes
characteristics of mercury
- earth like
- rocky world
- very close to sun
- hard to see from earth
- much like our own moon
characteristics of venus
- heats up more than mercury despite being further from sun
- this is bc the atmosphere is so thick (90x of earths) it traps green house gases in the atmosphere
The outer solar system (jovian worlds)
Jupiter, Saturn, Uranus, and Neptune
very different from terrestrial planets
- Jupiter and Saturn are gas giants
- Uranus and Neptune are ice giants
- have different atmospheres (mostly hydrogen and helium) making them colder
- a lot larger then terrestrial planets
- have ring systems
- have more moons bc of large gravitational force bc of large mass
Why does jupiter have stripes/bands?
- action in the jovian atmosphere; heat driving from interior
- the leftover heat from its formation causes swirling
- chemical reactions within the atmopshere gives it its colour (reduction enviornment; hydrogen dominant atmosphere causing swirls)
What is the largest satellite/moon in solar system?
Jupiter has the largest moon called Ganymede
- nearly 5000km in diamter
- has an ocean
Why is jupiter much more resitant to craters?
because of its large size and mass
Shoemaker levy 9 (comet)
- got caught in jupiters gravity, smashed a rock, and created a rubble train of 20 boulders which emmitted a light (visible from earth bc of large speeds and size)
- the energy absorbed from the crash was more energy then earth combined; if it hit us instead we would be dead
Earths craters
- we have very few (find 40-50 per year)
- we keep an eye out for any potentially dangerous ones
Why was pluto demoted to a dwarf planet?
because the definition of a planet has changed since it was found as a planet
- it is smaller then our moon (2.5k in diameter)
- has ice volcanoes (cyclovolcanism)
What is considered a dwarf planet?
asterioids over 100 km in diamter
- it has to have a cratering record
- they are basically bits of material from solar system that never got made into a planet
- are constantly being created in the asteroid belt
What are comets?
- smaller than asteroids
- rich in volatile materials; gaseous ices which escapes when they get near to sun (they emit light)
- come from outer planets which are rich in volatile materials
How do we know how old an object is?
surface age
- the surface age of an object is shown throuh the number of craters in a certain area; more = older
- older = how long since resurfacing has occured; lava flow
- only works if the surface is not geologically active; no lava flow
radioactive dating
- uses instabilty to measure an age accurately
- radioactive element has a half life (loss of parent and creation of daughter)
- basically gives you age of the parent-daughter material when selecting correct half life
- long half life needed to measure rocks
What are some basic things we know about our moon?
- luna far side has more craters; its older
- moon and mercury are very similar in size, appearance and activity (none)
- most of moon in high land material (4.4b years old)
- lunar near side is flatter (3.3b years old)
- moon has no atmopshere bc low gravity
- deficient in volatiles
- moon is not active at all; little internal activity
- APOLLO missions have brought back moon rocks
- luna maria = seas
- dirt on moon is smashed rocks; sharp dont breathe it in
- foot prints will remain on the surface as theres no wind/erosion to move it
